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Filename : barcode_locator.js
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import ImageWrapper from '../common/image_wrapper';
import {
    calculatePatchSize,
    otsuThreshold,
    hsv2rgb,
    cluster,
    topGeneric,
    imageRef,
    halfSample,
    computeImageArea
} from '../common/cv_utils';
import ArrayHelper from '../common/array_helper';
import ImageDebug from '../common/image_debug';
import Rasterizer from './rasterizer';
import Tracer from './tracer';
import skeletonizer from './skeletonizer';
const vec2 = {
    clone: require('gl-vec2/clone'),
    dot:  require('gl-vec2/dot'),
    scale: require('gl-vec2/scale'),
    transformMat2: require('gl-vec2/transformMat2')
};
const mat2 = {
    copy: require('gl-mat2/copy'),
    create: require('gl-mat2/create'),
    invert: require('gl-mat2/invert')
}

var _config,
    _currentImageWrapper,
    _skelImageWrapper,
    _subImageWrapper,
    _labelImageWrapper,
    _patchGrid,
    _patchLabelGrid,
    _imageToPatchGrid,
    _binaryImageWrapper,
    _patchSize,
    _canvasContainer = {
        ctx: {
            binary: null
        },
        dom: {
            binary: null
        }
    },
    _numPatches = {x: 0, y: 0},
    _inputImageWrapper,
    _skeletonizer;

function initBuffers() {
    var skeletonImageData;

    if (_config.halfSample) {
        _currentImageWrapper = new ImageWrapper({
            x: _inputImageWrapper.size.x / 2 | 0,
            y: _inputImageWrapper.size.y / 2 | 0
        });
    } else {
        _currentImageWrapper = _inputImageWrapper;
    }

    _patchSize = calculatePatchSize(_config.patchSize, _currentImageWrapper.size);

    _numPatches.x = _currentImageWrapper.size.x / _patchSize.x | 0;
    _numPatches.y = _currentImageWrapper.size.y / _patchSize.y | 0;

    _binaryImageWrapper = new ImageWrapper(_currentImageWrapper.size, undefined, Uint8Array, false);

    _labelImageWrapper = new ImageWrapper(_patchSize, undefined, Array, true);

    skeletonImageData = new ArrayBuffer(64 * 1024);
    _subImageWrapper = new ImageWrapper(_patchSize,
        new Uint8Array(skeletonImageData, 0, _patchSize.x * _patchSize.y));
    _skelImageWrapper = new ImageWrapper(_patchSize,
        new Uint8Array(skeletonImageData, _patchSize.x * _patchSize.y * 3, _patchSize.x * _patchSize.y),
        undefined, true);
    _skeletonizer = skeletonizer((typeof window !== 'undefined') ? window : (typeof self !== 'undefined') ? self : global, {
        size: _patchSize.x
    }, skeletonImageData);

    _imageToPatchGrid = new ImageWrapper({
        x: (_currentImageWrapper.size.x / _subImageWrapper.size.x) | 0,
        y: (_currentImageWrapper.size.y / _subImageWrapper.size.y) | 0
    }, undefined, Array, true);
    _patchGrid = new ImageWrapper(_imageToPatchGrid.size, undefined, undefined, true);
    _patchLabelGrid = new ImageWrapper(_imageToPatchGrid.size, undefined, Int32Array, true);
}

function initCanvas() {
    if (_config.useWorker || typeof document === 'undefined') {
        return;
    }
    _canvasContainer.dom.binary = document.createElement("canvas");
    _canvasContainer.dom.binary.className = "binaryBuffer";
    if (ENV.development && _config.debug.showCanvas === true) {
        document.querySelector("#debug").appendChild(_canvasContainer.dom.binary);
    }
    _canvasContainer.ctx.binary = _canvasContainer.dom.binary.getContext("2d");
    _canvasContainer.dom.binary.width = _binaryImageWrapper.size.x;
    _canvasContainer.dom.binary.height = _binaryImageWrapper.size.y;
}

