MATLAB学习笔记 学习总结归纳(第二周)

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本次学习内容为第6章

这周复习了上一周所学的内容,顽固加深理解以后,学习了第6章前半部分。


MATLAB中的彩色图像的表示(图像格式)

RGB图像

所谓RGB图像,即为R(Red 红) G(Green绿) B(Blue蓝) 的灰度图(三个长宽一样的二维矩阵)组成的图像比如以下这段代码

r = zeros(300, 300);g = zeros(300, 300);b = zeros(300, 300);r(1:100, 1:100) = 1;g(101:200, 101:200) = 1;b(201:300, 201:300) = 1;img = cat(3, r, g, b); subplot(2, 2, 1), imshow(r), title('R'); subplot(2, 2, 2), imshow(g), title('G'); subplot(2, 2, 3), imshow(b), title('B'); subplot(2, 2, 4), imshow(img), title('RGB');
  • 输入:
    这里写图片描述
  • 输出:
    这里写图片描述

可以看出 其实RGB 三张分别代表红绿蓝的灰度图 叠加在一起的图像。

索引图像

索引图像有两个分量: 一个整数数据矩阵X 和 一个彩色银蛇矩阵map。矩阵map是一个大小为m*3的double类数组,其值是区间[0, 1]上的浮点数。map的长度m等于其定义的颜色的个数。map存的是RGB三个分量。

f  = imread('onion.png');[X, map] = rgb2ind(f, 2);[X2, map2] = rgb2ind(f, 256);[X3, map3] = rgb2ind(f, 65535);subplot(2, 2, 1), imshow(f), title('原图');subplot(2, 2, 2), imshow(X, map), title('索引图 2种颜色');subplot(2, 2, 3), imshow(X2, map2), title('索引图 256种颜色');subplot(2, 2, 4), imshow(X3, map3), title('索引图 65535种颜色');
  • 输入:
    这里写图片描述
  • 输出:
    这里写图片描述

处理RGB和索引图像的函数

* ind2rgb(X, map) 将索引图变为RGB图*

rgb2ind(image, n) 将RGB转为索引图,索引颜色数规定为n个,可以指定转换时运用什么方式进行颜色处理

有二种方式,一种为dither 抖动,另一种为nodither 不抖动。
抖动是什么意思呢,就是为了让图片看起来更加自然,每个像素的点会中和其邻域的点的颜色,这样就会显得这个点的像素颜色不那么突兀。

f = imread('onion.png');subplot(2, 3, 1), imshow(f), title('原图');subplot(2, 3, 4), bar([imhist(f(:, :, 1), 10), imhist(f(:, :, 2), 10), imhist(f(:, :, 3), 10)]), axis tight, title('原图的三色直方图');[X, map] = rgb2ind(f, 256); % 默认为dithersubplot(2, 3, 2), imshow(ind2rgb(X, map)), title('dither');f = ind2rgb(X, map);subplot(2, 3, 5), bar([imhist(f(:, :, 1), 10), imhist(f(:, :, 2), 10), imhist(f(:, :, 3), 10)]), axis tight, title('dither的三色直方图');[X, map] = rgb2ind(f, 256, 'nodither');subplot(2, 3, 3), imshow(ind2rgb(X, map)), title('nodither');f = ind2rgb(X, map);subplot(2, 3, 6), bar([imhist(f(:, :, 1), 10), imhist(f(:, :, 2), 10), imhist(f(:, :, 3), 10)]), axis tight, title('nodither的三色直方图');
  • 输入:
    这里写图片描述
  • 输出:
    这里写图片描述

dither(image) 该方法即为上面rgb2ind函数的dither方法,该函数处理灰度图效果最明显

f = imread('coins.png');g = dither(f);subplot(1, 2, 1), imshow(f), title('原图');subplot(1, 2, 2), imshow(g), title('抖动出来的二值图');
  • 输入:
    这里写图片描述
  • 输出:
    这里写图片描述

