COLOR SIGNAL PROCESSING DEVICE

• US 20130222414A1
• Filed: 04/12/2013
• Published: 08/29/2013
• Est. Priority Date: 10/12/2010
• Status: Active Grant

• Current Assignee: Godo Kaisha IP Bridge 1 (IP Bridge, Inc.)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: ITO, Takeshi, YAMASHITA, Haruo, HIRASHIMA, Tsuyoshi
• Granted Patent: US 9,430,986 B2
• Time in Patent Office: Days
• US Class Current: 345/600
• CPC Class Codes: G09G 2340/06 Colour space transformation
• CPC Class Codes: G09G 3/3607 for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels display of colours in flat matrix panels other than liquid crystal displays G09G3/2003; grey scales specific for television H04N3/127
• CPC Class Codes: G09G 5/02 characterised by the way in which colour is displayed details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607

Abstract

A color signal processing device for generating image data to be displayed on a display device which represents a color by using at least four primary colors, includes an obtainer that obtains a color signal regarding three primary colors for image data composed of a plurality of pixels, a changer that changes a value of the obtained color signal regarding the three primary colors, and a converter that converts the changed color signal regarding the three primary colors into a color signal regarding four primary colors. When a predetermined region contains a color saturated pixel, the changer makes the value of the color signal of at least one color of the three primary colors smaller, for pixels contained in the predetermined region.

Claims

1. A color signal processing device for generating image data to be displayed on a display device which represents a color by using at least four primary colors, comprising:

an obtainer that obtains a color signal regarding three primary colors for image data composed of a plurality of pixels;

a changer that changes a value of the obtained color signal regarding the three primary colors; and

a converter that converts the changed color signal regarding the three primary colors into a color signal regarding four primary colors, wherein

when a predetermined region contains a color saturated pixel, the changer makes the value of the color signal of at least one color of the three primary colors smaller, for pixels contained in the predetermined region, and

the color saturated pixel is a pixel, of which a color indicated by the color signal converted by the converter is a color outside of a displayable color gamut of the display device.

3. The color signal processing device according to claim 1, wherein

when number of pixels of which color signal converted by the converter is a signal indicating color outside of the displayable color gamut is larger than a first threshold value, the changer decreases the value of the color signal for the pixels contained in the predetermined region.

4. The color signal processing device according to claim 3, wherein

when the number of pixels of which color signal converted by the converter is the signal indicating color outside the displayable color gamut of the display device is smaller than a second threshold value which is smaller than the first threshold value, the changer increases the value of the color signal for the pixels contained in the predetermined region.

5. The color signal processing device according to claim 1, wherein

when the changer changes the value of the color signal, the changer changes the value at a predetermined rate.

6. The color signal processing device according to claim 5, wherein

when the changer increases the value of the color signal, the changer increases the value at a first rate, and

when the changer decreases the value of the color signal, the changer decreases the value at a second rate which is different from the first rate.

7. The color signal processing device according to claim 1, further comprising a generator that generates a control signal regarding the amount of emission of a backlight in the display device from the obtained color signal for the plurality of pixels, wherein

when the changer decreases the value of the color signal, the generator controls the control signal to increase the amount of emission of the backlight.

8. The color signal processing device according to claim 1, wherein

the changer changes the value of the color signal based on the hue of the color indicated by the color signal.

9. The color signal processing device according to claim 8, wherein

the changer increases the rate of decreasing the color signal for the pixel of which color signal having a yellow hue, higher than the rate of decreasing the color signals for the pixel having other color hues.

10. The color signal processing device according to claim 1, further comprising:

a block divider that divides the entire region of the image into a plurality of blocks; and

a detector that detects whether there is a pixel of which color signal converted by the converter is a signal indicating a color outside of the displayable color gamut of the display device in each block, wherein

the changer changes the value of the color signal based on the detection result of the detector for each block.

11. The color signal processing device according to claim 10, wherein

the changer calculates a gain value based on the detection result of the detector and changes the value of the color signal based on the calculated gain value for each block.

12. The color signal processing device according to claim 11, wherein

the changer performs smoothing processing for smoothing the gain values calculated for the respective blocks among the blocks, wherein

the smoothing processing smooths the gain values so that, out of blocks around a target block of the smoothing processing, a block having the brightness smaller than that of the target block influences stronger than a block having the brightness larger than the brightness of the target block.

2. A color signal processing device for generating image data to be displayed on a display device which represents a color by using at least four primary colors, comprising:

an obtainer that obtains a color signal regarding three primary colors for image data composed of a plurality of pixels;

a changer that changes a value of the obtained color signal regarding the three primary colors; and

a converter that converts the obtained color signal regarding the three primary colors into a color signal regarding four primary colors based on a predetermined conversion characteristic, wherein

the changer makes the value of the color signal of at least one primary color of the three primary colors smaller, for pixel contained in a predetermined region based on the conversion characteristic of the converter to prevent a color indicated by the converted color signal from being a color outside of a displayable color gamut of the display device in the predetermined region.