Local Tone Mapping for High Dynamic Range Images

The method of claim 6, wherein computing a pixel value further comprises:

• computing a motion adaptation weight for each pixel location of the long exposure image;
• computing a weight for each pixel location of the long exposure image based on the merging weight computed for the pixel location of the long exposure image and the motion adaptation weight computed for each pixel location of the long exposure image;
• and
• computing a weight for each pixel location of the short exposure image by subtracting the weight computed for the pixel location in the long exposure image from one.

An apparatus configured to perform local tone mapping of a high dynamic range (HDR) image, the apparatus comprising:

• means for generating the HDR image;
• means for generating a luminance image of the HDR image;
• means for dividing the luminance image into overlapping blocks and computing a local tone curve for each block;
• means for computing a tone mapped value for each pixel of the luminance image as a weighted sum of N values computed by applying local tone curves of N neighboring blocks of the pixel to a value of the pixel, wherein a weight for each value of the N values is computed based on distance from the pixel to a center point of the block having the local tone curve applied to compute the value of the N values and an intensity difference between the value of the pixel and a mean pixel value of the block, wherein N is an integer;
• means for computing a gain for each pixel of the luminance image as a ratio of the tone mapped value to the value of the pixel;
• and
• means for applying the computed gains to corresponding pixels in the HDR image to generate a tone-mapped HDR image.

The apparatus of claim 16, wherein computing a pixel value further comprises:

• computing a motion adaptation weight for each pixel location of the long exposure image;
• computing a weight for each pixel location of the long exposure image based on the merging weight computed for the pixel location of the long exposure image and the motion adaptation weight computed for each pixel location of the long exposure image;
• and
• computing a weight for each pixel location of the short exposure image by subtracting the weight computed for the pixel location in the long exposure image from one.