Package-level declarations

Focus score on a normalised copy whose longest side is normalizedSize, so results are comparable between a 4K photo and a 720p camera frame.

Focus measure: variance of the 4-neighbour Laplacian. Higher is sharper.

Mean luma in 0.0..255.0.

Fraction (0.0..1.0) of pixels where all channels are at least threshold - i.e. blown-out highlights such as glare on a laminated card.