Question

in Matlab,

if I do:

output = false(5, 5);
imshow(output);

it will show me a black square instead of a white binary square image. Is there any reason to this? How can I output a white binary square?

Answer 1

The reason is that false is mapped to 0, and true is mapped to 1.
Also, when showing images, higher number is shown by higher intensity. White has more intensity than black.

Another way to think about it, is that usually you have 256 values – 0-255. 0 is totally black and 255 is totally white. Now, imagine that you do a quantization to two colors. It is now obvious that 0 should be black.

In order to show white square, use

  output = true(5,5)