Source: http://www.google.com/patents/US7868928?dq=6272333
Timestamp: 2017-02-28 02:07:25
Document Index: 202886140

Matched Legal Cases: ['Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60']

Patent US7868928 - Low noise color correction matrix function in digital image capture systems ... - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inPatentsAn image processing system includes a filtering arrangement configured to receive incoming pixel information and filter at least a first portion of the information to thereby pass a second portion of the information for further processing; circuitry configured to apply a first color correction function...http://www.google.com/patents/US7868928?utm_source=gb-gplus-sharePatent US7868928 - Low noise color correction matrix function in digital image capture systems and methodsAdvanced Patent SearchTry the new Google Patents, with machine-classified Google Scholar results, and Japanese and South Korean patents.Publication numberUS7868928 B2Publication typeGrantApplication numberUS 11/686,632Publication dateJan 11, 2011Filing dateMar 15, 2007Priority dateMar 15, 2006Fee statusPaidAlso published asUS20070263264Publication number11686632, 686632, US 7868928 B2, US 7868928B2, US-B2-7868928, US7868928 B2, US7868928B2InventorsEugene FainstainOriginal AssigneeSamsung Electronics Co., Ltd.Export CitationBiBTeX, EndNote, RefManPatent Citations (45), Non-Patent Citations (6), Classifications (8), Legal Events (3) External Links: USPTO, USPTO Assignment, EspacenetLow noise color correction matrix function in digital image capture systems and methods
US 7868928 B2Abstract
An image processing system includes a filtering arrangement configured to receive incoming pixel information and filter at least a first portion of the information to thereby pass a second portion of the information for further processing; circuitry configured to apply a first color correction function to the incoming pixel information to thereby produce a modified first portion; circuitry configured to apply a second color correction function to the second portion to thereby produce a modified second portion; and an adder configured to combine the modified first portion to the modified second portion.
This application is a non-provisional of, and claims the benefit of, commonly assigned, U.S. Provisional Application No. 60/782,502, filed on Mar. 15, 2006, entitled “LOW NOISE COLOR CORRECTION MATRIX FUNCTION,” the entirety of which is herein incorporated by reference for all purposes.
This application is related to the following co-pending, commonly-assigned U.S. patent applications, the entirety of each of which being herein incorporated by reference for all purposes: U.S. patent application Ser. No. 10/474,798, filed Oct. 8, 2003, entitled “CMOS IMAGER FOR CELLULAR APPLICATIONS AND METHODS OF USING SUCH”; U.S. patent application Ser. No. 10/474,275, filed Feb. 11, 2005, entitled “CMOS IMAGER FOR CELLULAR APPLICATIONS AND METHODS OF USING SUCH”; U.S. patent application Ser. No. 10/474,799, filed Oct. 8, 2003, entitled “BUILT-IN SELF TEST FOR A CMOS IMAGER”; U.S. patent application Ser. No. 10/333,942, filed Apr. 29, 2003, entitled “SINGLE CHIP CMOS IMAGE SENSOR SYSTEM WITH VIDEO COMPRESSION”; U.S. patent application Ser. No. 11/101,195, filed Apr. 6, 2005, entitled “METHODS AND SYSTEMS FOR ANTI SHADING CORRECTION IN IMAGE SENSORS”; U.S. patent application Ser. No. 11/107,387, filed Apr. 14, 2005, entitled “SYSTEMS AND METHODS FOR CORRECTING GREEN DISPARITY IN IMAGER SENSORS”; U.S. patent application Ser. No. 11/223,758, filed Sep. 9, 2005, entitled “IMAGE FLICKER COMPENSATION SYSTEM AND METHOD,” which is a non-provisional, and claims the benefit, of U.S. Provisional Application No. 60/609,195, filed Sep. 9, 2004, entitled “IMAGER FLICKER COMPENSATION”; U.S. patent application Ser. No. 11/467,044, filed Aug. 24, 2006, entitled “SMEAR CORRECTION IN A DIGITAL CAMERA,” which is a non-provisional, and claims the benefit, of U.S. Provisional Application No. 60/711,156, filed Aug. 24, 2005, entitled “METHODS AND APPARATUS FOR SMEAR CORRECTION IN A DIGITAL CAMERA; U.S. patent application Ser. No. 11/467,044, filed Aug. 24, 2006, entitled “SMEAR CORRECTION IN A DIGITAL CAMERA,” which is a non-provisional, and claims the benefit, of U.S. Provisional Application No. 60/711,156, filed Aug. 24, 2005, entitled “METHODS AND APPARATUS FOR SMEAR CORRECTION IN A DIGITAL CAMERA; U.S. patent application Ser. No. 11/674,719, filed Feb. 14, 2007, entitled “POST CAPTURE IMAGE QUALITY ASSESSMENT,” which is a non-provisional, and claims the benefit, of U.S. Provisional Application No. 60/773,400, filed on Feb. 14, 2006, entitled “POST CAPTURE IMAGE QUALITY ASSESSMENT; and U.S. patent application Ser. No. 11/683,084, filed Mar. 7, 2007, entitled “LOW NOISE GAMMA FUNCTION IN DIGITAL IMAGE CAPTURE SYSTEMS AND METHODS,” which is a non-provisional, and claims the benefit, of U.S. Provisional Application No. 60/780,130, filed on Mar. 7, 2006, entitled “LOW NOISE GAMMA FUNCTION.”
