return matlab中索引图像的索引值

Question

我想在 Matlab 中从特定坐标 (X, Y) 的索引图像中提取索引值。

我使用了 impixel，它非常适合图像，但是，当我在循环中使用它时，它 returns NaN 或不正确的值。

 filename  = 'realworldCoordinates.txt';  % define the file name 
delimiterIn = '';  % set parameter for seperating values 
headerlinesIn = 1;   %which line is header

[A] = importdata (filename);

I = A.data (:,:);
X1 = II(:,1);  %define X1
Y1 = II(:,2);  % define Y1

X2 = II(:,3);  %define X2
Y2 = II(:,4);  %define Y2

for k = 1: numel (Imfiles(1:2))
    fileNames = Imfiles(k).name;
    imIndexed = imread (fileNames);
    Z1 = impixel (imIndexed(:,:,3), X1,Y1);
    Z2 = impixel (imIndexed(:,:,3), X2,Y2);         
    end

Answer 1

由于我没有你的完整代码，我只能假设一些关于正在发生的事情，而不能实际尝试这个解决方案来看看它是否能满足你的要求。首先，我不确定 impixel 是否应该支持仅传递您使用 imIndexed(:,:,3) 处理的每个像素的第三个元素，而是您应该在使用 impixel 后获得第三个元素。尝试做这样的事情：

for k = 1: numel (Imfiles(1:2))
    fileNames = Imfiles(k).name;
    imIndexed = imread (fileNames);
    tmp1 = impixel (imIndexed, X1,Y1);
    tmp2 = impixel (imIndexed, X2,Y2);
    Z1 = tmp1(3);
    Z2 = tmp2(3);
end

Answer 2

根据@mike Thomson 的建议，我将我的代码修改如下：

    filename  = 'realworldCoordinates.txt';  % define the file name 
    delimiterIn = '';  % set parameter for seperating values 
    headerlinesIn = 1;   %which line is header

    [A] = importdata (filename);

    I = A.data (:,:);
    X1 = II(:,1);  %define X1
    Y1 = II(:,2);  % define Y1

    X2 = II(:,3);  %define X2
    Y2 = II(:,4);  %define Y2

 %loop for reading data from txt file and return the index value 

       for k = 1: numel (Imfiles(1:2))
            fileNames = Imfiles(k).name;
            imIndexed = imread (fileNames);
            Z1 = impixel (imIndexed(:,:,3), X1(k),Y1(k));
            Z1(k,:) =(Z1(:,:,1))         
            Z2 = impixel (imIndexed(:,:,3), X2(k),Y2(k)); 
            Z2(k,:) =(Z2(:,:,1))         
        end

return matlab中索引图像的索引值

return index value from index image in matlab

matlab

pixel

image-processing