OpenCV Computer Vision Samples

// OpenCV.js Basic Operations

// 1. Load OpenCV.js
// In HTML: <script async src="https://docs.opencv.org/4.5.0/opencv.js" onload="onOpenCvReady();"></script>

let cv;

function onOpenCvReady() {
    cv = window.cv;
    console.log('OpenCV.js is ready');
    runBasicExamples();
}

// 2. Load and Display Image
function loadImageAndDisplay(imageElementId, canvasId) {
    const imgElement = document.getElementById(imageElementId);
    const canvasElement = document.getElementById(canvasId);

    const src = cv.imread(imgElement);
    cv.imshow(canvasId, src);

    src.delete();
}

// 3. Basic Image Operations
function basicImageOperations() {
    console.log('=== Basic Image Operations ===');

    const imgElement = document.getElementById('inputImage');
    const src = cv.imread(imgElement);

    // Create destination mat
    const dst = new cv.Mat();

    // Convert to grayscale
    cv.cvtColor(src, dst, cv.COLOR_RGBA2GRAY, 0);
    cv.imshow('grayCanvas', dst);

    // Apply Gaussian blur
    const blurred = new cv.Mat();
    const ksize = new cv.Size(5, 5);
    cv.GaussianBlur(dst, blurred, ksize, 0, 0, cv.BORDER_DEFAULT);
    cv.imshow('blurCanvas', blurred);

    // Edge detection with Canny
    const edges = new cv.Mat();
    cv.Canny(dst, edges, 50, 150, 3, false);
    cv.imshow('edgesCanvas', edges);

    // Clean up
    src.delete();
    dst.delete();
    blurred.delete();
    edges.delete();
}

// 4. Image Filtering and Enhancement
function imageFiltering() {
    console.log('\n=== Image Filtering ===');

    const imgElement = document.getElementById('inputImage');
    const src = cv.imread(imgElement);

    // Histogram Equalization
    const gray = new cv.Mat();
    cv.cvtColor(src, gray, cv.COLOR_RGBA2GRAY, 0);

    const equalized = new cv.Mat();
    cv.equalizeHist(gray, equalized);
    cv.imshow('equalizedCanvas', equalized);

    // Brightness and Contrast Adjustment
    const adjusted = new cv.Mat();
    src.convertTo(adjusted, -1, 1.2, 30); // alpha=1.2 (contrast), beta=30 (brightness)
    cv.imshow('adjustedCanvas', adjusted);

    // Sepia Tone Effect
    const sepia = new cv.Mat();
    const kernel = cv.matFromArray(3, 3, cv.CV_32FC1, [
        0.272, 0.534, 0.131,
        0.349, 0.686, 0.168,
        0.393, 0.769, 0.189
    ]);
    cv.transform(src, sepia, kernel);
    cv.imshow('sepiaCanvas', sepia);

    // Clean up
    src.delete();
    gray.delete();
    equalized.delete();
    adjusted.delete();
    sepia.delete();
    kernel.delete();
}

// 5. Geometric Transformations
function geometricTransformations() {
    console.log('\n=== Geometric Transformations ===');

    const imgElement = document.getElementById('inputImage');
    const src = cv.imread(imgElement);

    // Rotation
    const rotated = new cv.Mat();
    const center = new cv.Point(src.cols / 2, src.rows / 2);
    const rotationMatrix = cv.getRotationMatrix2D(center, 45, 1); // 45 degrees
    cv.warpAffine(src, rotated, rotationMatrix, src.size(), cv.INTER_LINEAR, cv.BORDER_CONSTANT, new cv.Scalar());
    cv.imshow('rotatedCanvas', rotated);

    // Scaling
    const scaled = new cv.Mat();
    const scaleFactor = 0.5;
    const newSize = new cv.Size(src.cols * scaleFactor, src.rows * scaleFactor);
    cv.resize(src, scaled, newSize, 0, 0, cv.INTER_AREA);
    cv.imshow('scaledCanvas', scaled);

    // Translation (shifting)
    const translated = new cv.Mat();
    const translationMatrix = cv.matFromArray(2, 3, cv.CV_64FC1, [
        1, 0, 50,  // shift right by 50
        0, 1, 30   // shift down by 30
    ]);
    cv.warpAffine(src, translated, translationMatrix, src.size());
    cv.imshow('translatedCanvas', translated);

    // Flipping
    const flipped = new cv.Mat();
    cv.flip(src, flipped, 1); // 0 = vertical, 1 = horizontal, -1 = both
    cv.imshow('flippedCanvas', flipped);

    // Clean up
    src.delete();
    rotated.delete();
    scaled.delete();
    translated.delete();
    flipped.delete();
    rotationMatrix.delete();
    translationMatrix.delete();
}

// 6. Morphological Operations
function morphologicalOperations() {
    console.log('\n=== Morphological Operations ===');

    const imgElement = document.getElementById('inputImage');
    const src = cv.imread(imgElement);
    const gray = new cv.Mat();
    cv.cvtColor(src, gray, cv.COLOR_RGBA2GRAY, 0);

    // Binary threshold
    const binary = new cv.Mat();
    cv.threshold(gray, binary, 127, 255, cv.THRESH_BINARY);

    // Erosion
    const eroded = new cv.Mat();
    const kernel = cv.getStructuringElement(cv.MORPH_RECT, new cv.Size(3, 3));
    cv.erode(binary, eroded, kernel);
    cv.imshow('erodedCanvas', eroded);

    // Dilation
    const dilated = new cv.Mat();
    cv.dilate(binary, dilated, kernel);
    cv.imshow('dilatedCanvas', dilated);

    // Opening (Erosion followed by Dilation)
    const opened = new cv.Mat();
    cv.morphologyEx(binary, opened, cv.MORPH_OPEN, kernel);
    cv.imshow('openedCanvas', opened);

    // Closing (Dilation followed by Erosion)
    const closed = new cv.Mat();
    cv.morphologyEx(binary, closed, cv.MORPH_CLOSE, kernel);
    cv.imshow('closedCanvas', closed);

    // Clean up
    src.delete();
    gray.delete();
    binary.delete();
    eroded.delete();
    dilated.delete();
    opened.delete();
    closed.delete();
    kernel.delete();
}

// 7. Face Detection
function faceDetection() {
    console.log('\n=== Face Detection ===');

    const imgElement = document.getElementById('inputImage');
    const src = cv.imread(imgElement);
    const gray = new cv.Mat();

    // Convert to grayscale
    cv.cvtColor(src, gray, cv.COLOR_RGBA2GRAY, 0);

    // Load face cascade classifier
    const faceCascade = new cv.CascadeClassifier();
    faceCascade.load('haarcascade_frontalface_default.xml');

    // Detect faces
    const faces = new cv.RectVector();
    const msize = new cv.Size(0, 0);
    faceCascade.detectMultiScale(gray, faces, 1.1, 3, 0);

    // Draw rectangles around faces
    for (let i = 0; i < faces.size(); ++i) {
        const face = faces.get(i);
        const point1 = new cv.Point(face.x, face.y);
        const point2 = new cv.Point(face.x + face.width, face.y + face.height);
        cv.rectangle(src, point1, point2, [255, 0, 0, 255], 3);
    }

    cv.imshow('faceDetectionCanvas', src);

    console.log(`Detected ${faces.size()} faces`);

    // Clean up
    src.delete();
    gray.delete();
    faces.delete();
    faceCascade.delete();
}

// 8. Object Detection with Template Matching
function templateMatching() {
    console.log('\n=== Template Matching ===');

    const mainImageElement = document.getElementById('mainImage');
    const templateElement = document.getElementById('templateImage');

    const mainImage = cv.imread(mainImageElement);
    const template = cv.imread(templateElement);
    const grayMain = new cv.Mat();
    const grayTemplate = new cv.Mat();

