Automatic digital white-balancing circuit utilizing memory addresses to determine where white-balance correction is necessary

• US 5,298,979 A
• Filed: 12/11/1991
• Issued: 03/29/1994
• Est. Priority Date: 12/31/1990
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Sung H.
• Primary Examiner(s): Kostak, Victor R.
• Assistant Examiner(s): Murrell, Jeffrey S.
• Application Number:
  US07/804,735
• Time in Patent Office: 839 Days
• Field of Search: 358/29, 358/29 C, 358/30, 358/41
• US Class Current: 348/655
• CPC Class Codes: H04N 23/88 for colour balance, e.g. white-balance circuits or colour temperature control

Abstract

An automatic digital white-balancing circuit comprises multipliers, a color difference matrix, an encoder sampling part, a integrating memory part, a comparing part, and a microcomputer, wherein the multipliers multiply color separated digital signals by multiplying coefficients applied from the microcomputer, the sampling part samples Y signals and R-Y and B-Y color difference signals of the matrix part, the integrating memory part integrates the output data from the sampling part and stores in the memory, and the comparing part decides whether the integrated data is included in a white balance adjusting region. Thus, the white balance can be adjusted even in a digital video camera as well as in an analogue video camera.

Claims

1. An automatic white balance circuit, comprising:

means for receiving video signals comprised of a luminance signal and color signals representative of a red color signal, a green color signal and a blue color signal;

multiplier means for multiplying selected ones of said color signals with corresponding ones of multiplying coefficients;

matrix means for generating first color-difference signals in dependence upon the outputs of said multiplier means;

encoder means for encoding said luminance signal and said first color-difference signals;

sampling means for sampling said first color-difference signals in dependence upon a sampling frequency to provide sampled signals;

means for generating second color-difference signals by combining said selected ones of said color signals with said luminance signal;

means for determining whether said second color-difference signals are in a white balance adjusting region to provide a balance enable signal;

integrating memory means for integrating the sampled signals in dependence upon said balance enable signal, and storing the integrated signals in accordance with designated addresses; and

processor means coupled to receive said integrated signals and said balance enable signal, for providing said designated addresses and said multiplying coefficients to control white balance of said video signals.

2. The automatic white balance circuit as claimed in claim 1, wherein said color signals and said luminance signal are digital signals.

3. An automatic white balance circuit, comprising:

means for receiving a luminance signal and color signals representative of a red color signal, a green color signal and a blue color signal;

multiplier means for multiplying said color signals in dependence upon a plurality of multiplying coefficients;

matrix means for providing R-Y and B-Y color difference signals in dependence upon the outputs of said multiplier means;

encoder means for encoding said luminance signal and said R-Y and B-Y color difference signals;

sampling means for sampling said R-Y and B-Y color difference signals in dependence upon a sampling frequency to provide sampled signals;

comparing means for determining whether said R-Y and B-Y color signals are in a white balance adjusting region to provide a balance enable signal;

latching means for latching said sampled signals from said sampling means in dependence upon said balance enable signal to provide latched signals;

plural memory means having a plurality of addresses, for storing said latched signals at designated addresses in dependence upon a number of divisions of an image; and

processor means for generating said plurality of multiplying coefficients to control white balance of said image in dependence upon a reading of the latched signals stored in said designated addresses of said plural memory means, said processor means designating addresses of said plural memory means.

4. The automatic white balance circuit as claimed in claim 3, wherein said color signals and said luminance signal are digital signals.

5. An automatic white balance circuit, comprising:

means for receiving a luminance signal and color signals representative of a red color signal, a green color signal and a blue color signal;

multiplier means for multiplying said color signals in dependence upon a plurality of multiplying coefficients;

matrix means for providing R-Y and B-Y color difference signals in dependence upon the outputs of said multiplier means;

encoder means for encoding said luminance signal and said R-Y and B-Y color difference signals;

sampling means for sampling said R-Y and B-Y color difference signals in dependence upon a sampling frequency to provide sampled signals;

a plurality of integrators for integrating said sampled signals to provide integrated signals;

a plurality of memories for storing said integrated signals corresponding to a number of divisions of an image;

means for providing white balance adjusting signals by reading the stored signals from said plurality of memories in designated addresses, and determining whether the read signals are in a white balance adjusting region; and

processor means for generating said designated addresses for said plurality of memories, and for generating said plurality of multiplying coefficients to control white balance of said image in dependence upon reception of said white balance adjusting signals.

