Since your areaArr is 9 pixels, not 8, you'll need to extract just the 8 neighbors, not a 3x3 square.
areaArr = isColor(row-1:row+1, col-1:col+1);
areaArr = areaArr(:); % Turn into column vector.
areaArr(5) = []; % Delete middle one.
To determine if the pixels is on the edge, check if the row or column is at the limits
[rows, columns, numColorChannels] = size(myImg)
if row == 1
% It's on the left edge
end
if row == rows
% It's on the right edge
end
if col == 1
% It's on the top edge
end
if col == columns
% It's on the bottom edge
end
That's basically it, however you'll also have to check if the pixel is exactly in one of the 4 corners. That's just adding 4 additional if blocks, which I assume you can figure out.