    // Convert to grayscale
    cv.cvtColor(mainImage, grayMain, cv.COLOR_RGBA2GRAY, 0);
    cv.cvtColor(template, grayTemplate, cv.COLOR_RGBA2GRAY, 0);

    // Template matching
    const result = new cv.Mat();
    cv.matchTemplate(grayMain, grayTemplate, result, cv.TM_CCOEFF_NORMED);

    // Find best match
    const minMax = cv.minMaxLoc(result);
    const maxLoc = minMax.maxLoc;
    const color = new cv.Scalar(255, 0, 0, 255);

    // Draw rectangle around match
    const point1 = maxLoc;
    const point2 = new cv.Point(maxLoc.x + template.cols, maxLoc.y + template.rows);
    cv.rectangle(mainImage, point1, point2, color, 2, cv.LINE_8, 0);

    cv.imshow('templateMatchCanvas', mainImage);

    console.log(`Template match found at (${maxLoc.x}, ${maxLoc.y}) with confidence ${minMax.maxVal.toFixed(4)}`);

    // Clean up
    mainImage.delete();
    template.delete();
    grayMain.delete();
    grayTemplate.delete();
    result.delete();
}

// 9. Color Detection and Segmentation
function colorDetection() {
    console.log('\n=== Color Detection ===');

    const imgElement = document.getElementById('inputImage');
    const src = cv.imread(imgElement);
    const hsv = new cv.Mat();

    // Convert to HSV color space
    cv.cvtColor(src, hsv, cv.COLOR_RGBA2RGB);
    cv.cvtColor(hsv, hsv, cv.COLOR_RGB2HSV);

    // Define range for blue color (adjust as needed)
    const lower = new cv.Mat(hsv.rows, hsv.cols, hsv.type(), [100, 50, 50, 0]);
    const upper = new cv.Mat(hsv.rows, hsv.cols, hsv.type(), [130, 255, 255, 255]);

    // Create mask
    const mask = new cv.Mat();
    cv.inRange(hsv, lower, upper, mask);

    // Apply mask to original image
    const result = new cv.Mat();
    src.copyTo(result, mask);

    cv.imshow('colorDetectionCanvas', result);
    cv.imshow('colorMaskCanvas', mask);

    // Find contours
    const contours = new cv.MatVector();
    const hierarchy = new cv.Mat();
    cv.findContours(mask, contours, hierarchy, cv.RETR_EXTERNAL, cv.CHAIN_APPROX_SIMPLE);

    // Draw contours
    const contourImage = src.clone();
    for (let i = 0; i < contours.size(); ++i) {
        const color = new cv.Scalar(Math.random() * 255, Math.random() * 255, Math.random() * 255, 255);
        cv.drawContours(contourImage, contours, i, color, 2, cv.LINE_8, hierarchy, 100);
    }

    cv.imshow('contoursCanvas', contourImage);

    console.log(`Found ${contours.size()} blue objects`);

    // Clean up
    src.delete();
    hsv.delete();
    lower.delete();
    upper.delete();
    mask.delete();
    result.delete();
    contours.delete();
    hierarchy.delete();
    contourImage.delete();
}

// 10. Image Histogram Analysis
function histogramAnalysis() {
    console.log('\n=== Histogram Analysis ===');

    const imgElement = document.getElementById('inputImage');
    const src = cv.imread(imgElement);

    // Calculate histogram for each channel
    const histSize = [256];
    const ranges = [0, 255];
    const channels = [0, 1, 2];

    const hist = new cv.MatVector();
    const mask = new cv.Mat(); // Empty mask
    cv.calcHist(src, channels, mask, hist, histSize, ranges);

    // Create histogram visualization
    const histW = 512;
    const histH = 400;
    const histImage = new cv.Mat.zeros(histH, histW, cv.CV_8UC3);

    // Normalize histogram
    cv.normalize(hist, hist, 0, histImage.rows, cv.NORM_MINMAX);

    // Draw histogram lines
    const binW = Math.round(histW / histSize[0]);
    for (let i = 1; i < histSize[0]; i++) {
        const h = Math.round(hist.get(0, i, 0));
        const h1 = Math.round(hist.get(0, i - 1, 0));
        cv.line(histImage, new cv.Point((i - 1) * binW, histH - h1),
                        new cv.Point(i * binW, histH - h),
                        new cv.Scalar(255, 0, 0, 255), 2, cv.LINE_8, 0);
    }

    cv.imshow('histogramCanvas', histImage);

    // Calculate image statistics
    const mean = cv.mean(src);
    const stddev = new cv.Mat();
    const mean2 = new cv.Mat();
    cv.meanStdDev(src, mean2, stddev);

    console.log('Image Statistics:');
    console.log(`Mean (R,G,B,A): (${mean[0].toFixed(2)}, ${mean[1].toFixed(2)}, ${mean[2].toFixed(2)}, ${mean[3].toFixed(2)})`);
    console.log(`Std Dev: (${stddev.floatAt(0, 0).toFixed(2)}, ${stddev.floatAt(0, 1).toFixed(2)}, ${stddev.floatAt(0, 2).toFixed(2)})`);

    // Clean up
    src.delete();
    hist.delete();
    mask.delete();
    histImage.delete();
    stddev.delete();
    mean2.delete();
}

// 11. Utility Functions
class OpenCVUtils {
    static loadImageFromFile(file, callback) {
        const reader = new FileReader();
        reader.onload = function(e) {
            const imgElement = document.createElement('img');
            imgElement.onload = function() {
                callback(imgElement);
            };
            imgElement.src = e.target.result;
        };
        reader.readAsDataURL(file);
    }

    static downloadCanvas(canvasId, filename) {
        const canvas = document.getElementById(canvasId);
        const link = document.createElement('a');
        link.download = filename;
        link.href = canvas.toDataURL();
        link.click();
    }

    static getCanvasImageData(canvasId) {
        const canvas = document.getElementById(canvasId);
        const ctx = canvas.getContext('2d');
        return ctx.getImageData(0, 0, canvas.width, canvas.height);
    }

    static performanceTimer(start) {
        const end = performance.now();
        return (end - start).toFixed(2) + 'ms';
    }

    static logMemoryUsage() {
        if (performance.memory) {
            console.log('Memory Usage:', {
                used: (performance.memory.usedJSHeapSize / 1048576).toFixed(2) + ' MB',
                total: (performance.memory.totalJSHeapSize / 1048576).toFixed(2) + ' MB',
                limit: (performance.memory.jsHeapSizeLimit / 1048576).toFixed(2) + ' MB'
            });
        }
    }
}

// Main function to run all examples
function runBasicExamples() {
    console.log('Starting OpenCV.js Basic Examples...');

    // Wait for images to load
    setTimeout(() => {
        const startTime = performance.now();

        try {
            basicImageOperations();
            imageFiltering();
            geometricTransformations();
            morphologicalOperations();
            colorDetection();
            histogramAnalysis();

            console.log('\nAll basic examples completed successfully!');
            console.log('Total execution time:', OpenCVUtils.performanceTimer(startTime));
            OpenCVUtils.logMemoryUsage();

        } catch (error) {
            console.error('Error running examples:', error);
        }
    }, 1000);
}

// Export functions for external use
if (typeof module !== 'undefined' && module.exports) {
    module.exports = {
        loadImageAndDisplay,
        basicImageOperations,
        imageFiltering,
        geometricTransformations,
        morphologicalOperations,
        faceDetection,
        templateMatching,
        colorDetection,
        histogramAnalysis,
        OpenCVUtils
    };
}

console.log('OpenCV.js Basic Samples module loaded');
console.log('Make sure to include OpenCV.js in your HTML: <script async src="https://docs.opencv.org/4.5.0/opencv.js"></script>');

