Endoscope with smear extraction and correction

• US 5,631,695 A
• Filed: 07/26/1994
• Issued: 05/20/1997
• Est. Priority Date: 10/18/1993
• Status: Expired due to Term

• Current Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Original Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Inventors: Nakamura, Kazunari, Hiyama, Keiichi
• Primary Examiner(s): Chin, Tommy P.
• Assistant Examiner(s): LIN, BRYAN T
• Application Number:
  US08/280,468
• Time in Patent Office: 1,029 Days
• Field of Search: 348/65, 348/67, 348/68, 348/74, 348/248, 348/249
• US Class Current: 348/65
• CPC Class Codes: H04N 23/555 for picking-up images in sites, inaccessible due to their dimensions or hazardous conditions, e.g. endoscopes or borescopes
• CPC Class Codes: H04N 25/625 for the control of smear
• CPC Class Codes: H04N 25/71 Charge-coupled device [CCD] sensors; Charge-transfer registers specially adapted for CCD sensors

Abstract

An image processing apparatus for an endoscope including a smearing component extraction device for extracting a smearing component caused by a high luminance light beam from an original image composed of an image signal of a subject to be imaged. The image processing apparatus also includes a device for correcting the original image composed of the image signal by use of the signal of the smearing component extracted by the smearing component extraction device and reduces or eliminates smearing when a laser treatment is carried out to thereby improve the quality of an image to be observed.

Claims

1. An image processing apparatus for an endoscope, comprising:

smearing component extraction means for extracting a smearing component caused by a high luminance light beam from an original image composed of an image signal of a subject to be imaged, wherein said smearing component extraction means takes predetermined correlations with respect to luminance information in respective directions in which smearing occurs in the original image composed of said image signal, removes components having a small correlation value in said directions, and then extracts a smearing component of an image signal output from an imaging means which receives a light beam from a subject and subjects the light beam to photo-electric conversion or a smearing component of an image signal output from image record/reproduction means for recording an output from said imaging means; and

correction means for correcting said original image composed of said image signal by use of the signal of said smearing component extracted by said smearing component extraction means.

2. An image processing apparatus for an endoscope according to claim 1, wherein said smearing component extraction means removes components having a luminance value equal to or greater than a predetermined value and then detects said smearing component.

3. An image processing apparatus for an endoscope according to claim 1, wherein said smearing component extraction means determines correlation values indicating whether or not a predetermined value for making luminance levels substantially uniform appears in respective directions in which smearing occurs as said predetermined correction and extracts a portion where said correlation values are equal to or greater than a predetermined level as a smearing component.

4. An image processing apparatus for an endoscope according to claim 3, wherein said smearing component extraction means determines average values of luminance in respective directions in which said smearing occurs as said correlation values and extracts a high luminance portion having a luminance level equal to or greater than a predetermined level from said average values as a smearing component.

5. An image processing apparatus for an endoscope, comprising:

smearing component extraction means for extracting a smearing component caused by a high luminance light beam from an original image composed of an electric signal output from imaging means for receiving a light beam and subjecting said received light beam to photoelectric conversion, wherein said smearing component extraction means determines average values of luminance information in respective transfer directions and extracts a portion where said average values are equal to or greater than a predetermined value as a smearing component; and

correction means for correcting said electric signal output from said imaging means by use of the signal of said smearing component extracted by said smearing component extraction means.

6. An image processing apparatus for an endoscope according to claim 5, wherein said imaging means is a solid-state imaging device for transferring and outputting charge obtained by subjecting a received light beam to photo-electric conversion.

7. An image processing apparatus for an endoscope according to claim 6, wherein said solid-state imaging device is a line transfer type device and includes a photosensitive/transfer unit sharing a photosensitive unit for obtaining charge by subjecting an incident light beam to photoelectric conversion and a transfer unit for transferring said charge accumulated by said photosensitive unit, a vertical scan circuit for outputting a signal for reading said charge to said photosensitive/transfer unit, and an output unit for outputting said charge read by said vertical scan circuit and transferred from said photosensitive/transfer unit.

8. An image processing apparatus for an endoscope according to claim 5, wherein said smearing component extraction means extracts a smearing component caused by a light beam having a wavelength within a received photosensitive range in said imaging means for carrying out photo-electric conversion.

9. An image processing apparatus for an endoscope according to claim 5, wherein said imaging means has a plurality of pixels disposed on an imaging surface and transfers signals subjected to photo-electric conversion for said plurality of pixels to an output unit;

and

said smearing component extraction means uses luminance information obtained from a plurality of pixels disposed along directions in which signals to be output are transferred, said signals having been subjected to said photo-electric conversion by said imaging means so that said smearing component extraction means determines correlation values indicating whether or not said luminance information obtained from the plurality of said pixels disposed along said transfer directions has a value uniformly equal to or greater than a predetermined luminance level in said respective transfer directions and extracts a high luminance portion showing a high correlation value as a smearing component.

