Rendering algorithms: Viewing screen superposition

Rendering algorithms: Viewing screen superposition

Once mapping of viewing screen and scan coordinates is made, it is possible to simulate the superposition of viewing screen and transparency. This means that for every pixel of the input image the color of viewing screen is determined in RGB values that represents intensities of each color dye and these RGB values are multiplied by the luminosity of the pixel.

Since scans nor viewing screens are perfectly sharp, parameter screen_blur_radius determine how much the simulated ideal screen should be blurred for this process.

Future plans

For later algorithms it is very desirable to make screen blurring to match the blur caused by the combination of photographic emulsion and scanner, so it precisely match the blur of original viewing screen. Instead of simple screen_blur_radius we may implement bluring based on fourier transformation that takes an MTF curve of the system as parameter.