public static Array GetHistogramOfImage(Mat image, char channel = 'b', int size = 256, float range = 256)
{
if (image == null)
{
return(null);
}
Mat hist = new Mat();
using (Emgu.CV.Util.VectorOfMat vm = new Emgu.CV.Util.VectorOfMat())
{
int[] histoChannel = { 0 };
if (channel == 'b')
{
histoChannel = new int[] { 0 }
}
;
if (channel == 'g')
{
histoChannel = new int[] { 1 }
}
;
if (channel == 'r')
{
histoChannel = new int[] { 2 }
}
;
int[] histoSize = { size };
float[] histoRange = { 0.0f, range };
vm.Push(image);
CvInvoke.CalcHist(vm, histoChannel, null, hist, histoSize, histoRange, false);
//CvInvoke.Normalize(hist, hist, 0, image.Rows, NormType.MinMax);
}
return(hist.GetData().Cast <float>().ToArray());
}
/// <summary>
/// Generate histograms for the image. One histogram is generated for each color channel.
/// You will need to call the Refresh function to do the painting afterward.
/// </summary>
/// <param name="image">The image to generate histogram from</param>
/// <param name="numberOfBins">The number of bins for each histogram</param>
public void GenerateHistograms(IImage image, int numberOfBins)
{
Mat[] channels = new Mat[image.NumberOfChannels];
Type imageType;
if ((imageType = Toolbox.GetBaseType(image.GetType(), "Image`2")) != null ||
(imageType = Toolbox.GetBaseType(image.GetType(), "Mat")) != null ||
(imageType = Toolbox.GetBaseType(image.GetType(), "UMat")) != null)
{
for (int i = 0; i < image.NumberOfChannels; i++)
{
Mat channel = new Mat();
CvInvoke.ExtractChannel(image, channel, i);
channels[i] = channel;
}
}
else if ((imageType = Toolbox.GetBaseType(image.GetType(), "CudaImage`2")) != null)
{
IImage img = imageType.GetMethod("ToImage").Invoke(image, null) as IImage;
for (int i = 0; i < img.NumberOfChannels; i++)
{
Mat channel = new Mat();
CvInvoke.ExtractChannel(img, channel, i);
channels[i] = channel;
}
}
else
{
throw new ArgumentException(String.Format("The input image type of {0} is not supported", image.GetType().ToString()));
}
Type[] genericArguments = imageType.GetGenericArguments();
String[] channelNames;
Color[] colors;
Type typeOfDepth;
if (genericArguments.Length > 0)
{
IColor typeOfColor = Activator.CreateInstance(genericArguments[0]) as IColor;
channelNames = Emgu.CV.Reflection.ReflectColorType.GetNamesOfChannels(typeOfColor);
colors = Emgu.CV.Reflection.ReflectColorType.GetDisplayColorOfChannels(typeOfColor);
typeOfDepth = imageType.GetGenericArguments()[1];
}
else
{
channelNames = new String[image.NumberOfChannels];
colors = new Color[image.NumberOfChannels];
for (int i = 0; i < image.NumberOfChannels; i++)
{
channelNames[i] = String.Format("Channel {0}", i);
colors[i] = Color.Red;
}
if (image is Mat)
{
typeOfDepth = CvInvoke.GetDepthType(((Mat)image).Depth);
}
else if (image is UMat)
{
typeOfDepth = CvInvoke.GetDepthType(((UMat)image).Depth);
}
else
{
throw new ArgumentException(String.Format("Unable to get the type of depth from image of type {0}", image.GetType().ToString()));
}
}
float minVal, maxVal;
#region Get the maximum and minimum color intensity values
if (typeOfDepth == typeof(Byte))
{
minVal = 0.0f;
maxVal = 256.0f;
}
else
{
#region obtain the maximum and minimum color value
double[] minValues, maxValues;
Point[] minLocations, maxLocations;
image.MinMax(out minValues, out maxValues, out minLocations, out maxLocations);
double min = minValues[0], max = maxValues[0];
for (int i = 1; i < minValues.Length; i++)
{
if (minValues[i] < min)
{
min = minValues[i];
}
if (maxValues[i] > max)
{
max = maxValues[i];
}
}
#endregion
minVal = (float)min;
maxVal = (float)max;
}
#endregion
for (int i = 0; i < channels.Length; i++)
{
//using (DenseHistogram hist = new DenseHistogram(numberOfBins, new RangeF(minVal, maxVal)))
using (Mat hist = new Mat())
using (Emgu.CV.Util.VectorOfMat vm = new Emgu.CV.Util.VectorOfMat())
{
vm.Push(channels[i]);
float[] ranges = new float[] { minVal, maxVal };
CvInvoke.CalcHist(vm, new int[] { 0 }, null, hist, new int[] { numberOfBins }, ranges, false);
//hist.Calculate(new IImage[1] { channels[i] }, true, null);
AddHistogram(channelNames[i], colors[i], hist, numberOfBins, ranges);
}
}
}
