Image signal processing apparatus, image signal processing method, image display apparatus, television receiver, and electronic device

• US 8,902,319 B2
• Filed: 05/28/2009
• Issued: 12/02/2014
• Est. Priority Date: 08/22/2008
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Ishihara, Tomoyuki
• Primary Examiner(s): Perungavoor, Sath V
• Assistant Examiner(s): Anderson, Matthew J
• Application Number:
  US12/737,710
• Publication Number:
  US 20110128449A1
• Time in Patent Office: 2,014 Days
• US Class Current: 348/208.4
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 2320/0261 in the context of movement of objects on the screen or movement of the observer relative to the screen
• CPC Class Codes: G09G 2320/0271 Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
• CPC Class Codes: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 2320/103 Detection of image changes, e.g. determination of an index representative of the image change
• CPC Class Codes: G09G 2320/106 Determination of movement vectors or equivalent parameters within the image
• CPC Class Codes: G09G 2340/0435 Change or adaptation of the frame rate of the video stream
• CPC Class Codes: G09G 2340/16 Determination of a pixel data signal depending on the signal applied in the previous frame
• 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 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers
• CPC Class Codes: H04N 5/142 Edging; Contouring
• CPC Class Codes: H04N 5/144 Movement detection for video coding H04N19/503; analysis of motion in general G06T7/20
• CPC Class Codes: H04N 5/66 Transforming electric information into light information scanning details H04N3/00
• CPC Class Codes: H04N 5/782 on tape
• CPC Class Codes: H04N 5/85 on discs or drums

Abstract

An image signal processing apparatus includes: a basic movement level finding section for detecting a movement level of a video image; a timing controller for dividing one frame period into a plurality of periods containing a sub-frame A period and a sub-frame B period; a sub-frame A image signal generating section for subjecting, to a smoothing process, image signals which are supplied to pixels, in the sub-frame A period, in accordance with the movement level of the video image; a sub-frame B image signal generating section for subjecting, to an emphasizing process, image signals which are supplied to pixels, in the sub-frame B period, in accordance with the movement level of the video image; and an applied movement level finding section for finding, from a movement level of a video image of a current frame period and a movement level of a video image of a previous frame period, an applied movement level which is applied to the sub-frame A image signal generating section and/or the sub-frame B image signal generating section.

Claims

1. An image signal processing apparatus provided in an image display apparatus for displaying an image, in accordance with image signals supplied to respective pixels, for every frame period corresponding to image signals for one (1) screen, the image signal processing apparatus comprising:

a movement level detector section which detects a first movement level of a video image corresponding to a current frame period, by comparing (i) image signals corresponding to the current frame period with (ii) image signals corresponding to a previous frame period followed by the current frame period;

a dividing section which divides one (1) frame period into a plurality of periods containing at least one sub-frame A period and at least one sub-frame B period;

a first image processing section which carries out a smoothing process in the at least one sub-frame A period, in accordance with a second movement level, with respect to input image signals to be supplied to respective pixels;

a second image processing section which carries out an emphasis process in the at least one sub-frame B period, in accordance with the second movement level, with respect to input image signals to be supplied to respective pixels; and

a movement level finding section which finds the second movement level from (i) the first movement level of the video image corresponding to the current frame period and (ii) a previous movement level of a video image corresponding to the previous frame period.

2. The image signal processing apparatus as set forth in claim 1, further comprising:

a retaining section which retains the second movement level found by the movement level finding section,

the movement level finding section configured to find the second movement level by using the second movement level retained by the retaining section as the previous movement level.

3. The image signal processing apparatus as set forth in claim 2, wherein the first image processing section and the second image processing section which carry out the smoothing process and the emphasis process, at respective processing intensities which vary depending on the second movement level found by the movement level finding section.

4. The image signal processing apparatus as set forth in claim 3, wherein, if Mc<

Mh, the movement level finding section supplies to the first image processing section and the second image processing section, as the second movement level, an average or a weighted average of Mc and Mh, where Mc is the first movement level, and Mh is the second movement level retained by the retaining section.

5. The image signal processing apparatus as set forth in claim 3, wherein, if Mc≧

Mh, the movement level finding section supplies Mc to the first image processing section and the second image processing section, as the second movement level, where Mc is the first movement level, and Mh is the second movement level retained by the retaining section.

18. An image display apparatus comprising an image signal processing apparatus recited in claim 1.

19. A television receiver comprising an image display apparatus recited in claim 18.

20. An electronic device comprising an image display apparatus recited in claim 18.

6. An image signal processing apparatus provided in an image display apparatus for displaying an image, in accordance with image signals supplied to respective pixels, for every frame period corresponding to image signals for one (1) screen, the image signal processing apparatus comprising:

a dividing section which divides one (1) frame period into a plurality of periods containing at least one sub-frame A period and at least one sub-frame B period;

a first image processing section which carries out a smoothing process with respect to input image signals to be supplied to respective pixels, in the at least one sub-frame A period; and

a second image processing section which carries out an emphasis process with respect to input image signals to be supplied to respective pixels, in the at least one sub-frame B period;

said first image processing section configured to carry out the smoothing process by use of an intergradation width which is set such that each of the input image signals which have been subjected to the smooth process has a smaller signal level as it is closer to a maximum signal level or a minimum signal level of image signals which the image display apparatus can display.

