Electronic endoscope system with color-balance alteration process

• US 7,050,086 B2
• Filed: 06/25/2002
• Issued: 05/23/2006
• Est. Priority Date: 06/26/2001
• Status: Active Grant

• Current Assignee: Hoya Corporation
• Original Assignee: Pentax Corporation (Hoya Corporation)
• Inventors: Ozawa, Ryo
• Primary Examiner(s): Le, Vu
• Assistant Examiner(s): CZEKAJ, DAVID J
• Application Number:
  US10/178,534
• Publication Number:
  US 20020196335A1
• Time in Patent Office: 1,428 Days
• Field of Search: 348/70, 348/650, 348/635, 382/274, 382/275, 600/101, 600/109, 600/112
• US Class Current: 348/70
• CPC Class Codes: A61B 1/045 Control thereof
• CPC Class Codes: H04N 23/88 for colour balance, e.g. white-balance circuits or colour temperature control

Abstract

In an electronic endoscope system including a video scope having a solid-state image sensor that successively produces a frame of red, green, and blue image-pixel signals, a difference value is calculated between a value of each of corresponding central red, green, and blue image-pixel signals and an average of values of circumferential image-pixel signals surrounding the central image-pixel signal. When the respective values of the central red and green image-pixel signals are smaller than the corresponding averages of values, they are decreased in proportion to the absolute values of the corresponding difference values. When the value of the central blue image-pixel signal is smaller than the corresponding average of values, it is increased in proportion to the absolute value of the corresponding difference value.

Claims

1. An electronic endoscope system including a video scope having a solid-state image sensor that successively produces a frame of color image-pixel signals composed of two frames of first-type-single-color image-pixel signals and second-type-single-color image-pixel signals, said electronic endoscope system comprising:

a calculation system that calculates a first difference value between a first value of a central first-type-single-color image-pixel signal for a central first-type-single-color image-pixel and a first average of values of circumferential first-type-single-color image-pixel signals for pixels surrounding said central first-type-single-color image-pixel, and a second difference value between a second value of a corresponding central second-type-single-color image-pixel signal for a central second-type-single-color image-pixel and a second average of values of circumferential second-type-single-color image-pixel signals for pixels surrounding said central second-type-single-color image-pixel; and

a color-balance alteration system that alters said first value when it is smaller than said first average of values, and that alters said second value when it is smaller than said second average of values, such that one of said first and second values is increased in proportion to an absolute value of a corresponding one of said first and second difference values, and such that the remaining one of said first and second values is decreased in proportion to an absolute value of the remaining corresponding one of said first and second difference values.

2. An electronic endoscope system as set forth in claim 1, further comprising:

a first video signal production system that produces a first type of video signal based on the frame of color image-pixel signals;

a second video signal production system that produces a second type of video signal based on the frame of color image-pixel signals processed by said color-balance alteration system; and

a monitor system configured to selectively display a first image and a second image based on said first and second types of video signals, respectively.

3. An electronic endoscope system as set forth in claim 2, further comprising:

a display-mode selection system that selects either a first display mode or a second display mode; and

a display control system that displays said first image on said monitor system based on said first type of video signal when the first display mode is selected by said display-mode selection system, and that displays said second image on said monitor system based on said second type of video signal when the second display mode is selected by said display-mode selection system.

4. An electronic endoscope system as set forth in claim 3, further comprising:

a disablement system that disables said color-balance alteration system when the first display mode is selected by said display-mode selection system; and

an enablement system that enables said color-balance alteration system when the second display mode is selected by said display-mode selection system.

5. An electronic endoscope system including a video scope having a solid-state image sensor that successively produces a frame of color image-pixel signals composed of three frames of first-type-single-color image-pixel signals, second-type-single-color image-pixel signals, and third-type-single-color image-pixel signals, said electronic endoscope system comprising:

a calculation system that calculates a first difference value between a first value of a central first-type-single-color image-pixel signal for a central first-type-single-color image-pixel and a first average of values of circumferential first-type-single-color image-pixel signals for pixels surrounding said central first-type-single-color image-pixel, a second difference value between a second value of a corresponding central second-type-single-color image-pixel signal for a central second-type-signal-color image-pixel and a second average of values of circumferential second-type-single-color image-pixel signals for pixels surrounding said central second-type-single-color image-pixel, and a third difference value between a third value of a corresponding central third-type-single-color image-pixel signal for a central third-type-signal-color image-pixel and a third average of values of circumferential third-type-single-color image-pixel signals for pixels surrounding said central third-type-single-color image-pixel; and

a color-balance alteration system that alters said first value when it is smaller than said first average of values, that alters said second value when it is smaller than said second average of values, and that alters said third value when it is smaller than said third average of values, such that two of said first, second, and third values are respectively increased in proportion to absolute values of corresponding ones of said first, second, and third difference values, and such that the remaining one of said first, second, and third values is decreased in proportion to absolute values of the remaining corresponding one of said first, second, and third difference values.

