IMAGE PROCESSING CIRCUIT FOR IMAGE COMPRESSION AND DECOMPRESSION AND DISPLAY PANEL DRIVER INCORPORATING THE SAME

• US 20140146098A1
• Filed: 10/25/2013
• Published: 05/29/2014
• Est. Priority Date: 11/28/2012
• Status: Active Grant

• Current Assignee: Synaptics Japan GK (Synaptics Incorporated)
• Original Assignee: Renesas SP Drivers Inc. (Synaptics Incorporated)
• Inventors: Nose, Takashi, Furihata, Hirobumi, Sugiyama, Akio
• Granted Patent: US 10,089,953 B2
• Time in Patent Office: Days
• US Class Current: 345/694
• CPC Class Codes: G09G 2310/027 Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
• CPC Class Codes: G09G 2340/02 Handling of images in compressed format, e.g. JPEG, MPEG
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 2360/18 Use of a frame buffer in a display terminal, inclusive of the display panel
• CPC Class Codes: G09G 3/2092 Details of a display terminals using a flat panel, the details relating to the control arrangement of the display terminal and to the interfaces thereto suitable for both CRT and flat panel G09G5/003; specific for a CRT G09G1/165
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: G09G 5/00 Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators image data processing or generation, in general G06T
• CPC Class Codes: H04N 19/12 Selection from among a plurality of transforms or standards, e.g. selection between discrete cosine transform [DCT] and sub-band transform or selection between H.263 and H.264
• CPC Class Codes: H04N 19/14 Coding unit complexity, e.g. amount of activity or edge presence estimation H04N19/146 takes precedence
• CPC Class Codes: H04N 19/17 the unit being an image region, e.g. an object
• CPC Class Codes: H04N 19/186 the unit being a colour or a chrominance component

Abstract

An image processing circuit includes: a representative-values calculation circuit and an all-combinations comparing compression circuit. The representative-values calculation circuit is configured to generate M datasets each including a plurality of representative values by performing a pre-process on image data associated with said N pixels, M being a natural number more than one and less than N. The all-combinations comparing compression circuit is configured to calculate correlations between two datasets selected from said M datasets for all possible combinations of the two datasets, to select a compression process from a plurality of compression processes in response to the calculated correlations, and to generate said compressed imaged data by compressing said M datasets by using said selected compression process. The image processing circuit may be incorporated in a display panel driver.

Claims

1. A display panel driver, comprising:

a compression circuit generating compressed image data by compressing image data associated with N pixels, N being an natural number equal to or more than three;

an image memory storing said compressed image data;

a decompression circuit generating decompressed image data by decompressing said compressed image data read from said image memory; and

a drive circuit driving a display panel in response to said decompressed image data,

wherein said compression circuit includes;

a representative-values calculation circuit configured to generate M datasets each including a plurality of representative values by performing a pre-process on said image data associated with said N pixels, M being a natural number more than one and less than N; and

an all-combinations comparing compression circuit configured to calculate correlations between two datasets selected from said M datasets for all possible combinations of the two datasets, to select a compression process from a plurality of compression processes in response to the calculated correlations, and to generate said compressed imaged data by compressing said M datasets by using said selected compression process.

2. The display panel driver, according to claim 1, wherein, in said pre-process, said representative-values calculation circuit performs grouping of said N pixels into M groups which are associated with said M datasets, respectively, and calculates the representative values included in each of said M datasets, based on image data of pixels belonging to associated one of said M groups.

3. The display panel driver, according to claim 2, wherein each of said N pixels includes a subpixel associated with a first color, a subpixel associated with a second color and a subpixel associated with a third color, and

wherein the grouping of said N pixels into said M groups is achieved by initially grouping said N pixels into a single group and repeatedly performing a procedure which involves:

selecting a group and color for which a difference between maximum and minimum values of grayscale levels of subpixels is largest from one or more groups of current interest, and grouping pixels belonging to the selected group into two groups depending on grayscale levels of subpixels associated with the selected color.

4. The display panel driver according to claim 1, wherein said M datasets includes four datasets,

wherein said plurality of compression processes include:

a first compression process which involves calculating a first representative value associated with said four datasets and incorporating said first representative value into said compressed image data;

a second compression process which involves calculating a second representative value associated with two of said four datasets, calculating a third representative value associated with the other two of said four datasets and incorporating said second and third representative values into said compressed image data;

a third compression process which involves calculating a fourth representative value associated with two datasets of said four datasets, generating first bit-reduced data by performing a bit-reducing process on each of the other two datasets independently, and incorporating said fourth representative value and said first bit-reduced data into said compressed image data; and

a fourth compression process which involves generating second bit-reduced data by performing a bit-reducing process on each of said four datasets, independently, and incorporating said second bit-reduced data into said compressed image data.

5. The display panel driver, according to claim 1, wherein said N pixels include eight pixels,

wherein said M datasets include four datasets each including three representative values, and

wherein, in said pre-process, said representative-values calculation circuit generates Y data, Cr data and Cb data for each of said eight pixels by performing a YCrCb transform on image data of said eight pixels, calculates eight first representative values from data selected from the Y data, Cr data and Cb data of said eight pixels, said selected data having a largest difference between maximum and minimum values, and calculates four second representative values from the remaining two of the Y data, Cr data and Cb data of said eight pixels, each of said four datasets including two of said eight first representative values and one of said four second representative values.

