Electronic endoscope system with color-balance alteration process

• US 6,879,339 B2
• Filed: 10/22/2002
• Issued: 04/12/2005
• Est. Priority Date: 10/23/2001
• Status: Active Grant

• Current Assignee: Hoya Corporation
• Original Assignee: Pentax Corporation (Hoya Corporation)
• Inventors: Ozawa, Ryo
• Primary Examiner(s): Lee, Richard
• Application Number:
  US10/274,998
• Publication Number:
  US 20030076412A1
• Time in Patent Office: 903 Days
• Field of Search: H04/N00.7/18, 348/45, 348 65- 72, 600/101, 600/109, 600/113
• US Class Current: 348/71
• 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

An electronic endoscope system with a color-balance alteration system includes a video scope having a CCD image sensor for producing a frame of color image-pixel-signals composed of frames of red, green, and blue image-pixel-signals. In the color-balance alteration system, nine red signals are extracted from the frame of red image-pixel-signals, and the nine signals form a 3×3 matrix including a central signal, and the eight circumferential signals. All four sets of three signals are selected from the nine signals, and each set of three signals is composed of the central signal, and two neighbouring signals aligned with each other such that the central signal lies therebetween. When a signal level of the central signal is smaller than both signal levels of the two circumferential signals with respect to even one set of three signals, the signal level of signal is decreased.

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 at least two frames of different monochromatic image-pixel-signals, which comprises a color-balance alteration system including:

an extraction system that successively extracts a set of monochromatic image-pixel-signals from a frame of monochromatic image-pixel-signals, the set of monochromatic image-pixel-signals being composed of a central monochromatic image-pixel-signal, and neighbouring monochromatic image-pixel-signals surrounding said central monochromatic image-pixel-signal;

a selection system that selects all sets of three monochromatic image-pixel-signals from said set of monochromatic image-pixel-signals, each set of three monochromatic image-pixel-signals being composed of said central monochromatic image-pixel-signal, and two neighbouring monochromatic image-pixel-signals aligned with each other such that said central monochromatic image-pixel-signal lies therebetween;

a determination system that determines whether a signal level of said central monochromatic image-pixel-signal is smaller than signal levels of said two neighbouring monochromatic image-pixel-signals with respect to all said sets of three monochromatic image-pixel-signals; and

a decrease system that decreases the signal level of said central monochromatic image-pixel-signal when it is determined by said determination system that the signal level of said central monochromatic image-pixel-signal is smaller than both the signal levels of said two neighbouring monochromatic image-pixel-signals in at least one of the sets of three monochromatic image-pixel-signals.

2. An electronic endoscope system as set forth in claim 1, wherein said decrease system comprises a subtraction system that subtracts a predetermined level value from the signal level of said central monochromatic image-pixel-signal.

3. An electronic endoscope system as set forth in claim 1, wherein said decrease system comprises a multiplier system that multiplies the signal level of said central monochromatic image-pixel-signal by a predetermined factor less than one.

4. 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 composed of the frame of monochromatic image-pixel-signals processed by said color-balance alteration system; and

a monitor system that selectively displays a first image and a second image based on said first and second types of video signals, respectively.

5. An electronic endoscope system as set forth in claim 4, 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.

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