10. An image processing apparatus for an endoscope according to claim 5, wherein said correction means consists of a subtraction means for subtracting a smearing component output from said smearing component extraction means from an original image composed of an electric signal output from said imaging means.

11. An image processing apparatus for an endoscope according to claim 5, wherein said imaging means includes a plurality of pixels disposed on an imaging surface and transfers signals having been subjected to photo-electric conversion for said plurality of pixels to an output unit;

and

said smearing component extraction means includes correlation calculation means for determining predetermined correlation functions in directions in which smearing occurs in said imaging means from an original image composed of an electric signal output from said imaging means and removing a component having said correlation functions of a small value in the directions in which smearing occurs and smearing component detection means for detecting, as said smearing component, values equal to or greater than a predetermined luminance level from an image from which a relevant component is removed by said correlation calculation means.

12. An image processing apparatus for an endoscope according to claim 11, wherein said correlation calculation means removes a component caused by a high luminance light beam, which is out of an object and does not cause smearing, of said high luminance light beams by calculating values of said correlation functions.

13. An image processing apparatus for an endoscope according to claim 11, wherein said correlation calculation means uses luminance information obtained from a plurality of pixels disposed along directions in which signals to be output are transferred, said signals having been subjected to said photo-electric conversion by said imaging means so that said correlation calculation means determines a correlation indicating whether values equal to or greater than a predetermined luminance level substantially uniformly appear or not in said respective transfer directions in said luminance information and outputs a result of the correlation to said smearing component detection means as a component from which the component caused by the light beam out of the object is removed.

14. An image processing apparatus for an endoscope according to claim 11, wherein said smearing component extraction means includes waveform shaping means for shaping the waveform of an output from said smearing component detection means so that the waveform becomes substantially the same as that of the smearing component in an original image and supplies an output from said waveform shaping means to said correction means as said smearing component.

15. An image processing apparatus for an endoscope according to claim 11, wherein said correlation calculation means consists of an average value calculation means for determining average values in a frame or field unit from respective values of information obtained from a plurality of pixels disposed along respective transfer directions in which signals to be output, which have been subjected to said photo-electric conversion by said imaging means are transferred;

and

said smearing component detection means detects, as said smearing component, values equal to or greater than a predetermined luminance level from average values in said respective transfer directions determined by said average value calculation means.

16. An image processing apparatus for an endoscope according to claim 11, wherein said imaging means is arranged to dispose a plurality of pixels flat in a horizontal scan direction and a vertical scan direction and to transfer signals, which have been subjected to photo-electric conversion for said respective pixels, to an output unit;

said correlation calculation means includes addition means, memory means and average value calculation means;

said addition means cumulatively adds the information of pixels which are disposed in a horizontal scan direction, said information being successively supplied from said imaging means and the information stored in said memory means;

said memory means stores values obtained by successively and cumulatively adding information from said pixels disposed at the respective same positions in said horizontal scan direction; and

said average value calculation means divides said cumulated values at the respective same positions in said horizontal scan direction which have been added by said addition means, by the number of horizontal scan lines.

17. An image processing apparatus for an endoscope according to claim 12, wherein said correlation calculation means removes a halation component caused by an illumination light beam irradiated to a subject to be imaged by said imaging means as a component caused by a high luminance light which is out of an object.

18. An image processing apparatus for an endoscope according to claim 14, wherein said waveform shaping means performs waveform shaping according to a high luminance light beam to be irradiated out of a plurality of specific high luminance light beams and shapes the waveform of said high luminance light beam so that the waveform thereof becomes substantially the same as that of a smearing component in an original image caused by said high luminance light beam.

19. An image processing apparatus for an endoscope comprising:

smearing component extraction means for extracting a smearing component caused by a specific high luminance light beam from an original image composed of an electric signal output from imaging means for receiving a light beam and subjecting said received light beam to photo-electric conversion, wherein said smearing component extraction means determines average values of luminance information in respective transfer directions and extracts a portion where said average values are equal to or greater than a predetermined value as a smearing component; and

correction means for correcting said electric signal output from said imaging means by use of said smearing component extracted by said smearing component extraction means.

21. An image processing apparatus for an endoscope according to claim 19 or claim 20, wherein said smearing component extraction means extracts at least one of a smearing component caused by a laser beam as said specific high luminance light beam and a smearing component caused by a guide beam as said specific high luminance light beam indicating a range or a position to which said laser beam is irradiated.

23. An image processing apparatus for an endoscope according to claim 19 or claim 20, wherein said smearing component extraction means extracts a smearing component by changing a criterion for extracting the smearing according to a signal indicating that a light beam having high luminance is irradiated in one or more high luminance light beams of a plurality of specific high luminance light beams.