6. The display panel driver according to claim 5, wherein said plurality of compression processes include:

a first compression process which involves calculating a first representative value associated with said four datasets and incorporating said first representative value into said compressed image data;

a second compression process which involves calculating a second representative value associated with two of said four datasets, calculating a third representative value associated with the other two of said four datasets and incorporating said second and third representative values into said compressed image data;

a third compression process which involves calculating a fourth representative value associated with two datasets of said four datasets, generating a first bit-reduced data by performing a bit-reducing process on each of the other two datasets independently, and incorporating said fourth representative value and said first bit-reduced data into said compressed image data; and

a fourth compression process which involves generating second bit-reduced data by performing a bit-reducing process on each of said four datasets, independently, and incorporating said second bit-reduced data into said compressed image data.

7. A display device, comprising:

a display panel; and

a display panel driver driving said display panel,

wherein said display panel driver includes;

a compression circuit generating compressed image data by compressing image data associated with N pixels, N being an natural number equal to or more than three;

an image memory storing said compressed image data;

a decompression circuit generating decompressed image data by decompressing said compressed image data read from said image memory; and

a drive circuit driving a display panel in response to said decompressed image data,

wherein said compression circuit includes;

a representative-values calculation circuit configured to generate M datasets each including a plurality of representative values by performing a pre-process on said image data associated with said N pixels, M being a natural number more than one and less than N; and

an all-combinations comparing compression circuit configured to calculate correlations between two datasets selected from said M datasets for all possible combinations of the two datasets, to select a compression process from a plurality of compression processes in response to the calculated correlations, and to generate said compressed imaged data by compressing said M datasets by using said selected compression process.

8. The display device, according to claim 7, wherein, in said pre-process, said representative-values calculation circuit performs grouping of said N pixels into M groups which are associated with said M datasets, respectively, and calculates the representative values included in each of said M datasets, based on image data of pixels belonging to associated one of said M groups.

9. The display device, according to claim 8, wherein each of said N pixels includes a subpixel associated with a first color, a subpixel associated with a second color and a subpixel associated with a third color,

wherein the grouping of said N pixels into said M groups is achieved by initially grouping said N pixels into a single group and repeatedly performing a procedure which involves:

selecting a group and color for which a difference between maximum and minimum values of grayscale levels of subpixels is largest from one or more groups of current interest, and grouping pixels belonging to the selected group into two groups depending on grayscale levels of subpixels associated with the selected color.

10. The display device according to claim 7, wherein said N pixels include eight pixels,

wherein said M datasets include four datasets each including three representative values, and

wherein, in said pre-process, said representative-values calculation circuit generates Y data, Cr data and Cb data for each of said eight pixels by performing a YCrCb transform on image data of said eight pixels, calculates eight first representative values from data selected from the Y data, Cr data and Cb data of said eight pixels, said selected data having a largest difference between maximum and minimum values, and calculates four second representative values from the remaining two of the Y data, Cr data and Cb data of said eight pixels, each of said four datasets including two of said eight first representative values and one of said four second representative values.

11. An image processing circuit, comprising:

a representative-values calculation circuit configured to generate M datasets each including a plurality of representative values by performing a pre-process on image data associated with said N pixels, M being a natural number more than one and less than N; and

an all-combinations comparing compression circuit configured to calculate correlations between two datasets selected from said M datasets for all possible combinations of the two datasets, to select a compression process from a plurality of compression processes in response to the calculated correlations, and to generate said compressed imaged data by compressing said M datasets by using said selected compression process.

12. The image processing circuit according to claim 11, wherein, in said pre-process, said representative-values calculation circuit performs grouping of said N pixels into M groups which are associated with said M datasets, respectively, and calculates the representative values included in each of said M datasets, based on image data of pixels belonging to associated one of said M groups.

13. The image processing circuit according to claim 12, wherein each of said N pixels includes a subpixel associated with a first color, a subpixel associated with a second color and a subpixel associated with a third color,

wherein the grouping of said N pixels into said M groups is achieved by initially grouping said N pixels into a single group and repeatedly performing a procedure which involves:

selecting a group and color for which a difference between maximum and minimum values of grayscale levels of subpixels is largest from one or more groups of current interest, and grouping pixels belonging to the selected group into two groups depending on grayscale levels of subpixels associated with the selected color.

14. The image processing circuit according to claim 11, wherein said N pixels include eight pixels,

wherein said M datasets include four datasets each including three representative values, and

wherein, in said pre-process, said representative-values calculation circuit generates Y data, Cr data and Cb data for each of said eight pixels by performing a YCrCb transform on image data of said eight pixels, calculates eight first representative values from data selected from the Y data, Cr data and Cb data of said eight pixels, said selected data having a largest difference between maximum and minimum values, and calculates four second representative values from the remaining two of the Y data, Cr data and Cb data of said eight pixels, each of said four datasets including two of said eight first representative values and one of said four second representative values.

15. An image processing method, comprising:

generating M datasets each including a plurality of representative values by performing a pre-process on image data associated with said N pixels, M being a natural number more than one and less than N;

calculating correlations between two datasets selected from said M datasets for all possible combinations of the two datasets;

selecting a compression process from a plurality of compression processes in response to the calculated correlations; and

generating said compressed imaged data by compressing said M datasets by using said selected compression process.