Patent ID: 8743291

Claim:
A method, comprising the steps of: accessing a first video signal that is represented in a first color space with a first color gamut which is related to a first dynamic range, and a second video signal that is represented in a second color space of a second color gamut, wherein the second color space is associated with a second dynamic range; converting the accessed first video signal to a converted video signal that is represented in the second color space of the second color gamut with the second dynamic range; processing the converted video signal and the accessed second video signal, wherein for at least one frame of the converted video signal and a corresponding frame of the second video signal the processing step comprises: applying a non-linear scaling function to the converted video signal to generate a first scaled video signal; applying the non-linear scaling function to the second video signal to generate a second scaled video signal; and applying a photographic mapping function to the first scaled video signal and the second scaled video signal to generate a first mapped video signal and a second mapped video signal; and based at least in part on the processing step, measuring a difference between the processed first mapped and second mapped video signals, wherein measuring the difference comprises: generating based at least in part on the first mapped video signal and the second mapped video signal a luminance comparison metric, a contrast comparison metric, and a structural comparison metric; and combining the luminance comparison metric, the contrast comparison metric, and the structural comparison metric to generate a quality metric which indicates how pixels of the first video signal match corresponding pixels of the second video signal.