// Video Processing with OpenCV.js

let cv;
let video;
let canvas;
let canvasContext;
let streaming = false;
let processingEnabled = true;

// 1. Initialize Video Capture
class VideoProcessor {
    constructor(videoId, canvasId) {
        this.video = document.getElementById(videoId);
        this.canvas = document.getElementById(canvasId);
        this.ctx = this.canvas.getContext('2d');
        this.cap = new cv.VideoCapture(this.video);
        this.processingEnabled = true;
        this.currentFilter = 'normal';
    }

    // Start video stream
    async startVideo() {
        try {
            const stream = await navigator.mediaDevices.getUserMedia({
                video: { width: 640, height: 480 },
                audio: false
            });

            this.video.srcObject = stream;
            this.video.play();

            this.video.addEventListener('loadeddata', () => {
                this.canvas.width = this.video.videoWidth;
                this.canvas.height = this.video.videoHeight;
                streaming = true;
                this.processVideo();
            });

            console.log('Video stream started successfully');
        } catch (error) {
            console.error('Error accessing camera:', error);
        }
    }

    // Stop video stream
    stopVideo() {
        if (this.video.srcObject) {
            this.video.srcObject.getTracks().forEach(track => track.stop());
            this.video.srcObject = null;
            streaming = false;
        }
    }

    // Main processing loop
    processVideo() {
        if (!streaming || !this.processingEnabled) {
            requestAnimationFrame(() => this.processVideo());
            return;
        }

        // Capture frame from video
        const src = new cv.Mat(this.video.height, this.video.width, cv.CV_8UC4);
        this.cap.read(src);

        // Apply selected filter
        let dst = src.clone();
        switch (this.currentFilter) {
            case 'grayscale':
                dst = this.applyGrayscale(src);
                break;
            case 'edge':
                dst = this.applyEdgeDetection(src);
                break;
            case 'blur':
                dst = this.applyBlur(src);
                break;
            case 'cartoon':
                dst = this.applyCartoonEffect(src);
                break;
            case 'motion':
                dst = this.detectMotion(src);
                break;
            default:
                dst = src;
        }

        // Display result
        cv.imshow(this.canvas, dst);

        // Clean up
        if (dst !== src) dst.delete();
        src.delete();

        // Continue processing
        requestAnimationFrame(() => this.processVideo());
    }

    // Apply grayscale filter
    applyGrayscale(src) {
        const gray = new cv.Mat();
        cv.cvtColor(src, gray, cv.COLOR_RGBA2GRAY);
        const dst = new cv.Mat();
        cv.cvtColor(gray, dst, cv.COLOR_GRAY2RGBA);
        gray.delete();
        return dst;
    }

    // Apply edge detection
    applyEdgeDetection(src) {
        const gray = new cv.Mat();
        cv.cvtColor(src, gray, cv.COLOR_RGBA2GRAY);
        const edges = new cv.Mat();
        cv.Canny(gray, edges, 50, 150);
        const dst = new cv.Mat();
        cv.cvtColor(edges, dst, cv.COLOR_GRAY2RGBA);
        gray.delete();
        edges.delete();
        return dst;
    }

    // Apply blur filter
    applyBlur(src) {
        const dst = new cv.Mat();
        const ksize = new cv.Size(15, 15);
        cv.GaussianBlur(src, dst, ksize, 0, 0, cv.BORDER_DEFAULT);
        return dst;
    }

    // Apply cartoon effect
    applyCartoonEffect(src) {
        const gray = new cv.Mat();
        cv.cvtColor(src, gray, cv.COLOR_RGBA2GRAY);

        // Apply bilateral filter multiple times
        let filtered = new cv.Mat();
        cv.bilateralFilter(src, filtered, 15, 80, 80, cv.BORDER_DEFAULT);

        for (let i = 0; i < 2; i++) {
            const temp = filtered.clone();
            cv.bilateralFilter(temp, filtered, 15, 80, 80, cv.BORDER_DEFAULT);
            temp.delete();
        }

        // Create edges
        const edges = new cv.Mat();
        const gray2 = new cv.Mat();
        cv.cvtColor(filtered, gray2, cv.COLOR_RGBA2GRAY);
        cv.medianBlur(gray2, edges, 5);
        const adaptive = new cv.Mat();
        cv.adaptiveThreshold(gray2, adaptive, 255, cv.ADAPTIVE_THRESH_MEAN_C, cv.THRESH_BINARY, 9, 2);

        // Combine edges and filtered image
        const dst = new cv.Mat();
        cv.bitwise_and(filtered, filtered, dst, adaptive);

        // Clean up
        gray.delete();
        filtered.delete();
        edges.delete();
        gray2.delete();
        adaptive.delete();

        return dst;
    }

    // Motion detection
    detectMotion(src) {
        if (!this.previousFrame) {
            this.previousFrame = new cv.Mat();
            cv.cvtColor(src, this.previousFrame, cv.COLOR_RGBA2GRAY);
            return src;
        }

        const gray = new cv.Mat();
        cv.cvtColor(src, gray, cv.COLOR_RGBA2GRAY);

        // Calculate difference
        const diff = new cv.Mat();
        cv.absdiff(gray, this.previousFrame, diff);

        // Threshold
        const thresh = new cv.Mat();
        cv.threshold(diff, thresh, 25, 255, cv.THRESH_BINARY);

        // Find contours
        const contours = new cv.MatVector();
        const hierarchy = new cv.Mat();
        cv.findContours(thresh, contours, hierarchy, cv.RETR_EXTERNAL, cv.CHAIN_APPROX_SIMPLE);

        // Draw rectangles around moving objects
        const dst = src.clone();
        for (let i = 0; i < contours.size(); ++i) {
            const contour = contours.get(i);
            const area = cv.contourArea(contour);

            if (area > 500) { // Filter small movements
                const rect = cv.boundingRect(contour);
                const point1 = new cv.Point(rect.x, rect.y);
                const point2 = new cv.Point(rect.x + rect.width, rect.y + rect.height);
                cv.rectangle(dst, point1, point2, [0, 255, 0, 255], 2);
            }
        }

        // Update previous frame
        this.previousFrame.delete();
        this.previousFrame = gray.clone();

        // Clean up
        gray.delete();
        diff.delete();
        thresh.delete();
        contours.delete();
        hierarchy.delete();

        return dst;
    }

    // Set filter
    setFilter(filterName) {
        this.currentFilter = filterName;
        console.log('Filter changed to:', filterName);
    }

    // Toggle processing
    toggleProcessing() {
        this.processingEnabled = !this.processingEnabled;
        console.log('Processing enabled:', this.processingEnabled);
    }

    // Take snapshot
    takeSnapshot() {
        const dataURL = this.canvas.toDataURL('image/png');
        const link = document.createElement('a');
        link.download = `snapshot_${Date.now()}.png`;
        link.href = dataURL;
        link.click();
        console.log('Snapshot saved');
    }
}

// 2. Face Detection in Video
class FaceDetectionVideo {
    constructor(videoId, canvasId) {
        this.video = document.getElementById(videoId);
        this.canvas = document.getElementById(canvasId);
        this.cap = new cv.VideoCapture(this.video);
        this.faceCascade = null;
        this.eyeCascade = null;
        this.detectionEnabled = true;
    }

    async initialize() {
        try {
            // Load cascade classifiers
            this.faceCascade = new cv.CascadeClassifier();
            this.faceCascade.load('haarcascade_frontalface_default.xml');

            this.eyeCascade = new cv.CascadeClassifier();
            this.eyeCascade.load('haarcascade_eye.xml');

            console.log('Face detection models loaded');
            return true;
        } catch (error) {
            console.error('Error loading face detection models:', error);
            return false;
        }
    }

    startDetection() {
        const processFrame = () => {
            if (!this.detectionEnabled) {
                requestAnimationFrame(processFrame);
                return;
            }

            const src = new cv.Mat(this.video.height, this.video.width, cv.CV_8UC4);
            const gray = new cv.Mat();
            this.cap.read(src);

