Method and apparatus for implementing moving image color appearance model for video quality ratings prediction
View Patent ↗Embodiments of the invention include systems and methods for predicting video quality through human vision perceptual color response and associated perceptual differences of video relative to a reference. Embodiments include a model of the human vision system developed as an extension to CIECAM02 to predict the macro-behavioral response to light stimuli with the following varying parameters, in addition to the parameters relevant to CIECAM02: spatial frequency, temporal frequency, angular extent, temporal extent, and surround.
1. A method of predicting color visual differences in video, comprising:
accepting a video signal to be analyzed;
receiving an unfiltered white signal corresponding to the video display and viewing environment;
creating a spatial surround from the video signal;
creating a spatial center from the video signal; and
creating a temporal surround of the video signal from a combination of the spatial surround, the spatial center, and the unfiltered white signal using one or more weighting factors.
2. The method of claim 1 , in which the unfiltered white signal is a combination of one or more of an ambient white signal, a display white signal, and an absolute white signal.
3. The method of claim 2 , further comprising:
combining the ambient white signal and the display white signal according to a first combinational weighting factor to create an intermediate white signal; and
creating the unfiltered white signal by combining the intermediate white signal and the absolute white signal according to a second combinational weighting factor.
4. The method of claim 1 in which creating a temporal surround comprises temporally filtering data through a variable rate filter.
5. The method of claim 1 in which creating a temporal surround comprises temporally filtering data through an adaptable filter.
6. The method of claim 1 in which creating a temporal surround comprises temporally filtering data through an asymmetric filter.
7. The method of claim 1 in which creating a temporal surround comprises temporally filtering data through a recursive filter.
8. The method of claim 6 , in which temporally processing the stream further comprises:
filtering data though a first and a second low pass filter.
9. The method of claim 8 , in which at least one of a set of operating parameters of the second low pass filter varies depending on a color movement direction.
10. The method of claim 8 , further comprising adding outputs of the first and second low pass filters to produce the temporal surround.
11. A system for moving image color appearance modeling, comprising:
an input structured to accept a video signal;
a white generator structured to create an unfiltered white signal from the video signal;
a cone response generator coupled to the input and structured to generate a set of cone responses from the video signal;
a spatial center filter structured to generate a spatial center of one of the set of cone responses;
a spatial surround filter structured to generate a spatial surround of the one of the set of cone responses; and
a temporal surround filter structured to generate a temporal surround from the spatial center, spatial surround, and the unfiltered white signal.
12. The system of claim 11 , further comprising:
a first mix controller structured to combine the unfiltered white signal with the spatial surround according to a first weighting factor.
13. The system of claim 12 , further comprising:
a second mix controller structured to combine an output from the first mix controller with the spatial center according to a second weighting factor.
14. The system of claim 11 , in which the unfiltered white signal comprises a combination of an ambient white signal, a display white signal, and an absolute white signal.
15. The system of claim 11 , in which the temporal surround filter further comprises a first low pass filter, a second low pass filter, and a comparator coupled to an input and an output of the second low pass filter.
16. The system of claim 11 , further comprising a set of spatial center filters, a set of spatial surround filters, and a set of temporal surround filters for each of the set of cone responses.
17. The system of claim 11 in which the temporal surround filter is a variable rate filter.
18. The system of claim 11 in which the temporal surround filter is an adaptable filter.
19. The system of claim 11 in which the temporal surround filter is an asymmetric filter.
20. The system of claim 11 in which the temporal surround filter is a recursive filter.