Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for color-space selective darkness and lightness improvements. In one aspect, a method accessing multiple pixels that represent a digital image in an RGB color space. The accessed pixels are processed based on a darkness of the digital image resulting in a first set of processed pixels, and separately based on a lightness of the digital image resulting in a second set of processed pixels. Both sets of processed pixels are combined to generate a processed output image.

Abstract: Some embodiments provide a method of operating a device to capture an image of a high dynamic range (HDR) scene. Upon the device entering an HDR mode, the method captures and stores multiple images at a first image exposure level. Upon receiving a command to capture the HDR scene, the method captures a first image at a second image exposure level. The method selects a second image from the captured plurality of images. The method composites the first and second images to produce a composite image that captures the HDR scene. In some embodiments, the method captures multiple images at multiple different exposure levels.

Abstract: Some embodiments of the invention provide a mobile device that captures and produces images with high dynamic ranges. To capture and produce a high dynamic range image, the mobile device of some embodiments includes novel image capture and processing modules. In some embodiments, the mobile device produces a high dynamic range (HDR) image by (1) having its image capture module rapidly capture a succession of images at different image exposure durations, and (2) having its image processing module composite these images to produce the HDR image.

Abstract: Some embodiments provide a method of aligning a pair of images. The method defines multiple different pairs of images at multiple different resolutions. The method hierarchically aligns the original pair of images by first aligning the pair of images at the lowest resolution and then aligning each pair of images at each higher resolution based on the alignments of the pair of images at the lower resolutions. For some of the resolutions, to perform the hierarchically alignment, the method identifies, for at least one image at each resolution, portions that are suitable for performing the alignment and portions that are not suitable for performing the alignment. The method compares each pair of images at a particular resolution by using the suitable portions while excluding the unsuitable portions from the comparison.