public static void UpdateThresholds(ICollection <Tag> tags, Rectangle roiRect, uint frameBuffer, uint roiTexName)
{
// Setup resultTexName framebuffer
int[] oldViewPort = new int[4];
GL.GetInteger(GetPName.Viewport, oldViewPort);
GL.Viewport(0, 0, roiRect.Size.Width, roiRect.Size.Height);
int fboOld = GLHelper.bindFrameBuffer(frameBuffer, roiTexName);
float[] histR = new float[256];
float[] histG = new float[256];
float[] histB = new float[256];
// TODO: cache tag thresholds and only recalculate when dirty (otherwise many tags will impeede performance)
if (tags.Count > 0)
{
// Rectangle localRoiRect = new Rectangle (0, 0, roiRect.Width, roiRect.Height);
int sampleWidth = 100;
int pixelCount = sampleWidth * sampleWidth;
byte[] pixels = new byte[pixelCount * 4];
foreach (Tag tag in tags)
{
if (tag.calculateThreshold)
{
tag.calculateThreshold = false;
Rectangle sampleRect = tag.ThresholdSampleRect;
Point loc = sampleRect.Location;
loc.Offset(-roiRect.Location.X, -roiRect.Location.Y);
sampleRect.Location = loc;
// sampleRect = Rectangle.Intersect(tagRect, localRoiRect);
// Skip rects outside roi
if (sampleRect.Width == 0 || sampleRect.Height == 0)
{
continue;
}
// Clear histograms
for (int i = 0; i < 256; i++)
{
histR [i] = 0;
histG [i] = 0;
histB [i] = 0;
}
// Read pixels
GL.ReadPixels(sampleRect.Left, sampleRect.Top, sampleRect.Width, sampleRect.Height, PixelFormat.Rgba, PixelType.UnsignedByte, pixels);
// Get color of tag (center of sample)
int pxIdx = pixelCount * 2 + sampleRect.Width * 2;
tag.Color [0] = pixels [pxIdx] & 0xff;
tag.Color [1] = pixels [pxIdx + 1] & 0xff;
tag.Color [2] = pixels [pxIdx + 2] & 0xff;
// Get histogram for pixels around tag
int count = pixelCount * 4;
int j = 0;
while (j < count)
{
int iR = pixels [j++] & 0xff;
int iG = pixels [j++] & 0xff;
int iB = pixels [j++] & 0xff;
int iA = pixels [j++] & 0xff;
if (iA > 0)
{
histR [iR]++;
histG [iG]++;
histB [iB]++;
}
}
// Fill gaps in threshold to prepare it for threshold finding
Histogram.FillGaps(histR);
Histogram.FillGaps(histG);
Histogram.FillGaps(histB);
// Find threshold
tag.Threshold [0] = OtsuThreshold.getThreshold(histR);
tag.Threshold [1] = OtsuThreshold.getThreshold(histG);
tag.Threshold [2] = OtsuThreshold.getThreshold(histB);
}
}
}
// unbind framebuffer and cleanup viewport
GL.BindFramebuffer(FramebufferTarget.Framebuffer, fboOld);
GL.Viewport(oldViewPort[0], oldViewPort[1], oldViewPort[2], oldViewPort[3]);
}
public static void GetROIThreshold(Rectangle rect, uint[] pixelBuffer, int[] min, int[] max, uint frameBuffer, uint roiTexName)
{
// Setup viewport
int[] oldViewPort = new int[4];
GL.GetInteger(GetPName.Viewport, oldViewPort);
GL.Viewport(0, 0, rect.Size.Width, rect.Size.Height);
int fboOld = GLHelper.bindFrameBuffer(frameBuffer, roiTexName);
// Update ROI histogram
// TODO: use already allocated segmentation buffer
{
float[] histR = new float[256];
float[] histG = new float[256];
float[] histB = new float[256];
int pixelCount = rect.Width * rect.Height;
byte[] pixels = new byte[pixelCount * 4];
GL.ReadPixels(0, 0, rect.Width, rect.Height, PixelFormat.Rgba, PixelType.UnsignedByte, pixels);
int count = pixelCount * 4;
int j = 0;
int sumR = 0, sumG = 0, sumB = 0;
int sampleCount = 0;
while (j < count)
{
int iR = pixels [j++] & 0xff;
int iG = pixels [j++] & 0xff;
int iB = pixels [j++] & 0xff;
int iA = pixels [j++] & 0xff;
if (iA > 0)
{
sampleCount++;
sumR += iR;
sumG += iG;
sumB += iB;
histR [iR]++;
histG [iG]++;
histB [iB]++;
}
}
float avrR = (float)sumR / (float)sampleCount;
// float avrG = (float)sumG/(float)sampleCount;
// float avrB = (float)sumB/(float)sampleCount;
Histogram.FillGaps(histR);
Histogram.FillGaps(histG);
Histogram.FillGaps(histB);
// Find threshold
int thresholdR = OtsuThreshold.getThreshold(histR);
int thresholdG = OtsuThreshold.getThreshold(histG);
int thresholdB = OtsuThreshold.getThreshold(histB);
if (avrR > thresholdR)
{
min[0] = 0;
min[1] = 0;
min[2] = 0;
max[0] = thresholdR;
max[1] = thresholdG;
max[2] = thresholdB;
}
else
{
min[0] = thresholdR;
min[1] = thresholdG;
min[2] = thresholdB;
max[0] = 1;
max[1] = 1;
max[2] = 1;
}
}
// unbind framebuffer
GL.BindFramebuffer(FramebufferTarget.Framebuffer, fboOld);
GL.Viewport(oldViewPort[0], oldViewPort[1], oldViewPort[2], oldViewPort[3]);
}
