Method and apparatus of creating a perceptual harmony map
View Patent ↗The present invention generally relates to a method and apparatus for creating an harmony map of an image. It also relates to a method and apparatus for assessing the quality of an image. The invention also relates to a method and apparatus for assessing the quality of an image such that an assessment score of the image is obtained from a perceptual map of the image created from the previous method. As an interesting tool for content creator and in the goal of maximizing the artistic effect, the proposed method provides perceptual harmony-guided quality map as well as a score of disharmony of a picture without reference image. The method links two distinct subjects: perceptual quality metric and harmonious hue templates in order to provide new tools to content creator whatever the expertise level.
1. A method performed by a device for creating a perceptual harmony map of an image from at least one harmonious color template defined by a center and at least a sector wherein the method comprises:
calculating, by a processor, a multi-resolution decomposition of the image,
at each resolution level,
for each harmonious color template, computing, by said processor, an optimal rotation angle of said harmonious color template around its center and an harmony distance for the hue value associated with each pixel of the image at the resolution level, said harmony distance quantifying the distance between said hue value and a sector of said harmonious color template, and computing a harmony distance map by weighting the sum of harmony distances calculated for the harmonious color templates
calculating, by said processor, a contrast map and an entropy activity map reflecting the uncertainty of the image,
obtaining, by said processor, a perceptual harmony map by integrating together the contrast map the entropy activity map and the harmony distance map, and
obtaining, by said processor, the perceptual map by accumulating the perceptual harmony maps calculated over the different resolution levels.
2. The method of claim 1 , wherein an assessment score of the image is obtained, by said processor, from the perceptual map.
3. A processor readable non-transitory medium having stored therein instructions for causing a processor to perform at least the steps of the method according to claim 1 .
4. A processor readable non-transitory medium having stored therein instructions for causing a processor to perform at least the steps of the method according to claim 2 .
5. Non-transitory storage medium carrying instructions of program code for executing steps of the method according to claim 1 , when said program is executed on a computing device.
6. Device for creating a perceptual harmony map of an image from at least one harmonious color template defined by a center and at least a sector wherein it comprises a processor configured to:
calculate a multi-resolution decomposition of the image,
at each resolution level,
for each harmonious color template, compute an optimal rotation angle of said harmonious color template around its center and an harmony distance for the hue value associated with each pixel of the image at the resolution level, said harmony distance quantifying the distance between said hue value and a sector of said harmonious color template, and compute a harmony distance map by weighting the sum of harmony distances calculated for the harmonious color templates
calculate a contrast map and an entropy activity map reflecting the uncertainty of the image,
obtain a perceptual harmony map by integrating together the contrast map the entropy activity map and the harmony distance map, and
obtain the perceptual map by accumulating the perceptual harmony maps calculated over the different resolution levels.
7. A device for assessing the quality of an image, wherein it comprises a processor configured to obtain an assessment score of the image from a perceptual map of the image, the device wherein the processor is further configured to:
calculate a multi-resolution decomposition of the image,
at each resolution level,
for each harmonious color template, compute an optimal rotation angle of said harmonious color template around its center and an harmony distance for the hue value associated with each pixel of the image at the resolution level, said harmony distance quantifying the distance between said hue value and a sector of said harmonious color template, and compute a harmony distance map by weighting the sum of harmony distances calculated for the harmonious color templates
calculate a contrast map and an entropy activity map reflecting the uncertainty of the image,
obtain a perceptual harmony map by integrating together the contrast map the entropy activity map and the harmony distance map, and
obtain the perceptual map by accumulating the perceptual harmony maps calculated over the different resolution levels.