private Bitmap preProcessImage(Bitmap image, Grayscale gScale, SobelEdgeDetector sEgDetector, SimplePosterization posterization) { Bitmap temp = image; temp = gScale.Apply(temp); posterization.ApplyInPlace(temp); return temp; }
protected void ApplyFiltersTo(ref Bitmap b, ImageState s) { //TODO: if the image is unrotated, use a rectangle to limit the effect to the desired area string str = null; int i = 0; //If radiusunits is specified, use that code path. double units = s.settings.Get<double>("a.radiusunits",1000); i = GetRadius(s, "blur", "a.blur", units); if (i > 0) new GaussianBlur(1.4, i).ApplyInPlace(b); i = GetRadius(s, "sharpen", "a.sharpen", units); if (i > 0) new GaussianSharpen(1.4, Math.Min(11,i)).ApplyInPlace(b); i = GetRadius(s, "a.oilpainting", null, units); if (i > 0) new OilPainting(i).ApplyInPlace(b); if ("true".Equals(s.settings["a.removenoise"], StringComparison.OrdinalIgnoreCase)) { new ConservativeSmoothing(3).ApplyInPlace(b); } else { i = GetRadius(s, "a.removenoise", null, units); if (i > 0) new ConservativeSmoothing(i).ApplyInPlace(b); } //Sobel only supports 8bpp grayscale images. //true/false if ("true".Equals(s.settings["a.sobel"], StringComparison.OrdinalIgnoreCase)){ Bitmap old = b; try{ b = Grayscale.CommonAlgorithms.Y.Apply(b); }finally{ if (old != s.sourceBitmap) old.Dispose(); } new SobelEdgeDetector().ApplyInPlace(b); str = s.settings["a.threshold"]; //radius if (!string.IsNullOrEmpty(str) && int.TryParse(str, NumberStyles.Integer, NumberFormatInfo.InvariantInfo, out i) && i > 0) new Threshold(i).ApplyInPlace(b); } //Canny Edge Detector only supports 8bpp grayscale images. //true/false if ("true".Equals(s.settings["a.canny"], StringComparison.OrdinalIgnoreCase)) { Bitmap old = b; try { b = Grayscale.CommonAlgorithms.Y.Apply(b); } finally { if (old != s.sourceBitmap) old.Dispose(); } new CannyEdgeDetector().ApplyInPlace(b); } //true/false - duplicate with SimpleFilters? if ("true".Equals(s.settings["a.sepia"], StringComparison.OrdinalIgnoreCase)) new Sepia().ApplyInPlace(b); //true/false if ("true".Equals(s.settings["a.equalize"], StringComparison.OrdinalIgnoreCase)) new HistogramEqualization().ApplyInPlace(b); ///White balance adjustment var whiteAlg = s.settings.Get<HistogramThresholdAlgorithm>("a.balancewhite"); var whiteVal = s.settings.Get<double>("a.balancethreshold"); if (whiteAlg != null || whiteVal != null) { var bal = new AutoWhiteBalance(whiteAlg ?? HistogramThresholdAlgorithm.Area); if (whiteVal != null) bal.LowThreshold = bal.HighThreshold = whiteVal.Value / 100; bal.ApplyInPlace(b); } str = s.settings["a.posterize"]; //number of colors to merge if (!string.IsNullOrEmpty(str) && int.TryParse(str, NumberStyles.Integer, NumberFormatInfo.InvariantInfo, out i) && i > 0) { SimplePosterization sp = new SimplePosterization(); if (i < 1) i = 1; if (i > 255) i = 255; sp.PosterizationInterval =(byte)i; sp.ApplyInPlace(b); } //Pixellate doesn't support 32-bit images, only 24-bit //str = s.settings["a.pixelate"]; //number of colors to merge //if (!string.IsNullOrEmpty(str) && int.TryParse(str, out i)){ // if (i < 2) i = 2; // if (i > 32) i = 32; // new Pixellate(i).ApplyInPlace(s.destBitmap); //} float contrast = s.settings.Get<float>("a.contrast", 0); float brightness = s.settings.Get<float>("a.brightness", 0); float saturation = s.settings.Get<float>("a.saturation", 0); if (contrast != 0 || brightness != 0 || saturation != 0){ HSLLinear adjust = new HSLLinear(); AdjustContrastBrightnessSaturation(adjust, contrast, brightness, saturation, "true".Equals(s.settings["a.truncate"])); adjust.ApplyInPlace(b); } //TODO - add grayscale? //For adding fax-like thresholding, use BradleyLocalThresholding //For trimming solid-color whitespace, use Shrink }
/// <summary> /// Returns true if the average energy of the image is below the given threshold /// </summary> /// <param name="image"></param> /// <param name="threshold"></param> /// <returns></returns> private bool IsBlank(byte[] image, byte threshold) { var ms = new MemoryStream(image); using (var b = new Bitmap(ms)) { using (var gray = Grayscale.CommonAlgorithms.BT709.Apply(b)) { new SobelEdgeDetector().ApplyInPlace(gray); var p = new SimplePosterization(SimplePosterization.PosterizationFillingType.Average); p.PosterizationInterval = 128; p.ApplyInPlace(gray); return gray.GetPixel(0, 0).R < threshold; } } }