彩色空间转换

我们之前都是对RGB图像对彩色图像进行操作(间接或直接),很少用到其他的彩色空间,这章我们学习从RGB变换得到的彩色空间(彩色模型)。
这些彩色空间包括NTSC、YCbCr、HSV、CMY、CMYK、HSI。

NTSC彩色空间

NTSC彩色模型为模拟电视, 分为三个分量,YIQ ,分为别亮度,色调, 对比度(就是我们常常调自己家电视的亮度、色调、对比度),这个模型使得同一个信号,可以在彩色电视显示,也可以在黑白电视显示。

rgb2ntsc(image) 将RGB图像变换为NTSC

f = imread('onion.png');g = rgb2ntsc(f);subplot(1, 2, 1), imshow(f), title('RGB');subplot(1, 2, 2), imshow(g), title('NTSC');
  • 输入:
    这里写图片描述
  • 输出:
    这里写图片描述

ntsc2rgb(image) 将NTSC图像变换为RGB图像

f = imread('onion.png');g = rgb2ntsc(f);img = ntsc2rgb(g);subplot(1, 3, 1), imshow(f), title('原图');subplot(1, 3, 2), imshow(g), title('NTSC');subplot(1, 3, 3), imshow(img), title('RGB');
  • 输入:
    这里写图片描述
  • 输出:
    这里写图片描述

myRgb2ntsc(image) 自制的rgb2ntsc,将RGB变换NTSC格式

f = imread('onion.png');g = rgb2ntsc(f);img = myRgb2ntsc(f);subplot(1, 3, 1), imshow(f), title('原图');subplot(1, 3, 2), imshow(g), title('NTSC rgb2ntsc');subplot(1, 3, 3), imshow(img), title('NTSC myRgb2ntsc');
  • 输入:
    这里写图片描述
  • 输出:
    这里写图片描述

myNtsc2rgb(image) 自制的ntsc2rgb, 将NTSC变换为RGB

f = imread('onion.png');g = rgb2ntsc(f);img = myNtsc2rgb(g);subplot(1, 3, 1), imshow(f), title('原图');subplot(1, 3, 2), imshow(g), title('NTSC');subplot(1, 3, 3), imshow(img), title('RGB');
  • 输入:
    这里写图片描述
  • 输出:
    这里写图片描述

YCbCr彩色空间

YCbCr彩色模型用于数字视频中。模型分为3个分量,Y(亮度) Cb(蓝色分量和参数值的差) Cr(红色分量和参考值的差)

rgb2ycbcr(image) 将RGB图像转为YCbCr

f = imread('onion.png');g = rgb2ycbcr(f);subplot(1, 2, 1), imshow(f), title('原图');subplot(1, 2, 2), imshow(g), title('YCbCr');
  • 输入:
    这里写图片描述
  • 输出:
    这里写图片描述

ycbcr2rgb(image) 将YCbCr转为RGB

f = imread('onion.png');g = rgb2ycbcr(f);img = ycbcr2rgb(g);subplot(1, 3, 1), imshow(f), title('原图');subplot(1, 3, 2), imshow(g), title('YCbCr');subplot(1, 3, 3), imshow(img), title('RGB');
  • 输入:
    这里写图片描述
  • 输出:
    这里写图片描述

HSV彩色空间

HSV分别代表色调、饱和度、数值,该模型更加贴近人们的经验和描述彩色感觉时所采用的方式,在艺术领域,称为色泽、明暗、调色。

rgb2hsv(image) 将RGB转为HSV

f = imread('onion.png');g = rgb2hsv(f);subplot(1, 2, 1), imshow(f), title('原图');subplot(1, 2, 2), imshow(g), title('HSV');
  • 输入:
    这里写图片描述
  • 输出:
    这里写图片描述

**hsv2rgb(image) 将HSV转为RGB

f = imread('onion.png');g = rgb2hsv(f);img = hsv2rgb(g);subplot(1, 3, 1), imshow(f), title('原图');subplot(1, 3, 2), imshow(g), title('hsv');subplot(1, 3, 3), imshow(img), title('RGB');
  • 输入:
    这里写图片描述
  • 输出:
    这里写图片描述