            // Convert to grayscale
            cv.cvtColor(src, gray, cv.COLOR_RGBA2GRAY, 0);

            // Detect faces
            const faces = new cv.RectVector();
            this.faceCascade.detectMultiScale(gray, faces, 1.1, 3, 0);

            // Draw rectangles around faces and detect eyes
            for (let i = 0; i < faces.size(); ++i) {
                const face = faces.get(i);
                const point1 = new cv.Point(face.x, face.y);
                const point2 = new cv.Point(face.x + face.width, face.y + face.height);
                cv.rectangle(src, point1, point2, [255, 0, 0, 255], 3);

                // Detect eyes within face region
                const faceROI = gray.roi(face);
                const eyes = new cv.RectVector();
                this.eyeCascade.detectMultiScale(faceROI, eyes, 1.1, 10, 0);

                // Draw eye rectangles
                for (let j = 0; j < eyes.size(); ++j) {
                    const eye = eyes.get(j);
                    const eyePoint1 = new cv.Point(
                        face.x + eye.x,
                        face.y + eye.y
                    );
                    const eyePoint2 = new cv.Point(
                        face.x + eye.x + eye.width,
                        face.y + eye.y + eye.height
                    );
                    cv.rectangle(src, eyePoint1, eyePoint2, [0, 255, 255, 255], 2);
                }

                faceROI.delete();
                eyes.delete();
            }

            cv.imshow(this.canvas, src);

            // Display face count
            document.getElementById('faceCount').textContent = faces.size();

            src.delete();
            gray.delete();
            faces.delete();

            requestAnimationFrame(processFrame);
        };

        processFrame();
    }

    toggleDetection() {
        this.detectionEnabled = !this.detectionEnabled;
        console.log('Face detection enabled:', this.detectionEnabled);
    }
}

// 3. Object Tracking
class ObjectTracker {
    constructor(videoId, canvasId) {
        this.video = document.getElementById(videoId);
        this.canvas = document.getElementById(canvasId);
        this.cap = new cv.VideoCapture(this.video);
        this.tracker = null;
        this.tracking = false;
        this.roi = null;
    }

    initializeTracker(trackerType = 'KCF') {
        const trackerTypes = ['BOOSTING', 'MIL', 'KCF', 'TLD', 'MEDIANFLOW', 'GOTURN', 'MOSSE', 'CSRT'];
        const trackerTypeIndex = trackerTypes.indexOf(trackerType);

        if (trackerTypeIndex === -1) {
            console.error('Invalid tracker type');
            return false;
        }

        try {
            this.tracker = new cv.TrackerCSRT_create(); // CSRT is more reliable
            console.log(`${trackerType} tracker initialized`);
            return true;
        } catch (error) {
            console.error('Error initializing tracker:', error);
            return false;
        }
    }

    selectROI(event) {
        if (!this.tracker) {
            alert('Please initialize tracker first');
            return;
        }

        const rect = cv.selectROI('ObjectTracking', this.video, false, false);
        if (rect.width > 0 && rect.height > 0) {
            this.roi = rect;
            this.startTracking();
        }
    }

    startTracking() {
        if (!this.tracker || !this.roi) return;

        // Initialize tracker with ROI
        this.tracker.init(this.roi, this.cap.read());
        this.tracking = true;
        this.track();
    }

    track() {
        if (!this.tracking) return;

        const processFrame = () => {
            if (!this.tracking) return;

            const frame = this.cap.read();
            if (frame.empty) {
                console.log('Video ended');
                return;
            }

            // Update tracker
            const ok = this.tracker.update(frame);

            if (ok) {
                // Draw tracked object
                const trackedRect = this.tracker.getRegion();
                cv.rectangle(frame,
                    new cv.Point(trackedRect.x, trackedRect.y),
                    new cv.Point(trackedRect.x + trackedRect.width, trackedRect.y + trackedRect.height),
                    [0, 255, 0, 255], 3);
            } else {
                cv.putText(frame, 'Tracking failure detected', new cv.Point(100, 80),
                    cv.FONT_HERSHEY_SIMPLEX, 0.75, [0, 0, 255, 255], 2);
            }

            cv.imshow(this.canvas, frame);
            frame.delete();

            requestAnimationFrame(processFrame);
        };

        processFrame();
    }

    stopTracking() {
        this.tracking = false;
        console.log('Tracking stopped');
    }
}

// 4. Motion Detection and Alert System
class MotionDetector {
    constructor(videoId, canvasId) {
        this.video = document.getElementById(videoId);
        this.canvas = document.getElementById(canvasId);
        this.cap = new cv.VideoCapture(this.video);
        this.previousFrame = null;
        this.motionThreshold = 25;
        this.minContourArea = 500;
        this.alertCallback = null;
        this.detectionEnabled = true;
        this.motionHistory = [];
        this.maxHistoryLength = 10;
    }

    setAlertCallback(callback) {
        this.alertCallback = callback;
    }

    startDetection() {
        const processFrame = () => {
            if (!this.detectionEnabled) {
                requestAnimationFrame(processFrame);
                return;
            }

            const frame = this.cap.read();
            if (frame.empty) {
                requestAnimationFrame(processFrame);
                return;
            }

            const gray = new cv.Mat();
            cv.cvtColor(frame, gray, cv.COLOR_RGBA2GRAY, 0);
            cv.GaussianBlur(gray, gray, new cv.Size(21, 21), 0);

            let motionDetected = false;
            const output = frame.clone();

            if (this.previousFrame) {
                // Calculate difference
                const diff = new cv.Mat();
                cv.absdiff(gray, this.previousFrame, diff);

                // Threshold
                const thresh = new cv.Mat();
                cv.threshold(diff, thresh, this.motionThreshold, 255, cv.THRESH_BINARY);

                // Dilate to fill holes
                const dilated = new cv.Mat();
                cv.dilate(thresh, dilated, cv.getStructuringElement(cv.MORPH_RECT, new cv.Size(7, 7)));

                // Find contours
                const contours = new cv.MatVector();
                const hierarchy = new cv.Mat();
                cv.findContours(dilated, contours, hierarchy, cv.RETR_EXTERNAL, cv.CHAIN_APPROX_SIMPLE);

                let totalMotionArea = 0;
                for (let i = 0; i < contours.size(); ++i) {
                    const contour = contours.get(i);
                    const area = cv.contourArea(contour);

                    if (area > this.minContourArea) {
                        motionDetected = true;
                        totalMotionArea += area;

                        // Draw bounding rectangle
                        const rect = cv.boundingRect(contour);
                        cv.rectangle(output,
                            new cv.Point(rect.x, rect.y),
                            new cv.Point(rect.x + rect.width, rect.y + rect.height),
                            [0, 255, 0, 255], 2);
                    }
                }

                // Update motion history
                this.motionHistory.push({
                    detected: motionDetected,
                    area: totalMotionArea,
                    timestamp: Date.now()
                });

                if (this.motionHistory.length > this.maxHistoryLength) {
                    this.motionHistory.shift();
                }

                // Trigger alert if significant motion
                if (motionDetected && totalMotionArea > 5000) {
                    if (this.alertCallback) {
                        this.alertCallback({
                            detected: true,
                            area: totalMotionArea,
                            timestamp: Date.now()
                        });
                    }

                    // Draw alert text
                    cv.putText(output, 'MOTION DETECTED', new cv.Point(10, 30),
                        cv.FONT_HERSHEY_SIMPLEX, 1, [0, 0, 255, 255], 2);
                }

                // Display motion indicator
                const motionLevel = Math.min(255, totalMotionArea / 100);
                cv.rectangle(output, new cv.Point(10, output.rows - 40),
                    new cv.Point(10 + motionLevel, output.rows - 20),
                    [0, motionLevel, 255 - motionLevel, 255], -1);

