| 摘要 |
Methods, devices and computer readable instructions to generate multi-scale tone curves are disclosed. One method includes finding, for a given input image, a global tone curve that exhibits monotonic behavior. The input image may then be partitioned into a first number of sub-regions. For each sub-region, a local tone curve may be determined that has an output level that is constrained to the global tone curve at one or more first luminance levels so that each sub-region's local tone curve's output follows the global tone curve's monotonic behavior. If the resulting local tone curves provide sufficient control of shadow-boost, highlight-suppression, and contrast optimization the first number of local tone curves may be applied directly to the input image. If additional control is needed, each sub-region may again be partitioned and local tone curves determined for each of the new sub-regions. |
| 主权项 |
1. A non-transitory program storage device comprising instructions stored thereon to cause one or more processors to:
obtain an input image characterized by a single region; find a global tone curve of the input image that exhibits monotonic behavior; partition the input image's single region into a first plurality of first sub-regions; determine, for each first sub-region, a first local tone curve that yields an output that is constrained to the global tone curve at a first one or more luminance levels; repeat the partition and determine instructions zero or more times, wherein each time the partition instructions are performed each sub-region resulting from an immediately prior partition (a prior sub-region) is further partitioned into a next plurality of next sub-regions, wherein each next plurality of next sub-regions has a corresponding prior sub-region that has a prior local tone curve, and wherein each time the determine instructions are performed a next local tone curve is determined for each of the next plurality of next sub-regions, wherein the output of each next sub-region's next local tone curve is constrained to the next sub-region's corresponding prior sub-region's prior local tone curve at a next one or more luminance levels; apply each of the first local tone curves to the input image to generate an output image when the partition and determine instructions are repeated zero times; apply each of the next local tone curves from a last repeat of the partition and determine instructions to the input image to generate an output image when the partition and determine instructions are repeated one or more times; and store the output image in a memory. |