/**
 * Creates a bounding box which encloses all the given patches
 * @returns {Array} The minimal bounding box
 */
function boxFromPatches(patches) {
    var overAvg,
        i,
        j,
        patch,
        transMat,
        minx =
        _binaryImageWrapper.size.x,
        miny = _binaryImageWrapper.size.y,
        maxx = -_binaryImageWrapper.size.x,
        maxy = -_binaryImageWrapper.size.y,
        box,
        scale;

    // draw all patches which are to be taken into consideration
    overAvg = 0;
    for ( i = 0; i < patches.length; i++) {
        patch = patches[i];
        overAvg += patch.rad;
        if (ENV.development && _config.debug.showPatches) {
            ImageDebug.drawRect(patch.pos, _subImageWrapper.size, _canvasContainer.ctx.binary, {color: "red"});
        }
    }

    overAvg /= patches.length;
    overAvg = (overAvg * 180 / Math.PI + 90) % 180 - 90;
    if (overAvg < 0) {
        overAvg += 180;
    }

    overAvg = (180 - overAvg) * Math.PI / 180;
    transMat = mat2.copy(mat2.create(), [Math.cos(overAvg), Math.sin(overAvg), -Math.sin(overAvg), Math.cos(overAvg)]);

    // iterate over patches and rotate by angle
    for ( i = 0; i < patches.length; i++) {
        patch = patches[i];
        for ( j = 0; j < 4; j++) {
            vec2.transformMat2(patch.box[j], patch.box[j], transMat);
        }

        if (ENV.development && _config.debug.boxFromPatches.showTransformed) {
            ImageDebug.drawPath(patch.box, {x: 0, y: 1}, _canvasContainer.ctx.binary, {color: '#99ff00', lineWidth: 2});
        }
    }

    // find bounding box
    for ( i = 0; i < patches.length; i++) {
        patch = patches[i];
        for ( j = 0; j < 4; j++) {
            if (patch.box[j][0] < minx) {
                minx = patch.box[j][0];
            }
            if (patch.box[j][0] > maxx) {
                maxx = patch.box[j][0];
            }
            if (patch.box[j][1] < miny) {
                miny = patch.box[j][1];
            }
            if (patch.box[j][1] > maxy) {
                maxy = patch.box[j][1];
            }
        }
    }

    box = [[minx, miny], [maxx, miny], [maxx, maxy], [minx, maxy]];

    if (ENV.development && _config.debug.boxFromPatches.showTransformedBox) {
        ImageDebug.drawPath(box, {x: 0, y: 1}, _canvasContainer.ctx.binary, {color: '#ff0000', lineWidth: 2});
    }

    scale = _config.halfSample ? 2 : 1;
    // reverse rotation;
    transMat = mat2.invert(transMat, transMat);
    for ( j = 0; j < 4; j++) {
        vec2.transformMat2(box[j], box[j], transMat);
    }

    if (ENV.development && _config.debug.boxFromPatches.showBB) {
        ImageDebug.drawPath(box, {x: 0, y: 1}, _canvasContainer.ctx.binary, {color: '#ff0000', lineWidth: 2});
    }

    for ( j = 0; j < 4; j++) {
        vec2.scale(box[j], box[j], scale);
    }

    return box;
}

/**
 * Creates a binary image of the current image
 */
function binarizeImage() {
    otsuThreshold(_currentImageWrapper, _binaryImageWrapper);
    _binaryImageWrapper.zeroBorder();
    if (ENV.development && _config.debug.showCanvas) {
        _binaryImageWrapper.show(_canvasContainer.dom.binary, 255);
    }
}

/**
 * Iterate over the entire image
 * extract patches
 */
function findPatches() {
    var i,
        j,
        x,
        y,
        moments,
        patchesFound = [],
        rasterizer,
        rasterResult,
        patch;
    for (i = 0; i < _numPatches.x; i++) {
        for (j = 0; j < _numPatches.y; j++) {
            x = _subImageWrapper.size.x * i;
            y = _subImageWrapper.size.y * j;