20. An image processing apparatus for an endoscope comprising:

smearing component extraction means for extracting a smearing component caused by a specific high luminance light beam from an original image composed of an electric signal output from imaging means for receiving a light beam and subjecting said received light beam to photo-electric conversion, wherein said smearing component extraction means determines average values of luminance information in respective transfer directions and extracts a portion where said average values are equal to or greater than a predetermined value as a smearing component;

correction means for correcting said electric signal output from said imaging means by use of said smearing component extracted by said smearing component extraction means; and

control means for controlling whether or not said correction means carries out a correcting operation according to at least one of the condition whether or not said specific high luminance light beam is irradiated and the condition whether or not there is a position where smearing is caused by said specific high luminance light beam in an image composed of an electric signal output from said imaging means.

22. An image processing apparatus for an endoscope according to claim 8 or claim 20, wherein said smearing component extraction means selectively extracts a smearing component caused by at least one light beam of a plurality of specific high luminance light beams under predetermined conditions set according to a signal indicating whether or not at least one light beam of said high luminance light beams is irradiated.

24. An image processing apparatus for an endoscope according to claim 22, wherein said smearing component extraction means selectively extracts a smearing component caused by a laser beam and a smearing component caused by a guide beam according to a signal indicating whether or not the laser beam is irradiated in two specific high luminance light beams including the guide beam which indicates a range or a position to which the laser beam is irradiated and is irradiated at all times and the laser beam which is irradiated only when necessary.

25. An image processing apparatus for an endoscope according to claim 24, wherein when said signal indicates that only a guide beam is irradiated, said smearing component extraction means extracts a smearing component caused by the guide beam by changing a criterion to that according to the guide beam, whereas when said signal indicates that both a guide beam and a laser beam are irradiated, said smearing component extraction means extracts a smearing component caused only by the laser beam by changing the criterion to that according to the laser beam.

26. An image processing apparatus for an endoscope according to claim 20, wherein said control means includes:

determination means for determining whether or not a portion, which is located in an image composed of an electric signal output from said imaging means, simultaneously satisfies two conditions that halation is not caused in said portion by a light beam, which is out of an object and does not cause smearing, of said high luminance light beams and that smearing is caused in said portion by a specific high luminance light beam of said high luminance light beams by comparing an output from said smearing component extraction means with an output from said imaging means; and

correcting operation control means for controlling a correcting operation in said correction means based on a result of determination of said determination means.

27. An image processing apparatus for an endoscope according to claim 26, wherein said imaging means is arranged to dispose a plurality of pixels to a plane shape in a horizontal scan direction and a vertical scan direction and to transfer signals which have been subjected to photo-electric conversion for said plurality of pixels to an output unit;

and

said determination means determines whether not halation but smearing occurs or not by comparing an output from said smearing component extraction means with an output from said imaging means for respective horizontal scan lines, said halation being caused by a light beam, which is out of an object and does not cause smearing, of said high luminance light beams and said smearing being caused by said specific high luminance light.

28. An image processing apparatus for an endoscope according to claim 26, wherein when a result of determination of said determination means satisfies said two conditions, said correcting operation control means permits said correction means to carry out a correcting operation in said portion.

29. An image processing apparatus for an endoscope according to claim 26, wherein when said specific high luminance light beam of said high luminance light beams is irradiated and said two conditions are satisfied as a result of determination of said determination means, said correcting operation control means permits said correction means to carry out a correcting operation in said portion.

30. An image processing apparatus for an endoscope according to claim 20, wherein said control means has discrimination means for changing a selection criterion in correspondence with one high luminance light beam to be irradiated of a plurality of specific high luminance light beams and discriminating between a position where smearing is caused by said one high luminance light beam being irradiated and a position where halation is caused by a light beam, which is out of an object and does not cause smearing, of said high luminance light beams and correcting operation control means for controlling a correction operation in said correction means based on a result of discrimination of said discrimination means.

31. An image processing apparatus for an endoscope, comprising:

smearing component extraction means for extracting a smearing component caused by a high luminance light beam from an original image composed of an image signal of a subject to be imaged, wherein said smearing component extraction means takes predetermined correlations with respect to luminance information in respective directions in which smearing occurs in the original image composed of said image signal, said smearing component extraction means removing components having a small correlation value in said directions and a luminance value equal to or greater than a predetermined value, said smearing component extraction means then detecting a smearing component by extracting a portion where a high correlation value is exhibited, thereby producing said smearing component of an image signal output from imaging means which receives a light beam from a subject and subjects the light beam to photo-electric conversion or a smearing component of an image signal output from image record/reproduction means for recording an output from said imaging means; and

correction means for correcting said original image composed of said image signal by use of the signal of said smearing component extracted by said smearing component extraction means.