                // Clean up
                diff.delete();
                thresh.delete();
                dilated.delete();
                contours.delete();
                hierarchy.delete();
            }

            // Update previous frame
            if (this.previousFrame) {
                this.previousFrame.delete();
            }
            this.previousFrame = gray.clone();

            cv.imshow(this.canvas, output);

            frame.delete();
            output.delete();

            requestAnimationFrame(processFrame);
        };

        processFrame();
    }

    getMotionStatistics() {
        if (this.motionHistory.length === 0) {
            return { averageMotion: 0, motionFrequency: 0 };
        }

        const recentMotion = this.motionHistory.slice(-5);
        const motionCount = recentMotion.filter(m => m.detected).length;
        const averageArea = recentMotion.reduce((sum, m) => sum + m.area, 0) / recentMotion.length;

        return {
            motionFrequency: (motionCount / recentMotion.length) * 100,
            averageMotionArea: averageArea
        };
    }
}

// 5. Video Recorder
class VideoRecorder {
    constructor(canvasId) {
        this.canvas = document.getElementById(canvasId);
        this.mediaRecorder = null;
        this.recordedChunks = [];
        this.recording = false;
    }

    startRecording() {
        if (this.recording) return;

        const stream = this.canvas.captureStream(30); // 30 FPS
        this.mediaRecorder = new MediaRecorder(stream, {
            mimeType: 'video/webm'
        });

        this.recordedChunks = [];

        this.mediaRecorder.ondataavailable = (event) => {
            if (event.data.size > 0) {
                this.recordedChunks.push(event.data);
            }
        };

        this.mediaRecorder.onstop = () => {
            const blob = new Blob(this.recordedChunks, {
                type: 'video/webm'
            });
            const url = URL.createObjectURL(blob);
            const link = document.createElement('a');
            link.href = url;
            link.download = `recording_${Date.now()}.webm`;
            link.click();
            URL.revokeObjectURL(url);
        };

        this.mediaRecorder.start();
        this.recording = true;
        console.log('Recording started');
    }

    stopRecording() {
        if (!this.recording || !this.mediaRecorder) return;

        this.mediaRecorder.stop();
        this.recording = false;
        console.log('Recording stopped');
    }

    isRecording() {
        return this.recording;
    }
}

// 6. Initialize all components
function initializeVideoProcessing() {
    console.log('Initializing Video Processing...');

    // Wait for OpenCV to load
    if (typeof cv === 'undefined') {
        setTimeout(initializeVideoProcessing, 100);
        return;
    }

    // Initialize video processor
    const videoProcessor = new VideoProcessor('videoInput', 'canvasOutput');
    videoProcessor.startVideo();

    // Set up filter buttons
    document.querySelectorAll('.filter-btn').forEach(btn => {
        btn.addEventListener('click', () => {
            videoProcessor.setFilter(btn.dataset.filter);
        });
    });

    // Set up snapshot button
    document.getElementById('snapshotBtn').addEventListener('click', () => {
        videoProcessor.takeSnapshot();
    });

    // Initialize face detection
    const faceDetector = new FaceDetectionVideo('videoInput', 'faceCanvas');
    faceDetector.initialize().then(success => {
        if (success) {
            faceDetector.startDetection();
        }
    });

    // Initialize motion detector
    const motionDetector = new MotionDetector('videoInput', 'motionCanvas');
    motionDetector.setAlertCallback((alert) => {
        console.log('Motion Alert:', alert);
        document.getElementById('motionAlert').textContent =
            `Motion detected! Area: ${alert.area.toFixed(0)} pixels`;
    });
    motionDetector.startDetection();

    // Initialize video recorder
    const videoRecorder = new VideoRecorder('canvasOutput');

    document.getElementById('recordBtn').addEventListener('click', () => {
        if (videoRecorder.isRecording()) {
            videoRecorder.stopRecording();
            document.getElementById('recordBtn').textContent = 'Start Recording';
        } else {
            videoRecorder.startRecording();
            document.getElementById('recordBtn').textContent = 'Stop Recording';
        }
    });

    console.log('Video processing initialized successfully');
}

// Export classes for external use
if (typeof module !== 'undefined' && module.exports) {
    module.exports = {
        VideoProcessor,
        FaceDetectionVideo,
        ObjectTracker,
        MotionDetector,
        VideoRecorder
    };
}

// Auto-initialize when page loads
document.addEventListener('DOMContentLoaded', () => {
    initializeVideoProcessing();
});

console.log('OpenCV.js Video Processing module loaded');

// Advanced OpenCV.js Applications

let cv;

// 1. Augmented Reality Face Filters
class ARFaceFilters {
    constructor(videoId, canvasId) {
        this.video = document.getElementById(videoId);
        this.canvas = document.getElementById(canvasId);
        this.cap = new cv.VideoCapture(this.video);
        this.faceCascade = null;
        this.currentFilter = 'none';
        this.overlayImage = null;
        this.filterEnabled = true;
    }

    async initialize() {
        try {
            this.faceCascade = new cv.CascadeClassifier();
            this.faceCascade.load('haarcascade_frontalface_default.xml');

            // Load filter overlays
            await this.loadFilterImages();

            console.log('AR Face Filters initialized');
            return true;
        } catch (error) {
            console.error('Error initializing AR filters:', error);
            return false;
        }
    }

    async loadFilterImages() {
        const filters = {
            sunglasses: 'path/to/sunglasses.png',
            mustache: 'path/to/mustache.png',
            hat: 'path/to/hat.png',
            mask: 'path/to/mask.png'
        };

        // Preload filter images (would need actual image files)
        for (const [name, path] of Object.entries(filters)) {
            // This would load actual images in practice
            console.log(`Loading filter: ${name}`);
        }
    }

    applyARFilter() {
        if (!this.filterEnabled) return;

        const src = new cv.Mat(this.video.height, this.video.width, cv.CV_8UC4);
        const gray = new cv.Mat();
        this.cap.read(src);

        cv.cvtColor(src, gray, cv.COLOR_RGBA2GRAY, 0);

        // Detect faces
        const faces = new cv.RectVector();
        this.faceCascade.detectMultiScale(gray, faces, 1.1, 3, 0);

        // Apply filter to each detected face
        for (let i = 0; i < faces.size(); ++i) {
            const face = faces.get(i);

            switch (this.currentFilter) {
                case 'sunglasses':
                    this.applySunglasses(src, face);
                    break;
                case 'mustache':
                    this.applyMustache(src, face);
                    break;
                case 'hat':
                    this.applyHat(src, face);
                    break;
                case 'mask':
                    this.applyMask(src, face);
                    break;
                case 'beautify':
                    this.beautifyFace(src, face);
                    break;
            }
        }

        cv.imshow(this.canvas, src);

        // Clean up
        src.delete();
        gray.delete();
        faces.delete();
    }

    applySunglasses(image, face) {
        const glassesWidth = face.width * 0.8;
        const glassesHeight = face.height * 0.3;
        const glassesX = face.x + face.width * 0.1;
        const glassesY = face.y + face.height * 0.3;

        // Draw sunglasses (simplified as rectangle)
        const roi = image.roi(new cv.Rect(glassesX, glassesY, glassesWidth, glassesHeight));
        const darkGlasses = roi.clone();
        darkGlasses.setTo([0, 0, 0, 180]); // Dark black with transparency
        darkGlasses.copyTo(roi);

        roi.delete();
        darkGlasses.delete();
    }

    applyMustache(image, face) {
        const mustacheWidth = face.width * 0.4;
        const mustacheHeight = face.height * 0.1;
        const mustacheX = face.x + face.width * 0.3;
        const mustacheY = face.y + face.height * 0.6;

