Question

我获得了灰度图像，我想从中创建渐变幅度图像。我知道有一个名为pig -x local -4 nolog.conf的函数，但我不知道如何修改幅度，以便按以下方式计算：

imgradient

Answer 1

您必须实现自己的渐变功能，并将其应用于图像I中的每个像素：

//example of a 4x5 image I
I = [1 3 2 6 5; 6 1 0 18 21; 13 12 13 14 11; 16 15 28 9 20]

G = I; //set your gradient matrix to be equal to I so that the sides have a value

//get the height and width of image I
[h, w] = size(I);

//loop through each pixel that is not on the side
for x=2:w-1
   for y=2:h-1
      //for each pixel:
      z1 = I(y-1, x-1); //e.g z1 is the pixel on the upper left
      z2 = I(y, x-1);
      z3 = I(y+1, x-1);
      z4 = I(y-1, x);
      z6 = I(y+1, x);
      z7 = I(y-1, x+1);
      z8 = I(y, x+1);
      z9 = I(y+1, x+1);
      G(y,x) =  abs(z7+ 2*z8+ z9- z1- 2*z2- z3) + abs(z3+ 2*z6+ z9- z1- 2*z4- z7);
   end    
end

Answer 2

我知道您希望使用sobel掩码进行空间滤波（根据您的等式）。所以，我建议你使用以下命令：BW = edge（I，'Sobel'）;

或者如果你想按照你给出的等式输出精确的输出，那么试试这个：

I = imread('cameraman.tif');
I = padarray(I,[1 1],'symmetric');
sobel_mask_x = [-1 -2 -1; 0 0 0; 1 2 1];
sobel_x = filter2(sobel_mask_x ,I);
sobel_mask_y = sobel_mask_x';
sobel_y = filter2(sobel_mask_y ,I);
sobel_responce = abs(sobel_x)+abs(sobel_y);
figure,imshow(sobel_responce,[]); title('Sobel gradient');

这比使用for循环更快。

如何在MATLAB中创建梯度幅度图像

2 个答案: