将直方图的 CDF 从 matlab 转换为 c#？

Question

如何将此 matlab 代码转换为 AForge.net+c# 代码？

cdf1 = cumsum(hist1) / numel(aa);

我发现 Accord.net 中存在 Histogram.cumulative 方法。但是不知道怎么用

请教如何转换。

% Histogram Matching
%

clear
clc
close all

pkg load image

% 이미지 로딩
aa=imread('2.bmp');
ref=imread('ref2.png');

figure(1); imshow(aa); colormap(gray)
figure(2); imshow(ref); colormap(gray)

M = zeros(256,1,'uint8'); % Store mapping - Cast to uint8 to respect data type
hist1 = imhist(aa); % Compute histograms
hist2 = imhist(ref);

cdf1 = cumsum(hist1) / numel(aa); % Compute CDFs
cdf2 = cumsum(hist2) / numel(ref);

% Compute the mapping
for idx = 1 : 256
[~,ind] = min(abs(cdf1(idx) - cdf2));


M(idx) = ind-1;
end

% Now apply the mapping to get first image to make
% the image look like the distribution of the second image
out = M(double(aa)+1);

figure(3); imshow(out); colormap(gray)

Answer 1

其实我对Accord.NET不是很了解，但是看了文档我觉得ImageStatisticsclass就是你要找的（reference here).问题是它不能为图像建立一个单一的直方图，你必须自己做。 imhist 在 Matlab 中只是合并三个通道，然后计算总像素出现次数，所以这是你应该做的：

Bitmap image = new Bitmap(@"C:\Path\To\Image.bmp");

ImageStatistics statistics = new ImageStatistics(image);
Double imagePixels = (Double)statistics.PixelsCount;

Int32[] histR = statistics.Red.Values.ToArray();
Int32[] histG = statistics.Green.Values.ToArray();
Int32[] histB = statistics.Blue.Values.ToArray();
Int32[] histImage = new Int32[256];

for (Int32 i = 0; i < 256; ++i)
    histImage[i] = histR[i] + histG[i] + histB[i];

Double cdf = new Double[256];
cdf[0] = (Double)histImage[0];

for (Int32 i = 1; i < 256; ++i)
    cdf[i] = (Double)(cdf[i] + cdf[i - 1]);

for (Int32 i = 0; i < 256; ++i)
    cdf[i] = cdf[i] / imagePixels;

在 C# 中，可以从 R、G 和 B 通道值构建 RGB 值，如下所示：

public static int ChannelsToRGB(Int32 red, Int32 green, Int32 blue)
{
    return ((red << 0) | (green << 8) | (blue << 16));
}

将直方图的 CDF 从 matlab 转换为 c#？

Converting CDF of histogram to c# from matlab?

c#

matlab

histogram

aforge

cdf