void DrawHistogram(PictureBox window, CVHistogram histo, int channelIdx)
{
int imageWidth = window.Width;
int imageHeight = window.Height;
int bins = histo.BinSizes[0];
int binWidth = imageWidth / bins;
if (binWidth <= 0) binWidth = 1;
CVPair minMax = histo.MinMaxValue;
CVImage outputImage = new CVImage(imageWidth, imageHeight, CVDepth.Depth8U, 3);
outputImage.Zero();
for (int bin = 0; bin < bins; bin++)
{
double binValue = histo[bin];
byte level = (byte)CVUtils.Round(binValue * 255 / minMax.Second);
byte binHeight = (byte)CVUtils.Round(binValue * imageHeight / minMax.Second);
byte[] color = new byte[3];
color[channelIdx] = (byte) (((double) bin / (double) bins) * 255);
byte[] markerColor = new byte[3];
markerColor[channelIdx] = level;
Color colColor = Color.FromArgb(color[2], color[1], color[0]);
Color colMarker = Color.FromArgb(markerColor[2], markerColor[1], markerColor[0]);
outputImage.DrawRectangle(new Rectangle(bin * binWidth, imageHeight - binHeight, binWidth - 1, binHeight), colColor);
outputImage.DrawRectangle(new Rectangle(bin * binWidth, imageHeight - binHeight, binWidth - 1, binHeight), colMarker);
outputImage.DrawRectangle(new Rectangle(bin * binWidth, imageHeight - binHeight, 1, binHeight), colMarker);
}
window.Image = outputImage.ToBitmap();
outputImage.Release();
}
private void UpdateHistogram()
{
int numberOfBins;
if (!int.TryParse(binSize.Text, out numberOfBins))
{
statusBar.Text = string.Format("Number of bins '{0}' is not an integer.", binSize.Text);
return;
}
if (image == null) return;
//image.RegionOfInterest = originalImage.SelectionRect;
// split image into channels (b,g,r)
CVImage[] planes = image.Split();
// we will create a 1D histogram for every channel. each histogram will have
// 'numberOfBins' bins for its single dimension (ranged from 0 to 255).
int[] bins = { numberOfBins };
CVPair[] ranges = { new CVPair(0, 255) };
// calculate histogram for red, green and blue channels (seperately).
CVHistogram histoRed = planes[0].CalcHistogram(bins, ranges);
CVHistogram histoBlue = planes[1].CalcHistogram(bins, ranges);
CVHistogram histoGreen = planes[2].CalcHistogram(bins, ranges);
// draw the three histograms.
DrawHistogram(bluePanel, histoBlue, 1);
DrawHistogram(greenPanel, histoGreen, 2);
DrawHistogram(redPanel, histoRed, 0);
// resize & put original image onto form.
CVImage output = new CVImage(image.Width, image.Height, CVDepth.Depth8U, 3);
CVImage emptyPlane = new CVImage(image.Width, image.Height, CVDepth.Depth8U, 1);
emptyPlane.Zero();
CVImage[] images = new CVImage[3];
images[0] = images[1] = images[2] = emptyPlane;
if (blueCheck.Checked) images[0] = planes[0];
if (greenCheck.Checked) images[1] = planes[1];
if (redCheck.Checked) images[2] = planes[2];
output.Merge(images);
originalImage.Image = output.ToBitmap();
// dispose of plane images.
foreach (CVImage img in planes)
img.Dispose();
statusBar.Text = "Ready";
}