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US 7,804,525 B2Granted
Method, apparatus, and system for selecting pixels for automatic white balance processing
AssigneeMicron Technology, Inc.
InventorIgor Subbotin
Life of this patent
Estimating the term…
Abstract
A method, apparatus, and system that use a white balance operation. A selecting process is applied to each pixel selected and considered for automatic white balance statistics to determine the distance from the selected pixel to a white curve defined in a white area corresponding to an image sensor.
Claims8
An imaging device, comprising:
- a pixel array for capturing an image;
- and
- an image processing circuit for performing a white balancing operation;
- the image processing circuit comprising:
- a first circuit portion for:
- calculating first respective distances between a node from a selected pixel from the captured image and each node on a white curve defining a predetermined white area of the image sensor, where the nodes are plotted in a two-dimension space;
- selecting two of the white curve nodes closest to the selected pixel node;
- dividing an interval between the two closest white curve nodes into multiple intervals having a set of sub-nodes;
- calculating second respective distances between the selected pixel node and each sub-node;
- selecting a distance determined to be shortest distance among the second respective distances;
- and
- saving pixel data for a selected pixel if said selected distance is less than a predetermined value;
- and
- a second circuit portion for performing an automatic white balance operation using the saved pixel data.
11 more elements
An imaging system, comprising:
- a processor;
- and
- an imaging device coupled to the processor, the imaging device comprising:
- an image sensor for receiving an image and outputting an image signal that includes pixel data for each pixel of the image;
- and
- an image processor in communication with the image sensor for performing a white balancing operation on the image, the image processor comprising:
- means for defining a white curve as a piece-wise linear curve in a two-dimension space, wherein the white curve is located in the white area, and the piece-wise linear curve is defined by a set of white curve nodes;
- means for defining the pixel by a pixel node in the two-dimension space;
- means for calculating first respective distances between the selected pixel node and each white curve node;
- means for selecting two white curve nodes determined to be closest to the selected pixel node;
- means for defining an interval between the selected two white curve nodes by multiple sub-nodes;
- means for calculating second respective distances between the selected pixel node and each sub-node;
- means for selecting a shortest distance among the second respective distances;
- means for determining if the shortest distance is less than a predefined threshold distance;
- means for saving only pixels having a shortest distance which is less than the predefined distance to obtain automatic white balance statistics;
- and
- means for performing white balance on the image by applying the obtained automatic white balance statistics.
14 more elements
A camera, comprising:
- a lens;
- an image sensor for receiving an image from the lens and outputting an image signal that includes pixel data for each pixel of the image;
- a memory for storing a white curve associated with said image sensor, the white curves being defined by multiple node coordinates in a coordinate color space;
- and
- an image processor for processing the image signal, the image processor being operable on each of at least some pixels of the image, to:
- select the pixel from the image, the pixel having a pixel node in the color space;
- obtain coordinates for the stored white curve;
- calculate first respective distances from the selected pixel node to each white curve node;
- select two of the white curve nodes determined to be closest to the selected pixel node;
- divide an interval between the two white curve nodes into four equal sub-intervals, the sub-intervals being defined in the color space by sub-nodes;
- define the sub-intervals by a set of sub-nodes;
- calculate second respective distances from the selected pixel node to each sub-node;
- and
- save a pixel which has a shortest distance among the second respective distances, which is less than a threshold defining a boundary of a white area in the color space.
11 more elements
Dependencies are inferred from the claim text.