CMY和CMYK彩色空间

该模型常常用于彩色打印。
CMY模型分为三个分量,C 青色(Cyan)、M 深红色(Magenta)、Y 黄色(Yellow)。
CMYK则是在CMY上加一个黑色

imcomplement(image) 获取图片负片, 可以实现CMY模型与RGB互换

f = imread('onion.png');g = imcomplement(f);img = imcomplement(g);subplot(1, 3, 1), imshow(f), title('原图');subplot(1, 3, 2), imshow(g), title('CMY');subplot(1, 3, 3), imshow(img), title('RGB');
  • 输入:
    这里写图片描述
  • 输出:
    这里写图片描述

HSI彩色空间

HSI模型三个分量为, H 色彩(hue), S 饱和度(saturation), I 强度(intensity)

rgb2hsi(image) 将rgb图像转为hsi图像

f = imread('onion.png');g = rgb2hsi(f);subplot(1, 2, 1), imshow(f), title('原图');subplot(1, 2, 2), imshow(g), title('HSI');
  • 输入:
    这里写图片描述
  • 输出:
    这里写图片描述

hsi2rgb(image) 将hsi图像变换为rgb图像

f = imread('onion.png');g = rgb2hsi(f);img = hsi2rgb(g);subplot(1, 3, 1), imshow(f), title('原图');subplot(1, 3, 2), imshow(g), title('HSI');subplot(1, 3, 3), imshow(img), title('RGB');
  • 输入:
    这里写图片描述
  • 输出:
    这里写图片描述

附录

小实验

HSV与HSI图像显示比较

f = imread('onion.png');subplot(1, 3, 1), imshow(f), title('原图');subplot(1, 3, 2), imshow(rgb2hsi(f)), title('HSI');subplot(1, 3, 3), imshow(rgb2hsv(f)), title('HSV');
  • 输入:
    这里写图片描述
  • 输出:
    这里写图片描述
    可以看出HSI与HSV的图像有一些差别,HSI偏深,HSV偏浅,再看一下这二个模型的三个分量
f = imread('onion.png');subplot(2, 3, 1), imshow(f), title('原图');subplot(2, 3, 2), imshow(rgb2hsi(f)), title('HSI');subplot(2, 3, 3), imshow(rgb2hsv(f)), title('HSV');subplot(2, 3, 4), sBar(f, 10), title('原图'), xlabel('R红 G绿 B蓝');subplot(2, 3, 5), sBar(rgb2hsi(f), 10), title('HSI'), xlabel('H色彩 S饱和度 I强度');subplot(2, 3, 6), sBar(rgb2hsv(f), 10), title('HSV'), xlabel('H色调 S饱和度 I数值');
  • 输入:
    这里写图片描述
  • 输出:
    这里写图片描述
    主要看第HSI和HSV图,可以看出,色调(H)基本相同,饱和度(S)是有差距的,强度与数值的差距巨大。所以HSI与HSV是不同的,如果只是想要调整色调,则无所谓,但是在调节数值和强度的时候,就需要好好琢磨了。

myHisteq(image) 对彩色图像进行直方图均衡化

f = imread('onion.png');g = myHisteq(f, 'hsv');p = myHisteq(f, 'rgb');subplot(2, 3, 1), imshow(f), title('原图');subplot(2, 3, 2), imshow(g), title('仅对HSV的V通道进行均衡化后');subplot(2, 3, 3), imshow(p), title('对RGB通道进行均衡化后');subplot(2, 3, 4), sBar(f, 25), title('原图');subplot(2, 3, 5), sBar(g, 25), title('仅对HSV的V通道进行均衡化后');subplot(2, 3, 6), sBar(p, 25), title('对RGB通道进行均衡化后');
  • 输入:
    这里写图片描述
  • 输出:
    这里写图片描述

