图像中添加二项式分布噪声

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clc,clear,close allwarning offfeature jit offim = imread('coloredChips.png');Z0 = imnoise_B(im,size(im,1),size(im,2),0.5);Z1 = im2uint8(Z0);   % 类型转换figure('color',[1,1,1]),im(:,:,1) = im(:,:,1) + Z1;  % Rim(:,:,2) = im(:,:,2) + Z1;  % Gim(:,:,3) = im(:,:,3) + Z1;  % Bsubplot(121); imshow(im);title('加二项式分布噪声图像')subplot(122); imhist(Z1); title('加二项式分布噪声图像直方图')

function R = imnoise_B(im,M, N, b)% input:%       二项式B分布，噪声的类型；%       M,N：输出噪声图像矩阵的大小%       a,b：各种噪声的分布参数% output:%       R: 输出的噪声图像矩阵，数据类型为double型% 设定默认值% 考虑第floor(a/2)次命中if nargin < 4   b = 0.5;end   % 产生二项式分布噪声    for i = 1:M        for j=1:N           a = double( floor(im(i,j)/30)+1 );           R(i,j) = nchoosek(a,floor(a/2)) * b.^(floor(a/2)) .* (1-b).^(a- floor(a/2));        end    endend

nchoosek Binomial coefficient or all combinations

Syntax

C = nchoosek(n,k)

C = nchoosek(v,k)

Description

C = nchoosek(n,k) where n and k are nonnegative integers, returns n!/((n–k)! k!).
This is the number of combinations of n things taken k at a time.

C = nchoosek(v,k), where v is a row vector of length n, creates a matrix whose rows consist of all possible combinations of the n elements of v taken k at a time.

Matrix C contains n!/((n–k)! k!) rows and k columns.

Inputs n, k, and v support classes of float double and float single.

Examples

The command nchoosek(2:2:10,4) returns the even numbers from two to ten, taken four at a time:

      2     4     6     8
     2     4     6    10
     2     4     8    10
     2     6     8    10
     4     6     8    10

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