            // seperate parts
            skeletonize(x, y);

            // Rasterize, find individual bars
            _skelImageWrapper.zeroBorder();
            ArrayHelper.init(_labelImageWrapper.data, 0);
            rasterizer = Rasterizer.create(_skelImageWrapper, _labelImageWrapper);
            rasterResult = rasterizer.rasterize(0);

            if (ENV.development && _config.debug.showLabels) {
                _labelImageWrapper.overlay(_canvasContainer.dom.binary, Math.floor(360 / rasterResult.count),
                    {x: x, y: y});
            }

            // calculate moments from the skeletonized patch
            moments = _labelImageWrapper.moments(rasterResult.count);

            // extract eligible patches
            patchesFound = patchesFound.concat(describePatch(moments, [i, j], x, y));
        }
    }

    if (ENV.development && _config.debug.showFoundPatches) {
        for ( i = 0; i < patchesFound.length; i++) {
            patch = patchesFound[i];
            ImageDebug.drawRect(patch.pos, _subImageWrapper.size, _canvasContainer.ctx.binary,
                {color: "#99ff00", lineWidth: 2});
        }
    }

    return patchesFound;
}

/**
 * Finds those connected areas which contain at least 6 patches
 * and returns them ordered DESC by the number of contained patches
 * @param {Number} maxLabel
 */
function findBiggestConnectedAreas(maxLabel){
    var i,
        sum,
        labelHist = [],
        topLabels = [];

    for ( i = 0; i < maxLabel; i++) {
        labelHist.push(0);
    }
    sum = _patchLabelGrid.data.length;
    while (sum--) {
        if (_patchLabelGrid.data[sum] > 0) {
            labelHist[_patchLabelGrid.data[sum] - 1]++;
        }
    }

    labelHist = labelHist.map(function(val, idx) {
        return {
            val: val,
            label: idx + 1
        };
    });

    labelHist.sort(function(a, b) {
        return b.val - a.val;
    });

    // extract top areas with at least 6 patches present
    topLabels = labelHist.filter(function(el) {
        return el.val >= 5;
    });

    return topLabels;
}

/**
 *
 */
function findBoxes(topLabels, maxLabel) {
    var i,
        j,
        sum,
        patches = [],
        patch,
        box,
        boxes = [],
        hsv = [0, 1, 1],
        rgb = [0, 0, 0];

    for ( i = 0; i < topLabels.length; i++) {
        sum = _patchLabelGrid.data.length;
        patches.length = 0;
        while (sum--) {
            if (_patchLabelGrid.data[sum] === topLabels[i].label) {
                patch = _imageToPatchGrid.data[sum];
                patches.push(patch);
            }
        }
        box = boxFromPatches(patches);
        if (box) {
            boxes.push(box);

            // draw patch-labels if requested
            if (ENV.development && _config.debug.showRemainingPatchLabels) {
                for ( j = 0; j < patches.length; j++) {
                    patch = patches[j];
                    hsv[0] = (topLabels[i].label / (maxLabel + 1)) * 360;
                    hsv2rgb(hsv, rgb);
                    ImageDebug.drawRect(patch.pos, _subImageWrapper.size, _canvasContainer.ctx.binary,
                        {color: "rgb(" + rgb.join(",") + ")", lineWidth: 2});
                }
            }
        }
    }
    return boxes;
}

/**
 * Find similar moments (via cluster)
 * @param {Object} moments
 */
function similarMoments(moments) {
    var clusters = cluster(moments, 0.90);
    var topCluster = topGeneric(clusters, 1, function(e) {
        return e.getPoints().length;
    });
    var points = [], result = [];
    if (topCluster.length === 1) {
        points = topCluster[0].item.getPoints();
        for (var i = 0; i < points.length; i++) {
            result.push(points[i].point);
        }
    }
    return result;
}

function skeletonize(x, y) {
    _binaryImageWrapper.subImageAsCopy(_subImageWrapper, imageRef(x, y));
    _skeletonizer.skeletonize();