        // Draw mustache
        cv.rectangle(image,
            new cv.Point(mustacheX, mustacheY),
            new cv.Point(mustacheX + mustacheWidth, mustacheY + mustacheHeight),
            [0, 0, 0, 255], -1);
    }

    applyHat(image, face) {
        const hatWidth = face.width * 1.2;
        const hatHeight = face.height * 0.4;
        const hatX = face.x - face.width * 0.1;
        const hatY = face.y - face.height * 0.3;

        // Draw hat
        cv.rectangle(image,
            new cv.Point(hatX, hatY),
            new cv.Point(hatX + hatWidth, hatY + hatHeight),
            [128, 0, 128, 255], -1);
    }

    applyMask(image, face) {
        const maskWidth = face.width * 0.9;
        const maskHeight = face.height * 0.3;
        const maskX = face.x + face.width * 0.05;
        const maskY = face.y + face.height * 0.4;

        // Draw medical mask
        cv.rectangle(image,
            new cv.Point(maskX, maskY),
            new cv.Point(maskX + maskWidth, maskY + maskHeight),
            [200, 200, 200, 255], -1);
    }

    beautifyFace(image, face) {
        const roi = image.roi(face);
        const beautified = roi.clone();

        // Apply subtle smoothing
        cv.bilateralFilter(beautified, beautified, 15, 30, 30, cv.BORDER_DEFAULT);

        // Slight brightness adjustment
        beautified.convertTo(beautified, -1, 1.1, 10);

        beautified.copyTo(roi);

        roi.delete();
        beautified.delete();
    }

    start() {
        const process = () => {
            if (this.filterEnabled) {
                this.applyARFilter();
            }
            requestAnimationFrame(process);
        };
        process();
    }

    setFilter(filterName) {
        this.currentFilter = filterName;
        console.log('AR Filter changed to:', filterName);
    }

    toggleFilter() {
        this.filterEnabled = !this.filterEnabled;
    }
}

// 2. Barcode and QR Code Scanner
class BarcodeScanner {
    constructor(videoId, canvasId) {
        this.video = document.getElementById(videoId);
        this.canvas = document.getElementById(canvasId);
        this.cap = new cv.VideoCapture(this.video);
        this.scanning = true;
        this.detectedCodes = [];
        this.onCodeDetected = null;
    }

    startScanning() {
        const processFrame = () => {
            if (!this.scanning) {
                requestAnimationFrame(processFrame);
                return;
            }

            const src = new cv.Mat(this.video.height, this.video.width, cv.CV_8UC4);
            const gray = new cv.Mat();
            this.cap.read(src);

            cv.cvtColor(src, gray, cv.COLOR_RGBA2GRAY, 0);

            // Detect barcodes (simplified - would need proper barcode library)
            const barcodes = this.detectBarcodes(gray);

            // Draw bounding boxes
            for (const barcode of barcodes) {
                cv.rectangle(src,
                    new cv.Point(barcode.x, barcode.y),
                    new cv.Point(barcode.x + barcode.width, barcode.y + barcode.height),
                    [0, 255, 0, 255], 3);

                cv.putText(src, barcode.data,
                    new cv.Point(barcode.x, barcode.y - 10),
                    cv.FONT_HERSHEY_SIMPLEX, 0.5, [0, 255, 0, 255], 2);

                // Trigger callback if new code detected
                if (!this.detectedCodes.includes(barcode.data)) {
                    this.detectedCodes.push(barcode.data);
                    if (this.onCodeDetected) {
                        this.onCodeDetected(barcode);
                    }
                }
            }

            cv.imshow(this.canvas, src);

            // Clean up
            src.delete();
            gray.delete();

            requestAnimationFrame(processFrame);
        };

        processFrame();
    }

    detectBarcodes(grayImage) {
        // Simplified barcode detection
        // In practice, you would use a dedicated barcode/QR code library

        const barcodes = [];

        // Apply adaptive threshold
        const binary = new cv.Mat();
        cv.adaptiveThreshold(grayImage, binary, 255, cv.ADAPTIVE_THRESH_GAUSSIAN_C, cv.THRESH_BINARY, 11, 2);

        // Find contours
        const contours = new cv.MatVector();
        const hierarchy = new cv.Mat();
        cv.findContours(binary, contours, hierarchy, cv.RETR_TREE, cv.CHAIN_APPROX_SIMPLE);

        // Filter contours that look like barcodes
        for (let i = 0; i < contours.size(); ++i) {
            const contour = contours.get(i);
            const rect = cv.boundingRect(contour);
            const aspectRatio = rect.width / rect.height;

            // Typical barcode aspect ratios and dimensions
            if (aspectRatio > 2.0 && rect.width > 50 && rect.height > 10) {
                barcodes.push({
                    x: rect.x,
                    y: rect.y,
                    width: rect.width,
                    height: rect.height,
                    data: `BARCODE_${Date.now()}_${i}` // Simulated barcode data
                });
            }
        }

        binary.delete();
        contours.delete();
        hierarchy.delete();

        return barcodes;
    }

    onCodeDetected(callback) {
        this.onCodeDetected = callback;
    }

    clearDetectedCodes() {
        this.detectedCodes = [];
    }

    toggleScanning() {
        this.scanning = !this.scanning;
    }
}

// 3. Image Stitching and Panorama
class ImageStitcher {
    constructor(canvasId) {
        this.canvas = document.getElementById(canvasId);
        this.images = [];
        this.keypoints = [];
        this.descriptors = [];
        this.matcher = null;
    }

    addImage(imageElement) {
        const mat = cv.imread(imageElement);
        this.images.push(mat);

        // Detect keypoints
        const gray = new cv.Mat();
        cv.cvtColor(mat, gray, cv.COLOR_RGBA2GRAY, 0);

        const orb = new cv.ORB(1000);
        const keypoints = new cv.KeyPointVector();
        const descriptors = new cv.Mat();

        orb.detectAndCompute(gray, new cv.Mat(), keypoints, descriptors);

        this.keypoints.push(keypoints);
        this.descriptors.push(descriptors);

        gray.delete();

        console.log(`Added image ${this.images.length} with ${keypoints.size()} keypoints`);
    }

    stitchImages() {
        if (this.images.length < 2) {
            console.error('Need at least 2 images for stitching');
            return null;
        }

        // Match features between consecutive images
        const matches = this.matchFeatures(
            this.descriptors[0],
            this.descriptors[1]
        );

        // Find homography
        const homography = this.findHomography(
            this.keypoints[0],
            this.keypoints[1],
            matches
        );

        // Warp images
        const panorama = this.warpImages(this.images[0], this.images[1], homography);

        // Display result
        cv.imshow(this.canvas, panorama);

        // Clean up
        matches.delete();
        homography.delete();

        return panorama;
    }

    matchFeatures(desc1, desc2) {
        // Use brute-force matcher
        const matcher = new cv.BFMatcher(cv.NORM_HAMMING, false);
        const matches = new cv.DMatchVector();
        matcher.match(desc1, desc2, matches);

        // Filter matches by distance
        const goodMatches = [];
        for (let i = 0; i < matches.size(); ++i) {
            const match = matches.get(i);
            if (match.distance < 30) { // Threshold
                goodMatches.push(match);
            }
        }

        const goodMatchesVector = new cv.DMatchVector();
        goodMatches.forEach(match => goodMatchesVector.push_back(match));

        matches.delete();
        return goodMatchesVector;
    }

    findHomography(kp1, kp2, matches) {
        const srcPoints = [];
        const dstPoints = [];

        for (let i = 0; i < matches.size(); ++i) {
            const match = matches.get(i);
            srcPoints.push(kp1.get(match.queryIdx).pt);
            dstPoints.push(kp2.get(match.trainIdx).pt);
        }

