greyscale

Implementation of different conversion algorithms using OpenCV.

Spread

For each pixel, it selects one of the RGB components and assigns it to the other two components of the pixel.

Average

Calculates the average of the three color components and assigns it to all subpixels.

Lightness method

Calculates the average between the maximum and minimum color components and assigns it to all subpixels.

Weighted sum (luminance preserving)

All subpixels get the value obtained by: 0.2126R + 0.7152G + 0.0722B