    // Show skeleton if requested
    if (ENV.development && _config.debug.showSkeleton) {
        _skelImageWrapper.overlay(_canvasContainer.dom.binary, 360, imageRef(x, y));
    }
}

/**
 * Extracts and describes those patches which seem to contain a barcode pattern
 * @param {Array} moments
 * @param {Object} patchPos,
 * @param {Number} x
 * @param {Number} y
 * @returns {Array} list of patches
 */
function describePatch(moments, patchPos, x, y) {
    var k,
        avg,
        eligibleMoments = [],
        matchingMoments,
        patch,
        patchesFound = [],
        minComponentWeight = Math.ceil(_patchSize.x / 3);

    if (moments.length >= 2) {
        // only collect moments which's area covers at least minComponentWeight pixels.
        for ( k = 0; k < moments.length; k++) {
            if (moments[k].m00 > minComponentWeight) {
                eligibleMoments.push(moments[k]);
            }
        }

        // if at least 2 moments are found which have at least minComponentWeights covered
        if (eligibleMoments.length >= 2) {
            matchingMoments = similarMoments(eligibleMoments);
            avg = 0;
            // determine the similarity of the moments
            for ( k = 0; k < matchingMoments.length; k++) {
                avg += matchingMoments[k].rad;
            }

            // Only two of the moments are allowed not to fit into the equation
            // add the patch to the set
            if (matchingMoments.length > 1
                    && matchingMoments.length >= (eligibleMoments.length / 4) * 3
                    && matchingMoments.length > moments.length / 4) {
                avg /= matchingMoments.length;
                patch = {
                    index: patchPos[1] * _numPatches.x + patchPos[0],
                    pos: {
                        x: x,
                        y: y
                    },
                    box: [
                        vec2.clone([x, y]),
                        vec2.clone([x + _subImageWrapper.size.x, y]),
                        vec2.clone([x + _subImageWrapper.size.x, y + _subImageWrapper.size.y]),
                        vec2.clone([x, y + _subImageWrapper.size.y])
                    ],
                    moments: matchingMoments,
                    rad: avg,
                    vec: vec2.clone([Math.cos(avg), Math.sin(avg)])
                };
                patchesFound.push(patch);
            }
        }
    }
    return patchesFound;
}

/**
 * finds patches which are connected and share the same orientation
 * @param {Object} patchesFound
 */
function rasterizeAngularSimilarity(patchesFound) {
    var label = 0,
        threshold = 0.95,
        currIdx = 0,
        j,
        patch,
        hsv = [0, 1, 1],
        rgb = [0, 0, 0];

    function notYetProcessed() {
        var i;
        for ( i = 0; i < _patchLabelGrid.data.length; i++) {
            if (_patchLabelGrid.data[i] === 0 && _patchGrid.data[i] === 1) {
                return i;
            }
        }
        return _patchLabelGrid.length;
    }

    function trace(currentIdx) {
        var x,
            y,
            currentPatch,
            idx,
            dir,
            current = {
                x: currentIdx % _patchLabelGrid.size.x,
                y: (currentIdx / _patchLabelGrid.size.x) | 0
            },
            similarity;

        if (currentIdx < _patchLabelGrid.data.length) {
            currentPatch = _imageToPatchGrid.data[currentIdx];
            // assign label
            _patchLabelGrid.data[currentIdx] = label;
            for ( dir = 0; dir < Tracer.searchDirections.length; dir++) {
                y = current.y + Tracer.searchDirections[dir][0];
                x = current.x + Tracer.searchDirections[dir][1];
                idx = y * _patchLabelGrid.size.x + x;

                // continue if patch empty
                if (_patchGrid.data[idx] === 0) {
                    _patchLabelGrid.data[idx] = Number.MAX_VALUE;
                    continue;
                }

                if (_patchLabelGrid.data[idx] === 0) {
                    similarity = Math.abs(vec2.dot(_imageToPatchGrid.data[idx].vec, currentPatch.vec));
                    if (similarity > threshold) {
                        trace(idx);
                    }
                }
            }
        }
    }