        // Convert to cv.Mat
        const srcMat = cv.matFromArray(srcPoints.length, 1, cv.CV_32FC2,
            srcPoints.flat());
        const dstMat = cv.matFromArray(dstPoints.length, 1, cv.CV_32FC2,
            dstPoints.flat());

        const homography = cv.findHomography(srcMat, dstMat, cv.RANSAC, 5.0);

        srcMat.delete();
        dstMat.delete();

        return homography;
    }

    warpImages(img1, img2, homography) {
        // Get corners of first image
        const corners1 = [
            [0, 0],
            [img1.cols, 0],
            [img1.cols, img1.rows],
            [0, img1.rows]
        ];

        // Transform corners
        const corners2 = [];
        for (const corner of corners1) {
            const mat = cv.matFromArray(1, 1, cv.CV_32FC2, corner);
            const transformed = cv.perspectiveTransform(mat, homography);
            corners2.push(transformed.data32F);
            mat.delete();
            transformed.delete();
        }

        // Calculate output size
        const allCorners = [...corners1, ...corners2];
        const minX = Math.min(...allCorners.map(c => c[0]));
        const minY = Math.min(...allCorners.map(c => c[1]));
        const maxX = Math.max(...allCorners.map(c => c[0]));
        const maxY = Math.max(...allCorners.map(c => c[1]));

        const outputWidth = Math.ceil(maxX - minX);
        const outputHeight = Math.ceil(maxY - minY);

        // Create translation matrix
        const translation = cv.matFromArray(3, 3, cv.CV_64FC1, [
            1, 0, -minX,
            0, 1, -minY,
            0, 0, 1
        ]);

        // Adjust homography
        const adjustedHomography = new cv.Mat();
        cv.gemm(translation, homography, 1, new cv.Mat(), 0, adjustedHomography);

        // Warp images
        const panorama = new cv.Mat();
        cv.warpPerspective(img1, panorama, adjustedHomography,
            new cv.Size(outputWidth, outputHeight));

        // Place second image
        const roi = panorama.roi(new cv.Rect(-minX, -minY, img2.cols, img2.rows));
        img2.copyTo(roi);

        // Clean up
        translation.delete();
        adjustedHomography.delete();
        roi.delete();

        return panorama;
    }

    clearImages() {
        this.images.forEach(img => img.delete());
        this.keypoints.forEach(kp => kp.delete());
        this.descriptors.forEach(desc => desc.delete());

        this.images = [];
        this.keypoints = [];
        this.descriptors = [];
    }
}

// 4. 3D Object Detection (Simplified)
class Object3DDetector {
    constructor(videoId, canvasId) {
        this.video = document.getElementById(videoId);
        this.canvas = document.getElementById(canvasId);
        this.cap = new cv.VideoCapture(this.video);
        this.objects = [];
        this.detectorEnabled = true;
    }

    add3DObject(name, features) {
        this.objects.push({
            name,
            features: features, // Would be SIFT/SURF features in practice
            color: [Math.random() * 255, Math.random() * 255, Math.random() * 255, 255]
        });
    }

    detect3DObjects() {
        const processFrame = () => {
            if (!this.detectorEnabled) {
                requestAnimationFrame(processFrame);
                return;
            }

            const src = new cv.Mat(this.video.height, this.video.width, cv.CV_8UC4);
            const gray = new cv.Mat();
            this.cap.read(src);

            cv.cvtColor(src, gray, cv.COLOR_RGBA2GRAY, 0);

            // Simplified 3D object detection
            // In practice, would use feature matching with 3D reconstruction

            const detectedObjects = this.performObjectDetection(gray);

            // Draw detected objects
            for (const obj of detectedObjects) {
                // Draw bounding box
                cv.rectangle(src,
                    new cv.Point(obj.x, obj.y),
                    new cv.Point(obj.x + obj.width, obj.y + obj.height),
                    obj.color, 3);

                // Draw label
                cv.putText(src, obj.name,
                    new cv.Point(obj.x, obj.y - 10),
                    cv.FONT_HERSHEY_SIMPLEX, 0.7, obj.color, 2);

                // Draw 3D axes (simplified)
                this.draw3DAxes(src, obj);
            }

            // Draw coordinate system
            this.drawCoordinateSystem(src);

            cv.imshow(this.canvas, src);

            src.delete();
            gray.delete();

            requestAnimationFrame(processFrame);
        };

        processFrame();
    }

    performObjectDetection(grayImage) {
        // Simplified object detection
        // Would use SURF/BRISK features and matching in practice

        const detectedObjects = [];

        // Use template matching as simplified approach
        for (const obj of this.objects) {
            // This would be proper feature matching in practice
            if (Math.random() > 0.7) { // Simulate detection
                detectedObjects.push({
                    name: obj.name,
                    x: Math.random() * (grayImage.cols - 100),
                    y: Math.random() * (grayImage.rows - 100),
                    width: 80 + Math.random() * 40,
                    height: 80 + Math.random() * 40,
                    color: obj.color,
                    pose: {
                        pitch: Math.random() * 360,
                        yaw: Math.random() * 360,
                        roll: Math.random() * 360
                    }
                });
            }
        }

        return detectedObjects;
    }

    draw3DAxes(image, object) {
        const centerX = object.x + object.width / 2;
        const centerY = object.y + object.height / 2;
        const axisLength = 50;

        // X-axis (red)
        const xEnd = new cv.Point(
            centerX + axisLength * Math.cos(object.pose.yaw * Math.PI / 180),
            centerY + axisLength * Math.sin(object.pose.yaw * Math.PI / 180)
        );
        cv.arrowedLine(image, new cv.Point(centerX, centerY), xEnd, [0, 0, 255, 255], 3);

        // Y-axis (green)
        const yEnd = new cv.Point(
            centerX + axisLength * Math.cos((object.pose.yaw + 90) * Math.PI / 180),
            centerY + axisLength * Math.sin((object.pose.yaw + 90) * Math.PI / 180)
        );
        cv.arrowedLine(image, new cv.Point(centerX, centerY), yEnd, [0, 255, 0, 255], 3);
    }

    drawCoordinateSystem(image) {
        // Draw small coordinate system in corner
        const origin = new cv.Point(50, image.rows - 50);
        const axisLength = 30;

        // X-axis
        const xEnd = new cv.Point(origin.x + axisLength, origin.y);
        cv.arrowedLine(image, origin, xEnd, [255, 0, 0, 255], 2);

        // Y-axis
        const yEnd = new cv.Point(origin.x, origin.y - axisLength);
        cv.arrowedLine(image, origin, yEnd, [0, 255, 0, 255], 2);

        // Labels
        cv.putText(image, 'X', new cv.Point(xEnd.x + 5, xEnd.y),
            cv.FONT_HERSHEY_SIMPLEX, 0.5, [255, 0, 0, 255], 1);
        cv.putText(image, 'Y', new cv.Point(yEnd.x, yEnd.y - 5),
            cv.FONT_HERSHEY_SIMPLEX, 0.5, [0, 255, 0, 255], 1);
    }

    startDetection() {
        this.detect3DObjects();
    }

    toggleDetection() {
        this.detectorEnabled = !this.detectorEnabled;
    }
}

// 5. Gesture Recognition
class GestureRecognizer {
    constructor(videoId, canvasId) {
        this.video = document.getElementById(videoId);
        this.canvas = document.getElementById(canvasId);
        this.cap = new cv.VideoCapture(this.video);
        this.handCascade = null;
        this.currentGesture = 'none';
        this.gestureCallback = null;
        this.recognitionEnabled = true;
        this.gestureHistory = [];
        this.maxHistoryLength = 10;
    }

    async initialize() {
        try {
            // Load hand cascade classifier
            this.handCascade = new cv.CascadeClassifier();
            this.handCascade.load('palm.xml'); // Would need actual palm detection model

            console.log('Gesture Recognizer initialized');
            return true;
        } catch (error) {
            console.error('Error initializing gesture recognizer:', error);
            return false;
        }
    }

    recognizeGestures() {
        const processFrame = () => {
            if (!this.recognitionEnabled) {
                requestAnimationFrame(processFrame);
                return;
            }

            const src = new cv.Mat(this.video.height, this.video.width, cv.CV_8UC4);
            const gray = new cv.Mat();
            this.cap.read(src);

            cv.cvtColor(src, gray, cv.COLOR_RGBA2GRAY, 0);

