MATLAB学习笔记 学习总结归纳(第二周)
2017-06-22 19:09
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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。
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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。
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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。
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这些彩色空间包括NTSC、YCbCr、HSV、CMY、CMYK、HSI。
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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
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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
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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。
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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。
[b]clipHistogram.m[/b]
[b]interpolate.m[/b]
[b]mapHistogram.m[/b]
[b]makeLUT.m[/b]
[b]makeHistogram.m[/b]
[b]clahe.m[/b]
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');
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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');
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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dither subplot(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');
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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');
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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');
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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');
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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');
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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');
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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');
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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');
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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');
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**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');
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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');
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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');
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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');
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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');
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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');
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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');
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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');
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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)); end end
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); end end
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[b]clipHistogram.m[/b]
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 end end
[b]interpolate.m[/b]
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); end end
[b]mapHistogram.m[/b]
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 end end
[b]makeLUT.m[/b]
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
[b]makeHistogram.m[/b]
% 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 end end
[b]clahe.m[/b]
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)); end end
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