Forward interpolation approach using forward and backward mapping

An apparatus, comprising:

• one or more processors;
• and
• a storage containing instructions which, when executed by the one or more processors, cause the one or more processors to perform operations comprising:
• performing a forward mapping operation to map a specific input pixel to an output pixel, wherein the specific input pixel is one of a plurality of pixels in a first version of an image, and wherein the output pixel is one of a plurality of pixels in a second version of the image;
• selecting, based at least partially upon the output pixel to which the specific input pixel has been mapped, a set of candidate pixels, which includes one or more pixels in the second version of the image that are within proximity of the output pixel, wherein the set of candidate pixels represents one or more pixels in the second version of the image that are potentially affected by the specific input pixel;
• for each candidate pixel in the set of candidate pixels:
• performing a backward mapping operation to map the candidate pixel to a corresponding pixel in the first version of the image;
• and
• determining whether the corresponding pixel is the specific input pixel, wherein each candidate pixel that maps back to the specific input pixel is deemed an affected pixel;
• and
• deriving a pixel value for each affected pixel.

A method performed by an image processing device, comprising:

• performing a forward mapping operation to map a specific input pixel to an output pixel, wherein the specific input pixel is one of a plurality of pixels in a first version of an image, and wherein the output pixel is one of a plurality of pixels in a second version of the image;
• selecting, based at least partially upon the output pixel to which the specific input pixel has been mapped, a set of candidate pixels, which includes one or more pixels in the second version of the image that are within proximity of the output pixel, wherein the set of candidate pixels represents one or more pixels in the second version of the image that are potentially affected by the specific input pixel;
• for each candidate pixel in the set of candidate pixels:
• performing a backward mapping operation to map the candidate pixel to a corresponding pixel in the first version of the image;
• and
• determining whether the corresponding pixel is the specific input pixel, wherein each candidate pixel that maps back to the specific input pixel is deemed an affected pixel;
• and
• deriving a pixel value for each affected pixel.