Embodiments of the present invention relate generally to image capture. More specifically, embodiments of the invention relate to systems, circuits, and methods for low noise image signal processing.
Color correction is usually applied to captured images to correct the color by multiplying a 3×3 coefficient matrix by the R,G,B vector component of pixels received from an image sensor. Mathematically:
R ′ G ′ B ′ = [ C 1 , 1 C 1 , 2 C 1 , 3 C 2 , 1 C 2 , 2 C 2 , 3 C 3 , 1 C 3 , 2 C 3 , 3 ] · [ R G B ] Such color correction is done for the purpose of correcting for physical phenomena, for example, non-ideal color separation by the image sensor. In general, the sum of Ci,j elements in each row is 1, but the values of the elements Ci,j often include negative and positive numbers having an absolute value greater than 1. Simple mathematical analysis will show that error in the elements that are larger in absolute value than 1 result in error amplification at the output. The result is that the application the color correction matrix increases noise in the image.
Embodiments of the present invention provide an image processing system. The system includes a filtering arrangement configured to receive incoming pixel information and filter at least a first portion of the information to thereby pass a second portion of the information for further processing. The system also includes circuitry configured to apply a first color correction function to the incoming pixel information to thereby produce a modified first portion and circuitry configured to apply a second color correction function to the second portion to thereby produce a modified second portion. The system further includes an adder configured to combine the modified first portion to the modified second portion. In some embodiments, the system also includes delay circuitry configured to introduce a processing delay to thereby delay processing of the first portion prior to combining the modified first portion to the modified second portion. The filtering arrangement may be a spatial low-pass filter. The spatial low pass filter may include a multiplication matrix function. The multiplication matrix function may be applied to a 3×3 pixel region. The spatial low pass filter may be an infinite impulse response filter. The image processing system may be a digital still camera, a camera phone, a movie camera, or the like. The first color correction function may include a unity matrix and may be applied to luminance information. The second color correction function may be a zero mean matrix and may be applied to chrominance information.
Embodiments of the present invention relate to capturing images. In order to provide a context for describing embodiments of the present invention, embodiments of the invention will be described herein with reference to digital image capture. Those skilled in the art will appreciate, however, that other embodiments are possible. The ensuing description provides preferred exemplary embodiment(s) only, and is not intended to limit the scope, applicability or configuration of the invention. Rather, the ensuing description of the preferred exemplary embodiment(s) will provide those skilled in the art with an enabling description for implementing a preferred exemplary embodiment of the invention. It is to be understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the invention as set forth in the appended claims.
C = [ C 1 , 1 C 1 , 2 C 1 , 3 C 2 , 1 C 2 , 2 C 2 , 3 C 3 , 1 C 3 , 2 C 3 , 3 ] is replaced with C 1 = [ 1 0 0 0 1 0 0 0 1 ] and C 2 = [ C 1 , 1 - 1 C 1 , 2 C 1 , 3 C 2 , 1 C 2 , 2 - 1 C 2 , 3 C 3 , 1 C 3 , 2 C 3 , 3 - 1 ] , such that C1+C2=C. Note that other matrices are possible.
Input pixel information enters the circuit at 110 and is applied to a spatial low-pass filter 120. In some embodiments the spatial low pass filter 120 is a multiplication of the 3×3 pixels around a current pixel by elements of a constant 3×3 matrix. An exemplary low pass filter matrix is depicted in FIG. 2. In other embodiments, different matrices may be used, with different sizes of the environment. In yet other embodiments, an infinite impulse response (IIR) filter may be used.
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