Multiple exposure high dynamic range image capture

A method for clustering pixels into patches, comprising:

• applying a morphological dilation operation on a binary image of relevant pixels, with a structuring element;
• applying a morphological close operation on the binary image, with another structuring element;
• applying a binary labeling algorithm to distinguish different patches;
• describing each patch by a bounding polygon;
• and
• outputting the patch description.

A method for selecting a replacement image from a plurality of candidate replacement images as a source for replacement patch image data, comprising:

• computing a weighted histogram of luma values of border area pixels of a particular patch of a reference image;
• dividing the histogram into a plurality of regions according to threshold values determined from relative exposure values of the candidate replacement images;
• calculating a score function for each histogram region;
• selecting the region with the maximum score;
• and
• outputting the corresponding candidate replacement image.

A method for replacing patch image data in a composite image, comprising:

• smoothing a patch image bounding polygon;
• upscaling the smoothed patch images to full image resolution;
• and
• blending the composite image and the upscaled smoothed patch image to produce an output image.

A system for detecting local motion between a reference image and a plurality of comparison images, comprising:

• a processor that:
• defines a number of luma thresholds that determine a group of reference image luma value ranges in which a particular comparison image is selected, the number corresponding to the number of comparison images;
• defines a difference threshold function that sets threshold values according to luma values of the reference image;
• for each particular comparison image, produces an intermediate detection map denoting local motion between the reference image and the particular comparison image by applying the threshold values on a difference image formed by comparing the reference image and the particular comparison image;
• and
• outputs a final detection map that is a union of the intermediate detection maps.

A system for clustering pixels into patches, comprising:

• a processor that:
• applies a morphological dilation operation on a binary image of relevant pixels, with a structuring element;
• applies a morphological close operation on the binary image, with another structuring element;
• applies a binary labeling algorithm to distinguish different patches;
• describes each patch by a bounding polygon;
• and
• outputs the patch description.

A system for selecting a replacement image from a plurality of candidate replacement images as a source for replacement patch image data, comprising:

• a processor that:
• computes a weighted histogram of luma values of border area pixels of a particular patch of a reference image;
• divides the histogram into a plurality of regions according to threshold values determined from relative exposure values of the candidate replacement images;
• calculates a score function for each histogram region;
• selects the region with the maximum score;
• and
• outputs the corresponding candidate replacement image.

A system for replacing patch image data in a composite image, comprising:

• a processor that:
• smooths a patch image bounding polygon;
• upscales the smoothed patch images to full image resolution;
• and
• blends the composite image and the upscaled smoothed patch image to produce an output image.

A system for converting images from an initial format to a lower bits-per-pixel format, comprising:

• a processor that:
• performs a tone mapping that adapts to image luma values;
• and
• outputs the tone mapped image.

A method for creating a high dynamic range composite image from multiple exposures, comprising:

• detecting local motion between a reference image and a plurality of comparison images;
• clustering relevant pixels into patches;
• selecting a replacement image from a plurality of candidate replacement images as a source for replacement patch image data;
• replacing patch image data in a composite image;
• and
• converting images from an initial format to a lower bits-per-pixel format for display.

A system for creating a high dynamic range composite image from multiple exposures, comprising:

• a processor configured for:
• detecting local motion between a reference image and a plurality of comparison images;
• clustering relevant pixels into patches;
• selecting a replacement image from a plurality of candidate replacement images as a source for replacement patch image data;
• replacing patch image data in a composite image;
• and
• converting images from an initial format to a lower bits-per-pixel format for display.

A computer program product for creating a high dynamic range composite image from multiple exposures, comprising a machine-readable medium tangibly embodying thereon non-transitory program instructions that when executed by a computer system cause the computer system to:

• detect local motion between a reference image and a plurality of comparison images;
• cluster relevant pixels into patches;
• select a replacement image from a plurality of candidate replacement images as a source for replacement patch image data;
• replace patch image data in a composite image;
• and
• convert images from an initial format to a lower bits-per-pixel format for display.