clahe(image) 对比度受限的自适应直方图均衡化

本小实验主要看一下自制的clahe、工具箱中的adapthisteq、和利用imadjust进行灰度变换去雾的差别

f = imread('大雾.jpg');g1 = clahe(f);g2 = quwu(f);g3 = cat(3, adapthisteq(f(:, :, 1)), adapthisteq(f(:, :, 2)), adapthisteq(f(:, :, 3)));subplot(2, 4, 1), imshow(f), title('原图');subplot(2, 4, 2), imshow(g1), title('CLAHE');subplot(2, 4, 3), imshow(g2), title('imadjust');subplot(2, 4, 4), imshow(g3), title('adapthisteq');subplot(2, 4, 5), sBar(f, 10), title('原图');subplot(2, 4, 6), sBar(g1, 10), title('CLAHE');subplot(2, 4, 7), sBar(g2, 10), title('imadjust');subplot(2, 4, 8), sBar(g3, 10), title('adapthisteq');
  • 输入:
    这里写图片描述
  • 输出:
    这里写图片描述
    可以看出去雾效果还是很明显的,imadjust的话,还是有很多雾点没有去除,adapthisteq和clahe的话相对好一些。

代码

myRgb2ntsc.m

function img = myRgb2ntsc(f)    f = im2double(f);    d =  [0.229, 0.587, 0.114; 0.596, -0.274, -0.332; 0.211, -0.523, 0.312] ;    r = f(:, :, 1);    g = f(:, :, 2);    b = f(:, :, 3);    y = r * d(1, 1) + g * d(1, 2) + b * d(1, 3);    i = r * d(2, 1) + g * d(2, 2) + b * d(2, 3);    q = r * d(3, 1) + g * d(3, 2) + b * d(3, 3);    img = cat(3, y, i, q);end

myNtsc2rgb.m

function img = myNtsc2rgb(f)    f = im2double(f);    d =  [1.0, 0.956, 0.621; 1.0, -0.272, -0.647; 1.0, -1.106, 1.703];    y = f(:, :, 1);    i = f(:, :, 2);    q = f(:, :, 3);    r = y * d(1, 1) + i * d(1, 2) + q * d(1, 3);    g = y * d(2, 1) + i * d(2, 2) + q * d(2, 3);    b = y * d(3, 1) + i * d(3, 2) + q * d(3, 3);    img = cat(3, r, g, b);end

rgb2hsi.m

function hsi = rgb2hsi(image)    rgb = im2double(image);    r = rgb(:, :, 1);    g = rgb(:, :, 2);    b = rgb(:, :, 3);    num = 0.5 * ((r - g) + (r - b));    den = sqrt((r - g) .^ 2 + (r - b) .* (g - b));    theta = acos(num ./ (den + eps));    H = theta;    H(b > g) = 2 * pi - H(b > g);    H = H / (2 * pi);    num = min(min(r, g), b);    den = r + g + b;    den(den == 0) = eps;    S = 1 - 3 .* num ./ den;    H(S == 0) = 0;    I = (r + g + b) / 3;    hsi = cat(3, H, S, I);end

hsi2rgb.m

function rgb = hsi2rgb(hsi)    H = hsi(:, :, 1) * 2 * pi;    S = hsi(:, :, 2);    I = hsi(:, :, 3);    width = size(hsi, 1);    height =  size(hsi, 2);    R = zeros(width, height);    G = zeros(width, height);    B = zeros(width, height);    idx = find(0 <= H < 2 * pi / 3);    B(idx) = I(idx) .* (1 - S(idx));    R(idx) = I(idx) .* (1 + S(idx) .* cos(H(idx)) ./ cos(pi / 3 - H(idx)));    G(idx) = 3 * I(idx) - (R(idx) + B(idx));    idx = find((2 * pi / 3 <= H & H < 4 * pi / 3));    R(idx) = I(idx) .* (1 - S(idx));    G(idx) = I(idx) .* (1 + S(idx) .* cos(H(idx) - 2 * pi / 3) ./ cos(pi - H(idx)));    B(idx) = 3 * I(idx) - (R(idx) + G(idx));    idx = find((4 * pi / 3 <= H) & (H <= 2 * pi));    G(idx) = I(idx) .* (1 - S(idx));    B(idx) = I(idx) .* (1 + S(idx) .* cos(H(idx) - 4 * pi / 3) ./ cos(5 * pi / 3 - H(idx)));    R(idx) = 3 * I(idx) - (G(idx) + B(idx));    rgb = cat(3, R, G, B);    rgb = max(min(rgb, 1), 0);end

