Patent attributes
To allow the needed versatile image or video combination now that HDR videos of considerably different luminance characteristics are appearing, the apparatus (301) for combining two images or two videos of images (Im_HDR, Im_LDR), one of them being a high dynamic range image or video, the apparatus comprising: —a dynamic range establishing unit (302) arranged to establish a combination luminance dynamic range (CombRng), being characterized by at least a maximum luminance (LMC) which is determined based on at least one of: a maximum luminance of at least one of the two images or the two videos of images, and a peak brightness of a display for rendering the two images or the two videos of images, the dynamic range establishing unit further comprising a luminance anchor determining unit (303), arranged to determine an anchor luminance (anc) in the combination luminance dynamic range (CombRng), —a color transformation unit (310), arranged to perform at least a luminance transformation on at least one of the two images or videos, wherein the color transformation unit (310) comprises a source anchor luminance reading unit (311) arranged to read at least one source anchor luminance (L_SA1) from a first source (350) which delivers a first image or video (Im1_LDR) of the two images or videos, and wherein the color transformation unit is arranged to establish a color transformation (FF_1) to be applied to the first image or video, which color transformation is dependent on the value of the source anchor luminance (L_SA1) by having the property that the source anchor luminance (L_SA1) is mapped to an output luminance in a vicinity of the anchor luminance (anc); and —an image combination unit (320) arranged to combine the two images or two videos of images to form at least one output image (Im_o).
