Color correction circuit and image display apparatus using same

• US 8,594,421 B2
• Filed: 09/05/2008
• Issued: 11/26/2013
• Est. Priority Date: 09/06/2007
• Status: Expired due to Fees

• Current Assignee: ATRC Corporation, Mitsumi Electric Co., Ltd. (Minebea Mitsumi, Inc.)
• Original Assignee: ATRC Corporation, Mitsumi Electric Co., Ltd. (Minebea Mitsumi, Inc.)
• Inventors: Adachi, Takeshi
• Primary Examiner(s): Liu, Li
• Application Number:
  US12/675,330
• Publication Number:
  US 20100226572A1
• Time in Patent Office: 1,908 Days
• Field of Search: None
• US Class Current: 382/167
• CPC Class Codes: G06T 11/001 Texturing; Colouring; Generation of texture or colour inpainting G06T5/77
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• CPC Class Codes: G09G 2340/06 Colour space transformation
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 5/06 using colour palettes, e.g. look-up tables
• CPC Class Codes: H04N 1/6075 Corrections to the hue
• CPC Class Codes: H04N 1/62 Retouching, i.e. modification of isolated colours only or in isolated picture areas only
• CPC Class Codes: H04N 9/643 Hue control means, e.g. flesh tone control
• CPC Class Codes: H04N 9/77 Circuits for processing the brightness signal and the chrominance signal relative to each other, e.g. adjusting the phase of the brightness signal relative to the colour signal, correcting differential gain or differential phase circuits for matrixing H04N9/67

Abstract

A color correction circuit includes a detection part configured to detect the luminance information and chromaticity histogram information of an input video signal of one of an RGB color space and a YCbCr color space, the chromaticity histogram information including chroma and hue information; and a control part configured to control the color reproduction of the video signal based on the luminance information and the chromaticity histogram information detected by the detection part. The detection part includes a hue detection part configured to convert the video signal to an HSV color space and to detect a hue of the video signal from hues of the HSV color space.

Claims

1. A color correction circuit, comprising:

a luminance information detection circuit configured to detect luminance information that includes a luminance histogram and average luminance information in one or more field periods or in one or more frames of an input video signal;

a chromaticity histogram information detection circuit configured to detect chromaticity histogram information that includes a chromaticity histogram including a hue histogram and a chroma histogram of the video signal;

a hue detection part configured to convert an RGB signal to an HSV color space and to detect a hue of the video signal from hues of the HSV color space,

wherein the RGB signal is input as the video signal or obtained by converting a YCbCr signal input as the video signal;

a memory configured to store matrix coefficients used for a color correction matrix operation as a look-up table;

a memory control part configured to determine a color of the video signal to be corrected based on the luminance histogram and the average luminance information detected in the luminance information detection circuit, the hue histogram and the chroma histogram detected in the chromaticity histogram information detection circuit, and the hue detected in the hue detection part; and

a color correction matrix operation part configured to correct a hue of the color of the video signal determined to be corrected by the color correction matrix operation using the matrix coefficients and the RGB signal before being converted to the HSV color space.

2. The color correction circuit as claimed in claim 1, wherein:

the color correction matrix operation part is configured to correct the hue of the color of the video signal in accordance with a status of the average luminance information, the luminance histogram, and the chromaticity histogram.

3. The color correction circuit as claimed in claim 1, wherein the matrix coefficients are coefficients correcting necessary hues in accordance with a color characteristic of a display device configured to display the video signal.

4. An image display apparatus, comprising:

the color correction circuit as set forth in claim 1; and

a display device configured to display a video signal corrected by the color correction circuit.