7. The image signal processing apparatus as set forth in claim 6, wherein, in a case where the second image processing section (i) carries out, with respect to the input image signals, an emphasis process by carrying out a smooth process and (ii) then supplies resultant signals to the image display apparatus, said second image processing section carries out the smoothing process by use of an intergradation width which is set such that each of the input image signals which have been subjected to the emphasis process has a smaller signal level as it is closer to a maximum signal level or a minimum signal level of image signals which the image display apparatus can display.

8. The image signal processing apparatus as set forth in claim 6, further comprising:

a temperature detector section which detects a temperature in the image signal processing apparatus,

said first image processing section carrying out the smoothing process by use of an intergradation width which is set such that each of the input image signals which have been subjected to the smoothing process has a smaller signal level as a temperature detected by the temperature detector section is lower than a predetermined temperature.

9. The image signal processing apparatus as set forth in claim 6, further comprising:

a temperature detector section which detects a temperature in the image signal processing apparatus, wherein

said second image processing section carrying out the smoothing process by use of an intergradation width which is set such that each of the input image signals which have been subjected to the emphasis process has a smaller signal level as a temperature detected by the temperature detector section is lower than a predetermined temperature.

10. An image signal processing method for causing an image display apparatus to display an image, in accordance with image signals supplied to respective pixels, for every frame period corresponding to image signals for one (1) screen, the image signal processing method comprising the steps of:

(a) detecting a first movement level of a video image corresponding to a current frame period, by comparing (i) image signals corresponding to the current frame period with (ii) image signals corresponding to a previous frame period followed by the current frame period;

(b) dividing one (1) frame period into a plurality of periods containing at least one sub-frame A period and at least one sub-frame B period;

(c) carrying out a smoothing process in the at least one sub-frame A period, in accordance with a second movement level, with respect to input image signals to be supplied to respective pixels;

(d) carrying out an emphasis process in the at least one sub-frame B period, in accordance with the second movement level, with respect to input image signals to be supplied to respective pixels; and

(e) finding the second movement level from (i) the first movement level of the video image corresponding to the current frame period and (ii) a previous movement level of a video image corresponding to the previous frame period.

11. The image signal processing method as set forth in claim 10, further comprising the step of:

(f) retaining, in a retaining section, the second movement level found in the step of (e),

in the step of (e), the second movement level being found by use of the second movement level retained by the retaining section as the previous movement level.

12. The image signal processing method as set forth in claim 11, wherein, in the steps of (c) and (d), the smoothing process and the emphasis process are carried out at respective processing intensities which vary depending on the second movement level found in the step of (e).

13. The image signal processing method as set forth in claim 12, wherein if Mc<

Mh, a simple average or a weighted average of Mc and Mh is supplied to the steps of (c) and (d), as the second movement level, in the step of (e), where Mc is the first movement level, and Mh is the second movement level retained by the retaining section.

14. The image signal processing method as set forth in claim 12, wherein, if Mc≧

Mh, Mc is supplied to the steps of (c) and (d), as the second movement level, in the step of (e), where Mc is the first movement level, and Mh is the second movement level retained by the retaining section.

15. An image signal processing method for causing an image display apparatus to display an image, in accordance with image signals supplied to respective pixels, for every frame period corresponding to image signals for one (1) screen, the image signal processing method comprising the steps of:

(g) dividing one (1) frame period into a plurality of periods containing at least one sub-frame A period and at least one sub-frame B period;

(h) carrying out a smoothing process with respect to input image signals to be supplied to respective pixels, in the at least one sub-frame A period; and

(i) carrying out an emphasis process with respect to input image signals to be supplied to respective pixels, in the at least one sub-frame B period;

in the step of (h), the smoothing process being carried out by use of an intergradation width which is set such that each of the input image signals which have been subjected to the smooth process has a smaller signal level as it is closer to a maximum signal level or a minimum signal level of image signals which the image display apparatus can display.

16. The image signal processing method as set forth in claim 15, wherein, in a case where in the step of (d), an emphasis process is carried out with respect to the input image signals by carrying out a smooth process and then resultant signals are supplied to the image display apparatus, the smoothing process is carried out in the step of (i) by use of an intergradation width which is set such that each of the input image signals which have been subjected to the emphasis process has a smaller signal level as it is closer to a maximum signal level or a minimum signal level of image signals which the image display apparatus can display.

17. The image signal processing method as set forth in claim 16, further comprising the step of (j) detecting a temperature in the image display apparatus,

in the step of (h), the smoothing process being carried out by use of an intergradation width which is set such that each of the input image signals which have been subjected to the smoothing process has a smaller signal level as a temperature detected in the step of (j) is lower than a predetermined temperature.