6. An electronic endoscope system as set forth in claim 5, further comprising:

a first video signal production system that produces a first type of video signal based on the frame of color image-pixel signals;

a second video signal production system that produces a second type of video signal based on the frame of color image-pixel signals processed by said color-balance alteration system; and

a monitor system configured to selectively display a first image and a second image based on said first and second types of video signals, respectively.

7. An electronic endoscope system as set forth in claim 6, further comprising:

a display-mode selection system that selects either a first display mode or a second display mode; and

a display control system that displays said first image on said monitor system based on said first type of video signal when the first display mode is selected by said display-mode selection system, and that displays said second image on said monitor system based on said second type of video signal when the second display mode is selected by said display-mode selection system.

8. An electronic endoscope system as set forth in claim 7, further comprising:

a disablement system that disables said color-balance alteration system when the first display mode is selected by said display-mode selection system; and

an enablement system that enables said color-balance alteration system when the second display mode is selected by said display-mode selection system.

9. An electronic endoscope system comprising:

a video scope having a solid-state image sensor that successively produces a first type frame of color image-pixel signals;

an image-signal processing unit including a first video signal production system that produces a first type of video signal based on the first type frame of color image-pixel signals;

a first monitor system that displays a first image based on said first type of video signal;

a color-balance alteration process unit including a color image-pixel-signal production system that successively produces a second type frame of color image-pixel signals based on said first type of video signal, a calculation system that calculates a difference value between a value of a central color image-pixel signal for a central color image-pixel, included in said second type frame, and an average of values of circumferential color image pixel signals for pixels surrounding said central color image-pixel, a color-balance alteration system that alters the value of said central color image-pixel signal in accordance with the difference value calculated by said calculation system, whereby said second type of color image-pixel signals is subjected to a color-balance alteration process by said color-balance alteration system, and a second video signal production system that produces a second type of video signal based on the second type frame of color image-pixel signals subjected to said color-balance alteration process; and

a second monitor system that displays a second image based on said second type of video signals,

wherein said color-balance alteration process unit further includes a third video signal production system that produces a third type of video signal based on the second type frame of color image-pixel signals not subjected to said color-balance alteration process, and said second monitor system is configured to selectively display a third image based on said third type of video signals.

10. An electronic endoscope system as set forth in claim 9, wherein said color-balance alteration unit further includes a display-mode selection system that selects either a first display mode or a second display mode;

and

a display control system that displays said second image on said second monitor system based on said second type of video signal when the first display mode is selected by said display-mode selection system, and that displays said third image on said second monitor system based on said third type of video signal when the second display mode is selected by said display-mode selection system.

11. An electronic endoscope system as set forth in claim 10, wherein said color-balance alteration unit further includes a disablement system that disables said color-balance alteration system when the first display mode is selected by said display-mode selection system;

and

an enablement system that enables said color-balance alteration system when the second display mode is selected by said display-mode selection system.

12. An electronic endoscope system comprising:

a video scone having a solid-state image sensor that successively produces a first type frame of color image-pixel signals;

an image-signal processing unit including a first video signal production system that produces a first type of video signal based on the first type frame of color image-pixel signals;

a first monitor system that displays a first image based on said first type of video signal;

a color-balance alteration process unit including a color image-pixel-signal production system that successively produces a second type frame of color image-pixel signals based on said first type of video signal, a calculation system that calculates a difference value between a value of a central color image-pixel signal for a central color image-pixel, included in said second type frame, and an average of values of circumferential color image-pixel signals for pixels surrounding said central color image-pixel, a color-balance alteration system that alters the value of said central color image-pixel signal in accordance with the difference value calculated by said calculation system, whereby said second type of color image-pixel signals is subjected to a color-balance alteration process by said color-balance alteration system, and a second video signal production system that produces a second type of video signal based on the second type frame of color image-pixel signals subjected to said color-balance alteration process; and

a second monitor system that displays a second image based on said second type of video signals,

wherein said color-balance alteration unit further includes a clock-pulse generator that produces a series of clock pulses, the successive production of said second type frame of color image-pixel signals by said color image-pixel-signal production system, the calculation of said difference value by said calculation system, and the alteration of said central color image-pixel signal by said color-balance alteration system being performed based on said clock pulses, and a clock-pulse-frequency change system that changes a frequency of said clock pulses in accordance with a variation in a spatial frequency of said first image.

13. An electronic endoscope system comprising:

a video scope having a solid-state image sensor that successively produces a first type frame of color image-pixel signals;

an image-signal processing unit including a first video signal production system that produces a first type of video signal based on the first type frame of color image-pixel signals;

a first monitor system that displays a first image based on said first type of video signal;

a color-balance alteration process unit including a color image-pixel-signal production system that successively produces a second type frame of color image-pixel signals based on said first type of video signal, a calculation system that calculates a difference value between a value of a central color image-pixel signal for a central color image-pixel, included in said second type frame, and an average of values of circumferential color image signals for pixels surrounding said central color image-pixel, a color-balance alteration system that alters the value of said central color image-pixel signal in accordance with the difference value calculated by said calculation system, whereby said second type of color image-pixel signals is subjected to a color-balance alteration process by said color-balance alteration system, and a second video signal production system that produces a second type of video signal based on the second type frame of color image-pixel signals subjected to said color-balance alteration process; and

a second monitor system that displays a second image based on said second type of video signals,

wherein said color-balance alteration unit further includes a restriction system that restricts an area, to be subjected to said color-balance alteration process, on a display area of said second monitor system, such that character information, displayed on the display area of said second monitor system, is prevented from being subjected to said color-balance alteration process.