            // Detect hands (simplified)
            const hands = this.detectHands(gray);

            // Recognize gestures
            const gestures = [];
            for (const hand of hands) {
                const gesture = this.classifyGesture(gray, hand);
                gestures.push(gesture);

                // Draw hand and gesture
                cv.rectangle(src,
                    new cv.Point(hand.x, hand.y),
                    new cv.Point(hand.x + hand.width, hand.y + hand.height),
                    [255, 0, 0, 255], 2);

                cv.putText(src, gesture.name,
                    new cv.Point(hand.x, hand.y - 10),
                    cv.FONT_HERSHEY_SIMPLEX, 0.7, [0, 255, 0, 255], 2);
            }

            // Update gesture history
            if (gestures.length > 0) {
                this.gestureHistory.push({
                    gesture: gestures[0].name,
                    confidence: gestures[0].confidence,
                    timestamp: Date.now()
                });

                if (this.gestureHistory.length > this.maxHistoryLength) {
                    this.gestureHistory.shift();
                }

                // Trigger callback if gesture is consistent
                if (this.gestureHistory.length >= 5) {
                    const recentGestures = this.gestureHistory.slice(-3);
                    const consistent = recentGestures.every(g => g.gesture === recentGestures[0].gesture);

                    if (consistent && recentGestures[0].confidence > 0.7) {
                        this.currentGesture = recentGestures[0].gesture;

                        if (this.gestureCallback) {
                            this.gestureCallback({
                                gesture: this.currentGesture,
                                confidence: recentGestures[0].confidence
                            });
                        }
                    }
                }
            }

            // Display current gesture
            cv.putText(src, `Gesture: ${this.currentGesture}`,
                new cv.Point(10, 30),
                cv.FONT_HERSHEY_SIMPLEX, 1, [255, 255, 255, 255], 2);

            cv.imshow(this.canvas, src);

            src.delete();
            gray.delete();

            requestAnimationFrame(processFrame);
        };

        processFrame();
    }

    detectHands(grayImage) {
        // Simplified hand detection
        // In practice, would use skin color detection or specialized hand detector

        const hands = [];

        // Use adaptive threshold to find hand-like regions
        const binary = new cv.Mat();
        cv.adaptiveThreshold(grayImage, binary, 255, cv.ADAPTIVE_THRESH_GAUSSIAN_C, cv.THRESH_BINARY, 11, 2);

        // Find contours
        const contours = new cv.MatVector();
        const hierarchy = new cv.Mat();
        cv.findContours(binary, contours, hierarchy, cv.RETR_TREE, cv.CHAIN_APPROX_SIMPLE);

        // Filter for hand-like contours
        for (let i = 0; i < contours.size(); ++i) {
            const contour = contours.get(i);
            const area = cv.contourArea(contour);
            const hull = new cv.Mat();
            cv.convexHull(contour, hull);

            // Hand characteristics (simplified)
            const hullArea = cv.contourArea(hull);
            const solidity = area / hullArea;

            if (area > 1000 && solidity < 0.9) {
                const rect = cv.boundingRect(contour);
                hands.push({
                    x: rect.x,
                    y: rect.y,
                    width: rect.width,
                    height: rect.height,
                    contour: contour
                });
            }

            hull.delete();
        }

        binary.delete();
        contours.delete();
        hierarchy.delete();

        return hands;
    }

    classifyGesture(grayImage, hand) {
        // Simplified gesture classification
        // In practice, would analyze finger count, hand shape, etc.

        const handROI = grayImage.roi(hand);
        const moments = cv.moments(handROI);

        // Calculate features
        const huMoments = cv.HuMoments(moments);

        // Simple classification based on contour properties
        let gesture = 'unknown';
        let confidence = 0.5;

        // Random gesture assignment for demonstration
        const gestures = ['fist', 'open_palm', 'peace', 'thumbs_up', 'pointing'];
        gesture = gestures[Math.floor(Math.random() * gestures.length)];
        confidence = 0.6 + Math.random() * 0.4;

        handROI.delete();

        return { gesture, confidence };
    }

    onGestureDetected(callback) {
        this.gestureCallback = callback;
    }

    startRecognition() {
        this.recognizeGestures();
    }

    toggleRecognition() {
        this.recognitionEnabled = !this.recognitionEnabled;
    }

    getGestureHistory() {
        return this.gestureHistory;
    }
}

// 6. Initialize all advanced applications
function initializeAdvancedApps() {
    console.log('Initializing Advanced OpenCV Applications...');

    // Wait for OpenCV
    if (typeof cv === 'undefined') {
        setTimeout(initializeAdvancedApps, 100);
        return;
    }

    // Initialize AR Face Filters
    const arFilters = new ARFaceFilters('videoInput', 'arCanvas');
    arFilters.initialize().then(() => {
        arFilters.start();
    });

    // Set up AR filter controls
    document.querySelectorAll('.ar-filter-btn').forEach(btn => {
        btn.addEventListener('click', () => {
            arFilters.setFilter(btn.dataset.filter);
        });
    });

    // Initialize Barcode Scanner
    const barcodeScanner = new BarcodeScanner('videoInput', 'barcodeCanvas');
    barcodeScanner.onCodeDetected((code) => {
        console.log('Barcode detected:', code);
        document.getElementById('barcodeResult').textContent = `Detected: ${code.data}`;
    });
    barcodeScanner.startScanning();

    // Initialize Image Stitcher
    const imageStitcher = new ImageStitcher('panoramaCanvas');

    document.getElementById('addImage1Btn').addEventListener('click', () => {
        const input = document.createElement('input');
        input.type = 'file';
        input.accept = 'image/*';
        input.onchange = (e) => {
            const file = e.target.files[0];
            const reader = new FileReader();
            reader.onload = (event) => {
                const img = document.createElement('img');
                img.onload = () => {
                    imageStitcher.addImage(img);
                };
                img.src = event.target.result;
            };
            reader.readAsDataURL(file);
        };
        input.click();
    });

    document.getElementById('stitchBtn').addEventListener('click', () => {
        imageStitcher.stitchImages();
    });

    // Initialize 3D Object Detector
    const detector3D = new Object3DDetector('videoInput', '3dCanvas');
    detector3D.add3DObject('Cube', { /* features */ });
    detector3D.add3DObject('Sphere', { /* features */ });
    detector3D.startDetection();

    // Initialize Gesture Recognizer
    const gestureRecognizer = new GestureRecognizer('videoInput', 'gestureCanvas');
    gestureRecognizer.initialize().then(() => {
        gestureRecognizer.onGestureDetected((gesture) => {
            console.log('Gesture detected:', gesture);
            document.getElementById('gestureResult').textContent =
                `Gesture: ${gesture.gesture} (Confidence: ${(gesture.confidence * 100).toFixed(1)}%)`;
        });
        gestureRecognizer.startRecognition();
    });

    console.log('Advanced applications initialized');
}

// Export classes for external use
if (typeof module !== 'undefined' && module.exports) {
    module.exports = {
        ARFaceFilters,
        BarcodeScanner,
        ImageStitcher,
        Object3DDetector,
        GestureRecognizer
    };
}

// Auto-initialize
document.addEventListener('DOMContentLoaded', () => {
    initializeAdvancedApps();
});

console.log('Advanced OpenCV.js Applications module loaded');