Creating a Vector from Average Image Values

I'm trying to create a vector of the averages of a 3x3 kernel for each layer of an image. I have the following code where I have initialized red/green/blueAvg as 0, and red/green/blue as an empty vector [ ]. I have checked the debugger and the vector values seem to be the right size, at 1x296, after only the for y = ... loop is run but once the for x = ... loop is exited, the vector value increases to 1x48544....Any ideas? (For more info: red/green/blueDoub are equal to double values at that layer (instead of uint8))

for x = 2:row-1
    for y = 2:col-1
            redAvg = mean(mean(redDoub(x - 1: x +1, y - 1: y + 1)));

              greenAvg =  mean(mean(greenDoub(x - 1: x +1, y - 1: y + 1)));

              blueAvg =  mean(mean(blueDoub(x - 1: x +1, y - 1: y + 1)));

              red = [red redAvg];
              green = [green greenAvg];
              blue = [blue blueAvg];
      end
  end

Answer 1

[Walter Roberson]

That sounds about right. 48544 is 296 * 164, so you are probably working with a 298 x 166 matrix and appending one entry for each interior member of the matrix. This is what you say you want to do, since you asked to create a vector for each layer of an image.

Have you considered simplifying your code?

redavg = conv2(redDoub, ones(3,3)/9, 'same');
greenavg = conv2(greenDoub, ones(3,3)/9, 'same');
blueavg = conv2(blueDoub, ones(3,3)/9, 'same');

red = reshape( redavg(2:end-1, 2:end-1), 1, []);
blue = reshape( blueavg(2:end-1, 2:end-1), 1, []);
green = reshape( greenavg(2:end-1, 2:end-1), 1, []);