sBar.m

function sBar(data, varargin)    if ndims(data) == 3        if nargin() == 1            b = bar([imhist(data(:, :, 1)) imhist(data(:, :, 2)) imhist(data(:, :, 3))]);        elseif nargin() == 2            b = bar([imhist(data(:, :, 1), varargin{1}) imhist(data(:, :, 2), varargin{1}) imhist(data(:, :, 3), varargin{1})]);        end    elseif ndims(data) == 2        b = bar(imhist(data));    elseif ndims(data) == 1        b = bar(data)    else        error '错误的输入';    end    axis tight;    color=['r', 'g', 'b'];    for i=1:3        set(b(i),'FaceColor',color(i));    endend

myHisteq.m

function img = myHisteq(f, varargin)% 对彩色图像进行均衡化% 可以传入的图片为灰度图,RGB,索引图% g = myHisteq(img);% g = myHisteq(X, map);    if numel(varargin) == 1        type = getImageType(f, varargin);    else         type = getImageType(f);    end    if strcmp(type,'RGB图') == 1        p = rgb2hsv(f); % 对HSV 的 V 通道进行处理(原图不会失真)        img = cat(3, p(:,:,1) .* 256, p(:,:,2) .* 256, myHisteq(uint8(p(:,:,3) .* 256)));        img = hsv2rgb(tofloat(img));    elseif strcmp(type,'索引图') == 1        img = myHisteq(ind2rgb(f, varargin));    else        [height, width] = size(f);        numPixel = zeros(1, 256);        for i=1:height            for j=1:width                numPixel(f(i, j) + 1) = numPixel(f(i, j) + 1) + 1;            end        end        probPixel = numPixel ./ (height * width);        cumuPixel = cumsum(probPixel);        cumuPixel = uint8(256 .* (cumuPixel + 0.1));        img = cumuPixel(f(:,:) + 1);    endend

quwu.m

function quwu(f, varargin)% QUWU% 使用imadjust 和 stretchlim 进行简单的去雾 % quwu(f)% quwu(f, 0.1)% quwu(f, 0.95);% 第二,第三个参数分别为stretchlim的TOL的Low High    r = f(:,:,1);    g = f(:,:,2);    b = f(:,:,3);    if nargin == 1        low = 0;        high = 1;    elseif nargin == 2        if isfloat(varargin{1}) && varargin{1} >= 0 && varargin{1} <= 1            low = varargin{1};        else            error '第二个参数必须为小数([0, 1])';        end        high = 1;    elseif nargin == 3        if isfloat(varargin{1}) && varargin{1} >= 0 && varargin{1} <= 1            low = varargin{1};        else            error '第二个参数必须为小数([0, 1])';        end        if isfloat(varargin{2}) && varargin{2} >= 0 && varargin{2} <= 1            high = varargin{2};        else            error '第三个参数必须为小数([0, 1])';        end    else        error '传入参数个数错误';    end    Low_High = stretchlim(r, [low high]);    rr = imadjust(r, Low_High, []);    Low_High = stretchlim(g, [low high]);    gg = imadjust(g, Low_High, []);    Low_High = stretchlim(b, [low high]);    bb = imadjust(b, Low_High, []);    l = cat(3, rr, gg, bb);    imshow(l);    subplot(1, 2, 1), imshow(f);    subplot(1, 2, 2), imshow(l);end

