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Diffstat (limited to 'js/vendor/image-ssim.js')
| -rw-r--r-- | js/vendor/image-ssim.js | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/js/vendor/image-ssim.js b/js/vendor/image-ssim.js new file mode 100644 index 0000000..e1f07b4 --- /dev/null +++ b/js/vendor/image-ssim.js @@ -0,0 +1,129 @@ +var ImageSSIM; +(function (ImageSSIM) { + 'use strict'; + /** + * Grey = 1, GreyAlpha = 2, RGB = 3, RGBAlpha = 4 + */ + (function (Channels) { + Channels[Channels["Grey"] = 1] = "Grey"; + Channels[Channels["GreyAlpha"] = 2] = "GreyAlpha"; + Channels[Channels["RGB"] = 3] = "RGB"; + Channels[Channels["RGBAlpha"] = 4] = "RGBAlpha"; + })(ImageSSIM.Channels || (ImageSSIM.Channels = {})); + var Channels = ImageSSIM.Channels; + /** + * Entry point. + * @throws new Error('Images have different sizes!') + */ + function compare(image1, image2, windowSize, K1, K2, luminance, bitsPerComponent) { + if (windowSize === void 0) { windowSize = 8; } + if (K1 === void 0) { K1 = 0.01; } + if (K2 === void 0) { K2 = 0.03; } + if (luminance === void 0) { luminance = true; } + if (bitsPerComponent === void 0) { bitsPerComponent = 8; } + if (image1.width !== image2.width || image1.height !== image2.height) { + throw new Error('Images have different sizes!'); + } + /* tslint:disable:no-bitwise */ + var L = (1 << bitsPerComponent) - 1; + /* tslint:enable:no-bitwise */ + var c1 = Math.pow((K1 * L), 2), c2 = Math.pow((K2 * L), 2), numWindows = 0, mssim = 0.0; + var mcs = 0.0; + function iteration(lumaValues1, lumaValues2, averageLumaValue1, averageLumaValue2) { + // calculate variance and covariance + var sigxy, sigsqx, sigsqy; + sigxy = sigsqx = sigsqy = 0.0; + for (var i = 0; i < lumaValues1.length; i++) { + sigsqx += Math.pow((lumaValues1[i] - averageLumaValue1), 2); + sigsqy += Math.pow((lumaValues2[i] - averageLumaValue2), 2); + sigxy += (lumaValues1[i] - averageLumaValue1) * (lumaValues2[i] - averageLumaValue2); + } + var numPixelsInWin = lumaValues1.length - 1; + sigsqx /= numPixelsInWin; + sigsqy /= numPixelsInWin; + sigxy /= numPixelsInWin; + // perform ssim calculation on window + var numerator = (2 * averageLumaValue1 * averageLumaValue2 + c1) * (2 * sigxy + c2); + var denominator = (Math.pow(averageLumaValue1, 2) + Math.pow(averageLumaValue2, 2) + c1) * (sigsqx + sigsqy + c2); + mssim += numerator / denominator; + mcs += (2 * sigxy + c2) / (sigsqx + sigsqy + c2); + numWindows++; + } + // calculate SSIM for each window + Internals._iterate(image1, image2, windowSize, luminance, iteration); + return { ssim: mssim / numWindows, mcs: mcs / numWindows }; + } + ImageSSIM.compare = compare; + /** + * Internal functions. + */ + var Internals; + (function (Internals) { + function _iterate(image1, image2, windowSize, luminance, callback) { + var width = image1.width, height = image1.height; + for (var y = 0; y < height; y += windowSize) { + for (var x = 0; x < width; x += windowSize) { + // avoid out-of-width/height + var windowWidth = Math.min(windowSize, width - x), windowHeight = Math.min(windowSize, height - y); + var lumaValues1 = _lumaValuesForWindow(image1, x, y, windowWidth, windowHeight, luminance), lumaValues2 = _lumaValuesForWindow(image2, x, y, windowWidth, windowHeight, luminance), averageLuma1 = _averageLuma(lumaValues1), averageLuma2 = _averageLuma(lumaValues2); + callback(lumaValues1, lumaValues2, averageLuma1, averageLuma2); + } + } + } + Internals._iterate = _iterate; + function _lumaValuesForWindow(image, x, y, width, height, luminance) { + var array = image.data, lumaValues = new Float32Array(new ArrayBuffer(width * height * 4)), counter = 0; + var maxj = y + height; + for (var j = y; j < maxj; j++) { + var offset = j * image.width; + var i = (offset + x) * image.channels; + var maxi = (offset + x + width) * image.channels; + switch (image.channels) { + case 1 /* Grey */: + while (i < maxi) { + // (0.212655 + 0.715158 + 0.072187) === 1 + lumaValues[counter++] = array[i++]; + } + break; + case 2 /* GreyAlpha */: + while (i < maxi) { + lumaValues[counter++] = array[i++] * (array[i++] / 255); + } + break; + case 3 /* RGB */: + if (luminance) { + while (i < maxi) { + lumaValues[counter++] = (array[i++] * 0.212655 + array[i++] * 0.715158 + array[i++] * 0.072187); + } + } + else { + while (i < maxi) { + lumaValues[counter++] = (array[i++] + array[i++] + array[i++]); + } + } + break; + case 4 /* RGBAlpha */: + if (luminance) { + while (i < maxi) { + lumaValues[counter++] = (array[i++] * 0.212655 + array[i++] * 0.715158 + array[i++] * 0.072187) * (array[i++] / 255); + } + } + else { + while (i < maxi) { + lumaValues[counter++] = (array[i++] + array[i++] + array[i++]) * (array[i++] / 255); + } + } + break; + } + } + return lumaValues; + } + function _averageLuma(lumaValues) { + var sumLuma = 0.0; + for (var i = 0; i < lumaValues.length; i++) { + sumLuma += lumaValues[i]; + } + return sumLuma / lumaValues.length; + } + })(Internals || (Internals = {})); +})(ImageSSIM || (ImageSSIM = {}));
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