mmhistogram - Find the histogram of the image f.

Output: h: Gray-scale (uint8 or uint16) image. Histogram in a uint16 column vector.

Description: Finds the histogram of the image f and returns the result in the column vector h. For binary image the vector size is 2, for gray-scale uint8 and uint16 images, the vector size is the maximum pixel value plus one. h(1) gives the number of pixels with value 0.

Limitation: Be aware that the maximum value in the output vector is 65535. There are images where a specific gray value can appear a number larger than this value.

Examples

f=uint8([0 1 1 2 2 2 5 3 5]);
h=mmhistogram(f);
h'

ans =
     1     2     3     1     0     2

f=mmreadgray('lenina.tif');
mmshow(f);
h=mmhistogram(f);
plot(h);

(f)

(h)

Algorithm

function h = mmhistogram_equ(f)
  m=max(f(:));
  h=zeros(m+1,1);
  for i=1:m+1
    h(i)=length(find(f==(i-1)));
  end

See Also: mmblob - Blob measurements from a labeled image.; mmfreedom - Control automatic data type conversion.

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