CLAHE

以下函数除了clahe, 其他都为网上的资源

clipHistogram.m
function [Hist] = clipHistogram(Hist,NrBins,ClipLimit,NrX,NrY)%  This function performs clipping of the histogram and redistribution of bins.%  The histogram is clipped and the number of excess pixels is counted. Afterwards%  the excess pixels are equally redistributed across the whole histogram (providing%  the bin count is smaller than the cliplimit).for i = 1:NrX    for j = 1:NrY        %   Calculate the total number of excess pixels.        NrExcess = 0;        for nr = 1:NrBins            excess=Hist(i,j,nr) - ClipLimit;            if excess > 0                NrExcess = NrExcess + excess;            end        end        %  Clip histogram and redistribute excess pixels in each bin        binIncr = NrExcess / NrBins;        upper = ClipLimit - binIncr;        for nr = 1:NrBins            if Hist(i,j,nr) > ClipLimit                Hist(i,j,nr) = ClipLimit;            else                if Hist(i,j,nr) > upper                    NrExcess = NrExcess + upper - Hist(i,j,nr);                    Hist(i,j,nr) = ClipLimit;                else                    NrExcess = NrExcess - binIncr;                    Hist(i,j,nr) = Hist(i,j,nr) + binIncr;                end            end        end        if NrExcess > 0            stepSize = max(1,fix(1+NrExcess/NrBins));            for nr = 1:NrBins                NrExcess = NrExcess - stepSize;                Hist(i,j,nr) = Hist(i,j,nr) + stepSize;                if NrExcess < 1                    break;                end            end        end    endend
interpolate.m
function [subImage] = interpolate(subBin,LU,RU,LB,RB,XSize,YSize)%  pImage      - pointer to input/output image%  uiXRes      - resolution of image in x-direction%  pulMap*     - mappings of greylevels from histograms%  uiXSize     - uiXSize of image submatrix%  uiYSize     - uiYSize of image submatrix%  pLUT        - lookup table containing mapping greyvalues to bins%  This function calculates the new greylevel assignments of pixels within a submatrix%  of the image with size uiXSize and uiYSize. This is done by a bilinear interpolation%  between four different mappings in order to eliminate boundary artifacts.%  It uses a division; since division is often an expensive operation, I added code to%  perform a logical shift instead when feasible.% subImage = zeros(size(subBin));num = XSize * YSize;for i = 0:XSize-1    inverseI = XSize - i;    for j = 0:YSize-1        inverseJ = YSize - j;        val = subBin(i+1,j+1);        subImage(i+1,j+1) = fix((inverseI*(inverseJ*LU(val) + j*RU(val)) ...             + i*(inverseJ*LB(val) + j*RB(val)))/num);    endend
mapHistogram.m
function [Map] = mapHistogram(Hist,Min,Max,NrBins,NrPixels,NrX,NrY)%  This function calculates the equalized lookup table (mapping) by%  cumulating the input histogram. Note: lookup table is rescaled in range [Min..Max].Map=zeros(NrX,NrY,NrBins);Scale = (Max - Min)/NrPixels;for i = 1:NrX    for j = 1:NrY        Sum = 0;        for nr = 1:NrBins            Sum = Sum + Hist(i,j,nr);            Map(i,j,nr) = fix(min(Min + Sum*Scale,Max));        end    endend
makeLUT.m
function [LUT] = makeLUT(Min,Max,NrBins)%  To speed up histogram clipping, the input image [Min,Max] is scaled down to%  [0,uiNrBins-1]. This function calculates the LUT.Max1 = Max + max(1,Min) - Min;Min1 = max(1,Min);BinSize = fix(1 + (Max - Min)/NrBins);LUT = zeros(fix(Max - Min),1);for i=Min1:Max1    LUT(i) = fix((i - Min1)/BinSize);end
makeHistogram.m