    // prepare for finding the right patches
    ArrayHelper.init(_patchGrid.data, 0);
    ArrayHelper.init(_patchLabelGrid.data, 0);
    ArrayHelper.init(_imageToPatchGrid.data, null);

    for ( j = 0; j < patchesFound.length; j++) {
        patch = patchesFound[j];
        _imageToPatchGrid.data[patch.index] = patch;
        _patchGrid.data[patch.index] = 1;
    }

    // rasterize the patches found to determine area
    _patchGrid.zeroBorder();

    while (( currIdx = notYetProcessed()) < _patchLabelGrid.data.length) {
        label++;
        trace(currIdx);
    }

    // draw patch-labels if requested
    if (ENV.development && _config.debug.showPatchLabels) {
        for ( j = 0; j < _patchLabelGrid.data.length; j++) {
            if (_patchLabelGrid.data[j] > 0 && _patchLabelGrid.data[j] <= label) {
                patch = _imageToPatchGrid.data[j];
                hsv[0] = (_patchLabelGrid.data[j] / (label + 1)) * 360;
                hsv2rgb(hsv, rgb);
                ImageDebug.drawRect(patch.pos, _subImageWrapper.size, _canvasContainer.ctx.binary,
                    {color: "rgb(" + rgb.join(",") + ")", lineWidth: 2});
            }
        }
    }

    return label;
}

export default {
    init: function(inputImageWrapper, config) {
        _config = config;
        _inputImageWrapper = inputImageWrapper;

        initBuffers();
        initCanvas();
    },

    locate: function() {
        var patchesFound,
            topLabels,
            boxes;

        if (_config.halfSample) {
            halfSample(_inputImageWrapper, _currentImageWrapper);
        }

        binarizeImage();
        patchesFound = findPatches();
        // return unless 5% or more patches are found
        if (patchesFound.length < _numPatches.x * _numPatches.y * 0.05) {
            return null;
        }

        // rasterrize area by comparing angular similarity;
        var maxLabel = rasterizeAngularSimilarity(patchesFound);
        if (maxLabel < 1) {
            return null;
        }

        // search for area with the most patches (biggest connected area)
        topLabels = findBiggestConnectedAreas(maxLabel);
        if (topLabels.length === 0) {
            return null;
        }

        boxes = findBoxes(topLabels, maxLabel);
        return boxes;
    },

    checkImageConstraints: function(inputStream, config) {
        var patchSize,
            width = inputStream.getWidth(),
            height = inputStream.getHeight(),
            halfSample = config.halfSample ? 0.5 : 1,
            size,
            area;

        // calculate width and height based on area
        if (inputStream.getConfig().area) {
            area = computeImageArea(width, height, inputStream.getConfig().area);
            inputStream.setTopRight({x: area.sx, y: area.sy});
            inputStream.setCanvasSize({x: width, y: height});
            width = area.sw;
            height = area.sh;
        }

        size = {
            x: Math.floor(width * halfSample),
            y: Math.floor(height * halfSample)
        };

        patchSize = calculatePatchSize(config.patchSize, size);
        if (ENV.development) {
            console.log("Patch-Size: " + JSON.stringify(patchSize));
        }

        inputStream.setWidth(Math.floor(Math.floor(size.x / patchSize.x) * (1 / halfSample) * patchSize.x));
        inputStream.setHeight(Math.floor(Math.floor(size.y / patchSize.y) * (1 / halfSample) * patchSize.y));

        if ((inputStream.getWidth() % patchSize.x) === 0 && (inputStream.getHeight() % patchSize.y) === 0) {
            return true;
        }

        throw new Error("Image dimensions do not comply with the current settings: Width (" +
            width + " )and height (" + height +
            ") must a multiple of " + patchSize.x);
    }
};