Video display apparatus for adjusting the degree of amplification of the input image according to image characteristics

• US 8,525,934 B2
• Filed: 01/23/2009
• Issued: 09/03/2013
• Est. Priority Date: 01/30/2008
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Fujine, Toshiyuki, Tetsuka, Yasushi, Niiyama, Ryuichi, Okui, Masahiro
• Primary Examiner(s): Natnael, Paulos M
• Application Number:
  US12/677,060
• Publication Number:
  US 20100328535A1
• Time in Patent Office: 1,684 Days
• Field of Search: 348/687, 348/688, 348/678, 348/679, 348/673, 348/558, 382167-169, 382/284, 382/254
• US Class Current: 348/687
• CPC Class Codes: G09G 2320/0238 Improving the black level
• CPC Class Codes: G09G 2320/062 Adjustment of illumination source parameters
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2320/0653 Controlling or limiting the speed of brightness adjustment of the illumination source
• CPC Class Codes: G09G 2320/066 for control of contrast
• 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 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• 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 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers
• CPC Class Codes: H04N 5/20 Circuitry for controlling amplitude response

Abstract

Brightness expression without solid white pattern is enabled, and video expression with an improved black level is achieved. A distortion module (5) reduces the luminance of a backlight source according to the histogram of the video signal so that the contrast may be a predetermined target one. A configuration design unit (13) sets the gain according to the luminance level (BL_reduced) of the backlight source selected by the distortion module (5). When setting the gain, the luminance level (BL_ref) for reference of the backlight source preset according to the video feature value is referenced. If the video feature value meets a predetermined condition, the input video signal is always amplified with the gain. If not, depending on the relation between the BL_reduced and the BL_ref, the input video signal is amplified or not.

Claims

1. A video image display apparatus that determines whether to amplify the input video image signal in accordance with a video image characteristic amount of an input video image signal, wherein

responsive to the video image characteristic amount meeting predetermined conditions, performing amplification on the input video image signal;

responsive to the video image characteristic amount failing to meet predetermined conditions, determining whether to perform amplification on the input video image signal, wherein

the video image characteristic amount is a frequency of a video signal that cannot be expressed in gradation due to the characteristics of a display portion when expanding an input signal with a predetermined amplification degree,

and the predetermined condition is that the frequency is a predetermined rate or less.

2. The video image display apparatus as defined in claim 1, wherein

the video image characteristic amount is average luminance of an input video image signal, and

the predetermined condition is that average luminance of the input video image is a predetermined value or less.

3. The video image display apparatus as defined in claim 2, wherein the predetermined value is changed in accordance with an image quality mode.

4. The video image display apparatus as defined in claim 1, wherein

the video image characteristic amount is average luminance of an input video image signal, and

the predetermined condition is that average luminance of the input video image is a first value or more and a second value or less.

5. The video image display apparatus as defined in claim 4, wherein the at least one of the first value and second value are changed in accordance with an image quality mode.

6. The video image display apparatus as defined in claim 1, wherein the predetermined conditions are changed in accordance with an image quality mode.

7. The video image display apparatus as defined in claim 1, wherein the predetermined rate is changed in accordance with an image quality mode.

10. The video image display apparatus as defined in claim 1, wherein

the video image characteristic amount is the maximum luminance and the minimum luminance of an input video image signal, and

the predetermined conditions are that the minimum luminance of the input video image signal is a first value or more and the maximum luminance of the input video image signal is a second value or less.

8. A video image display apparatus that determines whether to amplify the input video image signal in accordance with a video image characteristic amount of an input video image signal, wherein

responsive to the video image characteristic amount meeting predetermined conditions, performing amplification on the input video image signal;

responsive to the video image characteristic amount failing to meet predetermined conditions, determining whether to perform amplification on the input video image signal, wherein

the video image characteristic amount is average luminance of video signals and a frequency that cannot be expressed in gradation due to the characteristics of a display portion when expanding an input signal with a predetermined amplification degree, and

the predetermined conditions are that the average luminance is a predetermined value or less and the frequency is a predetermined rate or less.

9. A video image display apparatus that determines whether to amplify the input video image signal in accordance with a video image characteristic amount of an input video image signal, wherein

responsive to the video image characteristic amount meeting predetermined conditions, performing amplification on the input video image signal;

responsive to the video image characteristic amount failing to meet predetermined conditions, determining whether to perform amplification on the input video image signal, wherein

the video image characteristic amount is a frequency of a video signal that cannot be expressed in gradation due to the characteristics of a display portion when expanding an input signal with a predetermined amplification degree, and

the predetermined conditions are that average luminance of the input video image is a first value or more and a second value or less and additionally the average luminance is a predetermined value or less and the frequency is a predetermined rate or less.

11. A video image display apparatus that determines whether to amplify the input video image signal in accordance with a video image characteristic amount of an input video image signal, wherein

responsive to the video image characteristic amount meeting predetermined conditions, performing amplification on the input video image signal;

responsive to the video image characteristic amount failing to meet predetermined conditions, determining whether to perform amplification on the input video image signal,

the video image display apparatus including a display portion and a light source, inputs the video image signal to the display portion and irradiates a light from the light source on the display portion to display a video image,

wherein in a case where the video image characteristic amount does not meet predetermined conditions, the determination that the input video image signal is not amplified is responsive to when the light source luminance is the maximum luminance, and the determination that the input video image signal is amplified is responsive to when the light source luminance is lowered from the maximum luminance.

12. The video image display apparatus as defined in claim 11, wherein the amplification degree of a video image signal is determined based on light emission luminance of the light source.

13. The video image display apparatus as defined in claim 12, wherein the amplification degree of a video image signal is determined also considering a targeted light emission luminance value of the light source.

14. The video image display apparatus as defined in claim 13, wherein the targeted light emission luminance value of the light source is set to be a value greater than 100%.

15. A video image display apparatus that determines whether to amplify the input video image signal in accordance with a video image characteristic amount of an input video image signal, wherein

responsive to the video image characteristic amount meeting predetermined conditions, performing amplification on the input video image signal;

responsive to the video image characteristic amount failing to meet predetermined conditions, determining whether to perform amplification on the input video image signal,

the video image display apparatus including a display portion and a light source, inputs the video image signal to the display portion and irradiates a light from the light source on the display portion to display a video image,

wherein the amplification degree of a video image signal is determined based on light emission luminance of the light source, wherein the amplification degree of a video image signal, at the time when light emission luminance of the light source is at maximum, is set to be a value greater than a value capable of appropriately displaying an input video image signal of maximum luminance.