matlab imhist description

%IMHIST Display histogram of N-D image data.
%   IMHIST(I) displays a histogram for the intensity image I whose number
%   of bins are specified by the image type.  If I is a grayscale image,
%   IMHIST uses 256 bins as a default value. If I is a binary image, IMHIST
%   uses only 2 bins. I can be 2-D, 3-D or N-D.
%
%   IMHIST(I,N) displays a histogram with N bins for the intensity image I
%   above a grayscale colorbar of length N.  If I is a binary image, then N
%   can only be 2.
%
%   IMHIST(X,MAP) displays a histogram for the indexed image X. This
%   histogram shows the distribution of pixel values above a colorbar of
%   the colormap MAP. The colormap must be at least as long as the largest
%   index in X. The histogram has one bin for each entry in the colormap.
%   X can be 2-D, 3-D or N-D.
%
%   [COUNTS,X] = imhist(...) returns the histogram counts in COUNTS and the
%   bin locations in X so that stem(X,COUNTS) shows the histogram. For
%   indexed images, it returns the histogram counts for each colormap
%   entry; the length of COUNTS is the same as the length of the colormap.
%
%   Class Support
%   -------------
%   An input intensity image can be uint8, int8, uint16, int16, uint32,
%   int32, single, double, or logical. An input indexed image can be uint8,
%   uint16, single, double, or logical. Both I and X can have any number of
%   dimensions.
%
%   Note
%   ----
%   For intensity images, the N bins of the histogram are each half-open
%   intervals of width A/(N-1).
%
%   For uint8, uint16, and uint32 intensity images, the p-th bin is the
%   half-open interval:
%
%        A*(p-1.5)/(N-1)  <= x  <  A*(p-0.5)/(N-1)
%
%   For int8, int16, and int32 intensity images, the p-th bin is the
%   half-open interval:
%
%        A*(p-1.5)/(N-1) - B  <= x  <  A*(p-0.5)/(N-1) - B
%
%   The intensity value is represented by "x". Intensity images of class
%   single and double are assumed to take values in [0 1]. The scale factor
%   A depends on the image class.  A is 1 if the intensity image is double
%   or single; A is 255 if the intensity image is uint8 or int8; A is 65535
%   if the intensity image is uint16 or int16; A is 4294967295 if the
%   intensity image is uint32 or int32. B is 128 if the image is int8; B is
%   32768 if the intensity image is int16; B is 2147483648 if the intensity
%   image is int32.
%   If the intensity values are complex numbers,the function takes the real
%   part and ignores the imaginary part.
%
%   Example 1
%   -------
%   % Display the histogram of a grayscale image.
%
%   I = imread('pout.tif');
%   imhist(I)
%
%   Example 2
%   -------
%   % Display the histogram of a 3-D intensity image.
%
%   load mristack
%   imhist(mristack)
%
%   See also HISTEQ, HISTOGRAM, IMHISTMATCH, IMHISTMATCHN.

%   Copyright 1992-2020 The MathWorks, Inc.