6. An automatic white balance circuit, comprising:

means for receiving video signals comprised of a luminance signal and color signals;

multiplier means for multiplying selected colors of said color signals with corresponding ones of white balance control coefficients to provide multiplied color signals;

matrix means for providing color-difference signals in dependence upon said multiplied color signals;

encoder means for encoding said luminance signal and said color-difference signals to provide white balance luminance and chrominance signals; and

white balance controller means for automatically controlling white balance of said video signals in dependence upon an illumination condition of an illuminating object by determining whether said color-difference signals and said luminance signal are in a white balance adjusting region to provide said white balance control coefficients, said white balance controller means comprising;

sampling means for sampling said color-difference signals in dependence upon a sampling clock frequency to provide sampled signals;

first generating means for generating a first color-difference signal in dependence upon reception of a first color of said color signals and said luminance signal;

second generating means for generating a second color-difference signal in dependence upon reception of a second color of said color signals and said luminance signal;

comparing means for comparing said first and second color-difference signals and said luminance signal to provide a compared signal;

switching means for enabling transmission of said sampled signals in dependence upon said compared signal to provide transmitted sampling signals;

means for integrating said transmitted sampling signals to provide integrated signals, and for storing said integrated signals in designated addresses; and

processor means for providing said designated addresses and said white balance control coefficients in dependence upon reception of said integrated signals.

7. The automatic white balance circuit as claimed in claim 6, wherein said luminance signal and said color signals representative of said red color signal, said green color signal and said blue color signal are digital signals.

8. An automatic white balance circuit, comprising:

means for receiving video signals comprised of a luminance signal and color signals;

multiplier means for multiplying selected colors of said color signals with corresponding ones of white balance control coefficients to provide multiplied color signals;

matrix means for providing color-difference signals in dependence upon said multiplied color signals;

encoder means for encoding said luminance signal and said color-difference signals to provide white balance luminance and chrominance signals; and

white balance controller means for automatically controlling white balance of said video signals in dependence upon an illumination condition of an illuminating object by determining whether said color-difference signals and said luminance signal are in a white balance adjusting region to provide said white balance control coefficients, said white balance controller means comprising;

sampling means for sampling said color-difference signals and said luminance signal in dependence upon a sampling clock frequency to provide corresponding sampled color-difference signals and sampled luminance signal;

comparing means for comparing said sampled color-difference signals and said sampled luminance signal to provide a latching signal in dependence upon a control signal;

latch means for temporarily storing said sampled color-difference signals, and for latching the stored sampled color-difference signals in dependence upon said latching signal;

integrating means for integrating the latched color-difference signals to provide corresponding integrated color-difference signals;

memory means having first and second memory groups for storing each of corresponding components of said integrated color-difference signals in designated addresses; and

processor means for providing said designated addresses, said control signal and said white balance control coefficients via a plurality of registers in dependence upon reception of the stored integrated color-difference signals.

9. The automatic white balance circuit as claimed in claim 8, wherein said luminance signal and said color signals representative of said red color signal, said green color signal and said blue color signal are digital signals.

10. A method for automatically controlling a white balance of video signals, comprising the steps of:

receiving said video signals comprised of a luminance signal and color signals;

multiplying selected colors of said color signals with corresponding ones of white balance control coefficients to provide multiplied color signals;

differentiating each of said multiplied color signals to provide first and second color-difference signals;

encoding said luminance signal and said first and second color-difference signals to provide white balance luminance and chrominance signals; and

automatically controlling white balance of said video signals in dependence upon an illumination condition of an illuminating object by determining whether said color-difference signals and said luminance signal are in a white balance adjusting region to provide said white balance control coefficients, wherein said white balance controlling step further comprises the steps of;

sampling said first and second color-difference signals in dependence upon a sampling clock frequency to provide sampled signals;

generating a third color-difference signal in dependence upon reception of a first color of said color signals and said luminance signal, and a fourth color-difference signal in dependence upon reception of a second color of said color signals and said luminance signal;

comparing said third and fourth color-difference signals and said luminance signal to provide a compared signal;

enabling transmission of said sampled signals in dependence upon said compared signal to provide transmitted sampling signals;

integrating said transmitted sampling signals to provide integrated signals, and for storing said integrated signals in designated addresses of a memory; and

generating said designated addresses and said white balance control coefficients in dependence upon reception of said integrated signals.