14. An electronic endoscope system as set forth in claim 13, wherein said color-balance alteration unit further includes a restriction-area change system that changes the area restricted by said restriction system.

15. An electronic endoscope system including a video scope having a solid-state image sensor that successively produces a frame of color image-pixel signals composed of two frames of first-type-single-color image-pixel signals and second-type-single-color image-pixel signals, said electronic endoscope system comprising:

a calculation system that calculates a difference value between a first value of a central first-type-single-color image-pixel signal for a central first-type-single-color image-pixel and an average of values of circumferential first-type-single-color image-pixel signals for pixels surrounding said central first-type-single-color image-pixel, and a difference value between a value of a corresponding central second-type-single-color image-pixel signal for a central second-type-single-color image-pixel and an average of values of circumferential second-type-single-color image-pixel signals for pixels surrounding said central second-type-single-color image-pixel;

a comparison system that compares the value of said central first-type-single-color image-pixel signal and the value of said central second-type-single-color image-pixel signal with each other, to thereby determine which values value is smaller; and

a color-balance alteration system that decreases only a smaller one of said two values in proportion to an absolute value of the corresponding difference value when the smaller one of said two values is smaller than the corresponding average of values.

16. An electronic endoscope system as set forth in claim 15, further comprising:

a first video signal production system that produces a first type of video signal based on the frame of color image-pixel signals;

a second video signal production system that produces a second type of video signal based on the frame of color image-pixel signals processed by said color-balance alteration system; and

a monitor system configured to selectively display a first image and a second image based on said first and second types of video signals, respectively.

17. An electronic endoscope system as set forth in claim 16, further comprising:

a display-mode selection system that selects either a first display mode or a second display mode; and

a display control system that displays said first image on said monitor system based on said first type of video signal when the first display mode is selected by said display-mode selection system, and that displays said second image on said monitor system based on said second type of video signal when the second display mode is selected by said display-mode selection system.

18. An electronic endoscope system as set forth in claim 17, further comprising:

a disablement system that disables said color-balance alteration system when the first display mode is selected by said display-mode selection system; and

an enablement system that enables said color-balance alteration system when the second display mode is selected by said display-mode selection system.

19. An electronic endoscope system including a video scope having a solid-state image sensor that successively produces a frame of color image-pixel signals composed of three frames of first-type-single-color image-pixel signals, second-type-single-color image-pixel signals and third-type-single-color image-pixel signals, the electronic endoscope system comprising:

a calculation system that calculates a difference value between a first value of a central first-type-single-color image-pixel signal for a central first-type-single-color image-pixel and an average of values of circumferential first-type-single-color image-pixel signals for pixels surrounding said central first-type-single-color image-pixel, that calculates a difference value between a value of a corresponding central second-type-single-color image-pixel signal for a central second-type-single-color image-pixel and an average of values of circumferential second-type-single-color image-pixel signals for pixels surrounding said central second-type-single-color image-pixel, and that calculates a difference value between a value of a corresponding central third type-single-color image-pixel signal for a central third-type-single-color image-pixel and an average of values of circumferential third-type-single-color image-pixel signals for pixels surrounding said central third-type-single-color image-pixel;

a comparison system that compares the value of said central first-type-single-color image-pixel signal, that compares the value of said central second-type-single-color image-pixel signals, and that compares the value of said central third-type-single-color image-pixel signals with each other, to thereby determine a maximum one of said three values; and

a color-balance alteration system that decreases the respective two values, except for the maximum value, in proportion to absolute values of the corresponding difference values when each of said two values is smaller than the corresponding average of values.

20. An electronic endoscope system as set forth in claim 19 further comprising:

a first video signal production system that produces a first type of video signal based on the frame of color image-pixel signals;

a second video signal production system that produces a second type of video signal based on the frame of color image-pixel signals processed by said color-balance alteration system; and

a monitor system configured to selectively display a first image and a second image based on said first and second types of video signals, respectively.

21. An electronic endoscope system as set forth in claim 20, further comprising:

a display-mode selection system that selects either a first display mode or a second display mode; and

a display control system that displays said first image on said monitor system based on said first type of video signal when the first display mode is selected by said display-mode selection system, and that displays said second image on said monitor system based on said second type of video signal when the second display mode is selected by said display-mode selection system.

22. An electronic endoscope system as set forth in claim 21, further comprising:

a disablement system that disables said color-balance alteration system when the first display mode is selected by said display-mode selection system; and

an enablement system that enables said color-balance alteration system when the

second display mode is selected by said display-mode selection system.