獲取matlab中圖像的中心像素

Question

我想提取圖像的大小爲(p*hight,p*width,3)的矩形區域。 p是[0,1]之間的雙倍值。

follwoing代碼的作品，但我想知道是否有更好的方法來實現這一目標？

img = imread(ImageName); 

% size parameter 
p = 0.5; 

% store image size 
hight = size(img,1); 
width = size(img,2); 

% calculate the center of the image both in width and hight 
% used as reference 
centerHight = floor(hight/2); 
centerWidth = floor(width/2); 

% use half of the actual size of the rectangular region 
halfHight = floor(p*hight/2); 
halfWidth = floor(p*width/2); 

% start index for hight and width 
startHight = 1 + centerHight - halfHight; 
startWidth = 1 + centerWidth - halfWidth; 

% end index for hight and width 
endHight = centerHight + halfHight; 
endWidth = centerWidth + halfWidth; 

% extract center pixels 
CenterPixels = img(startHight:endHight,startWidth:endWidth,:); 

是否有任何matlab命令獲得相同的結果？也許只需指定矩形和圖像中心的大小？

Answer 1

如果你有Image Processing toolbox，您可以使用imcrop功能和一些數學：

[nl, nc, ~] = size(img); 
CenterPixels = imcrop(img, [[nc nl] * (1 - p)/2 [nc nl] * p]); 

編輯：或者你可以做這樣的：

[nl, nc, ~] = size(img); 
CenterPixels = img(nl*(1-p)/2:nl*(1+p)/2, nc*(1-p)/2:nc*(1+p)/2, :);