11. A method for automatically controlling a white balance of video signals, comprising:

receiving said video signals comprised of a luminance signal and color signals;

multiplying selected colors of said color signals with corresponding ones of white balance control coefficients to provide multiplied color signals;

differentiating each of said multiplied color signals to provide first and second color-difference signals;

encoding said luminance signal and said first and second color-difference signals to provide white balance luminance and chrominance signals; and

automatically controlling white balance of said video signals in dependence upon an illumination condition of an illuminating object by determining whether said color-difference signals and said luminance signal are in a white balance adjusting region to provide said white balance control coefficients, wherein said white balance controlling step further comprises the steps of;

sampling said first and second color-difference signals and said luminance signal in dependence upon a sampling clock frequency to provide corresponding first and second sampled color-difference signals and a sampled luminance signal;

comparing said first and second sampled color-difference signals and said sampled luminance signal to provide a latching signal in dependence upon a control signal;

temporarily storing said first and second sampled color-difference signals for latching the stored first and second sampled color-difference signals in dependence upon said latching signal;

integrating the first and second latched color-difference signals to provide corresponding first and second integrated color-difference signals;

storing said first and second integrated color-difference signals in designated addresses of a plurality of memories; and

generating said designated addresses, said control signal and said white balance control coefficients via a plurality of registers in dependence upon reception of the stored integrated color-difference signals.

12. An automatic white balance circuit, comprising:

means for receiving video signals comprised of chrominance signals and luminance signals;

means for adjusting selected color components of said chrominance signals with corresponding ones of white balance control coefficients to provide adjusted chrominance signals;

means for providing color-difference signals in dependence upon said adjusted chrominance signals; and

white balance controller means for automatically controlling white balance of said video signals in dependence upon illumination condition of an object by determining whether said color-difference signals and said luminance signals are in a white balance adjusting region to provide said white balance control coefficients, said white balance controller means comprising;

sampling means for sampling said luminance signals and said color-difference signals in dependence upon a sampling clock to provide sampled signals;

means for integrating said sampled signals to provide integrated signals, and for storing said integrated signals in designated addresses of a memory;

means for determining whether the stored integrated signals in designated addresses of said memory are in said white balance adjusting region to provide a white balance enabling signal; and

processor means for providing said designated addresses and said white balance control coefficients in dependence upon said white balance enabling signal.

13. An automatic white balance circuit, comprising:

means for receiving video signals comprised of chrominance signals and luminance signals;

means for adjusting selected color components of said chrominance signals with corresponding ones of white balance control coefficients to provide adjusted chrominance signals;

means for providing color-difference signals in dependence upon said adjusted chrominance signals; and

white balance controller means for automatically controlling white balance of said video signals in dependence upon illumination condition of an object by determining whether said color-difference signals and said luminance signals are in a white balance adjusting region to provide said white balance control coefficients, said white balance controller means comprising;

sampling means for sampling said color-difference signals and said luminance signals in dependence upon a sampling clock to provide corresponding sampled color-difference and luminance signals;

a plurality of integrators for integrating said sampled color-difference and luminance signals to provide integrated color-difference and luminance signals;

a plurality of memories having designated addresses, for storing said integrated color-difference and luminance signals in said designated addresses;

means for comparing the stored integrated color-difference and luminance signals to provide compared signals; and

processor means for selecting said designated addresses and for producing said white balance control coefficients via a plurality of registers in dependence upon reception of said compared signals.

14. An automatic white balance circuit, comprising:

means for receiving video signals comprised of chrominance signals and luminance signals;

means for adjusting selected color components of said chrominance signals with corresponding ones of white balance control coefficients to provide a plurality adjusted chrominance signals;

means for providing color-difference signals in dependence upon said adjusted chrominance signals; and

white balance controller means for automatically controlling white balance of said video signals in dependence upon illumination condition of an object by determining whether said color-difference signals and said luminance signals are in a white balance adjusting region to provide said white balance control coefficients, said white balance controller means comprising;

sampling means for sampling said color-difference signals and said luminance signals in dependence upon a sampling clock to provide sampled color-difference and luminance signals;

comparing means for comparing said sampled color-difference and luminance signals to provide a latching signal in dependence upon a control signal;

means for temporarily storing said sampled color-difference signals, and latching the stored sampled color-difference signals in dependence upon said latching signal, and for integrating the latched color-difference signals to provide corresponding integrated color-difference signals;

memory means having first and second memory groups with designated addresses, for storing each of corresponding components of said integrated color-difference signals in said designated addresses; and

processor means for selecting said designated addresses, and for producing said control signal and said white balance control coefficients via a plurality of registers in dependence upon reception of the stored integrated color-difference signals.