%  This function classifies the greylevels present in the array image into%  a greylevel histogram. The pLookupTable specifies the relationship%  between the greyvalue of the pixel (typically between 0 and 4095) and%  the corresponding bin in the histogram (usually containing only 128 bins).Hist=zeros(NrX,NrY,NrBins);for i=1:NrX    for j=1:NrY        bin=Bin(1+(i-1)*XSize:i*XSize,1+(j-1)*YSize:j*YSize);        for i1=1:XSize            for j1=1:YSize                Hist(i,j,bin(i1,j1)) = Hist(i,j,bin(i1,j1)) + 1;            end        end    endend
clahe.m
function output = clahe(Img, varargin)    ClipLimit = 1.75;    if numel(varargin) == 1        ClipLimit = varargin{1};    end    type = getImageType(Img);    if strcmp(type,'RGB图') == 1        output = cat(3, clahe(Img(:,:,1)), clahe(Img(:,:,2)), clahe(Img(:,:,3)));    else        [h,w] = size(Img);        output = zeros(h, w);        output = padarray(output, [5, 5], 'both');        minV = double(min(min(Img)));        maxV = double(max(max(Img)));        NrX = 8;        NrY = 4;        HSize = ceil(h/NrY);        WSize = ceil(w/NrX);        deltay = NrY*HSize - h;        deltax = NrX*WSize - w;        tmpImg = zeros(h+deltay,w+deltax);        tmpImg(1:h,1:w) = Img;        new_w = w + deltax;        new_h = h + deltay;        NrPixels = WSize * WSize;        NrBins = 256;        LUT = zeros(maxV+1,1);        for i=minV:maxV            LUT(i+1) = fix(i - minV);%i+1        end        Bin = zeros(new_h, new_w);        for m = 1 : new_h            for n = 1 : new_w                Bin(m,n) = 1 + LUT(tmpImg(m,n) + 1);            end        end        Hist = zeros(NrY, NrX, 256);        for i=1:NrY            for j=1:NrX                tmp = uint8(Bin(1+(i-1)*HSize:i*HSize, 1+(j-1)*WSize:j*WSize));                [Hist(i, j, :), x] = imhist(tmp, 256);            end        end        Hist = circshift(Hist,[0, 0, -1]);        ClipLimit = max(1,ClipLimit * HSize * WSize/NrBins);        Hist = clipHistogram(Hist,NrBins,ClipLimit,NrY,NrX);        Map=mapHistogram(Hist, minV, maxV, NrBins, NrPixels, NrY, NrX);        yI = 1;        for i = 1:NrY+1            if i == 1                subY = floor(HSize/2);                yU = 1;                yB = 1;            elseif i == NrY+1                subY = floor(HSize/2);                yU = NrY;                yB = NrY;            else                subY = HSize;                yU = i - 1;                yB = i;            end            xI = 1;            for j = 1:NrX+1                if j == 1                    subX = floor(WSize/2);                    xL = 1;                    xR = 1;                elseif j == NrX+1                    subX = floor(WSize/2);                    xL = NrX;                    xR = NrX;                else                    subX = WSize;                    xL = j - 1;                    xR = j;                end                UL = Map(yU,xL,:);                UR = Map(yU,xR,:);                BL = Map(yB,xL,:);                BR = Map(yB,xR,:);                subImage = Bin(yI:yI+subY-1,xI:xI+subX-1);                sImage = zeros(size(subImage));                num = subY * subX;                for i = 0:subY - 1                    inverseI = subY - i;                    for j = 0:subX - 1                        inverseJ = subX - j;                        val = subImage(i+1,j+1);                        sImage(i+1, j+1) = (inverseI*(inverseJ*UL(val) + j*UR(val)) ...                            + i*(inverseJ*BL(val) + j*BR(val)))/num;                    end                end                output(yI:yI+subY-1, xI:xI+subX-1) = sImage;                xI = xI + subX;            end            yI = yI + subY;        end        output = uint8(output(1:h, 1:w));    endend
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