Endoscope apparatus and method for operating endoscope apparatus

• US 10,321,802 B2
• Filed: 07/19/2016
• Issued: 06/18/2019
• Est. Priority Date: 01/22/2014
• Status: Active Grant

• Current Assignee: Olympus Corporation
• Original Assignee: Olympus Corporation
• Inventors: Sasaki, Hiroshi
• Primary Examiner(s): Li, Tracy Y.
• Application Number:
  US15/213,702
• Publication Number:
  US 20160324398A1
• Time in Patent Office: 1,064 Days
• CPC Class Codes: A61B 1/00006 of control signals
• CPC Class Codes: A61B 1/000094 extracting biological structures
• CPC Class Codes: A61B 1/000095 for image enhancement
• CPC Class Codes: A61B 1/00188 with focusing or zooming features
• CPC Class Codes: A61B 1/127 with means for preventing fogging A61B1/253 takes precedence
• CPC Class Codes: G02B 23/243 Objectives for endoscopes
• CPC Class Codes: G02B 23/2446 of the image relay G02B23/26 takes precedence
• CPC Class Codes: G02B 23/2453 of the proximal end
• CPC Class Codes: G02B 23/2469 using optical fibres
• CPC Class Codes: G02B 7/04 with mechanism for focusing or varying magnification
• CPC Class Codes: G02B 7/36 using image sharpness techniques , e.g. image processing techniques for generating autofocus signals image data processing per se G06T; in cameras having a solid state image sensor H04N23/67
• CPC Class Codes: G03B 13/36 Autofocus systems
• CPC Class Codes: G06T 2207/10068 Endoscopic image
• CPC Class Codes: G06T 7/0012 Biomedical image inspection
• 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 23/673 based on contrast or high frequency components of image signals, e.g. hill climbing method
• CPC Class Codes: H04N 23/74 by influencing the scene brightness using illuminating means

Abstract

An endoscope apparatus includes a processor including hardware. The processor implements a focus control process that is implemented by controlling the position of a focus lens included in an optical system that is included in an imaging device, and a mist detection process that detects whether or not mist has occurred. The processor implements the focus control process that stops a focus operation that is performed during the focus control process when the mist detection process has detected that mist has occurred.

Claims

1. An endoscope apparatus comprising:

a processor comprising hardware, wherein the processor is configured to;

start performing a focus operation process comprising controlling a position of a focus lens included in an optical system that is included in an imaging device;

perform a mist detection process that detects, from a captured image captured by the imaging device, whether or not mist that occurs from an object when treatment using a treatment tool is performed within the field of view of the imaging device has occurred; and

stop the focus operation process in response to the mist detection process detecting that the mist has occurred,

wherein the mist detection process performed by the processor comprises;

calculating at least two evaluation values among;

a first evaluation value that is a temporal change in a brightness value of the captured image;

a second evaluation value that is a temporal change in a saturation value of the captured image; and

a third evaluation value that is a temporal change in a contrast value of the captured image,

as mist evaluation values; and

detecting whether or not the mist has occurred based on the mist evaluation values.

2. The endoscope apparatus according to claim 1,

wherein the mist detection process performed by the processor comprises:

detecting;

a maximum value of the first evaluation value;

a minimum value of the second evaluation value; and

a minimum value of the third evaluation value; and

determining that the mist has occurred in response to determining that a first timing at which the maximum value of the first evaluation value has been detected, a second timing at which the minimum value of the second evaluation value has been detected, and a third timing at which the minimum value of the third evaluation value has been detected, coincide with each other.

3. The endoscope apparatus according to claim 1,

wherein the mist detection process performed by the processor comprises determining that the mist has occurred in response to determining that the first evaluation value is larger than a given first threshold value, the second evaluation value is smaller than a given second threshold value, and the third evaluation value is smaller than a given third threshold value.

4. The endoscope apparatus according to claim 1,

wherein the focus operation process performed by the processor comprises calculating a focus evaluation value for evaluating a degree of in-focus during the focus operation based on a component of the captured image within a specific frequency band, and

wherein the mist detection process performed by the processor comprises calculating a mist evaluation value for detecting whether or not the mist has occurred based on a component within a frequency band that is lower than the specific frequency band.

5. The endoscope apparatus according to claim 1,

wherein the processor is configured to perform a light intensity control process comprising controlling intensity of illumination light that is applied to an object that is captured in the captured image by the imaging device, and

wherein the mist detection process performed by processor comprises:

correcting a pixel value of the captured image based on the intensity of the illumination light; and

calculating a mist evaluation value for detecting whether or not the mist has occurred based on the corrected pixel value.

6. The endoscope apparatus according to claim 1,

wherein the focus operation process performed by the processor comprises:

setting a focus evaluation value detection area to the captured image;

image, and

calculating a focus evaluation value for evaluating a degree of in-focus during the focus operation process from the focus evaluation value detection area, and

wherein the mist detection process performed by the processor comprises;

setting a mist detection area that includes the focus evaluation value detection area; and

calculating a mist evaluation value for detecting whether or not the mist has occurred from an image within the mist detection area.

7. The endoscope apparatus according to claim 6,

wherein the focus operation process performed by the processor comprises:

setting a first block area that corresponds to the focus evaluation value detection area, and second to nth block areas (n is a natural number equal to or larger than

     2) situated outside the focus evaluation value detection area to be the mist detection area; and

calculating the mist evaluation value from an image within the first to nth block areas.

8. The endoscope apparatus according to claim 1,

wherein the mist detection process performed by the processor comprises:

setting a plurality of block areas to the captured image to be a mist detection area;

calculating an average brightness value, an average saturation value, and an average contrast value corresponding to each of the plurality of block area; and

determining whether or not the mist has occurred based on the average brightness value, the average saturation value, and the average contrast value.

9. The endoscope apparatus according to claim 8,

wherein the mist detection process performed by the processor comprises:

adding up the average brightness values of the plurality of block areas to calculate a first evaluation value;

adding up the average saturation values of the plurality of block areas to calculate a second evaluation value;

adding up the average contrast values of the plurality of block areas to calculate a third evaluation value; and

detecting whether or not the mist has occurred based on the first evaluation value, the second evaluation value, and the third evaluation value.

10. The endoscope apparatus according to claim 8,

wherein the mist detection process performed by the processor comprises:

calculating;

a maximum value among the average brightness values of the plurality of block areas to be a first evaluation value;

a maximum value among the average saturation values of the plurality of block areas to be a second evaluation value; and

a maximum value among the average contrast values of the plurality of block areas to be a third evaluation value; and

detecting whether or not the mist has occurred based on the first evaluation value, the second evaluation value, and the third evaluation value.

11. The endoscope apparatus according to claim 8,

wherein the mist detection process performed by the processor comprises:

calculating;

a standard deviation of the average brightness values of the plurality of block areas to be a first evaluation value;

a standard deviation of the average saturation values of the plurality of block areas to be a second evaluation value; and

a standard deviation of the average contrast values of the plurality of block areas to be a third evaluation value; and

detecting whether or not the mist has occurred based on the first evaluation value, the second evaluation value, and the third evaluation value.

12. The endoscope apparatus according to claim 1,

wherein the processor is configured to:

determine whether or not the mist that was determined to have occurred has disappeared; and

resume the focus operation process that was stopped in response to determining that the mist has disappeared.

13. The endoscope apparatus according to claim 12,

wherein the processor is configured to:

calculate at least two evaluation values among a first evaluation value, a second evaluation value, and a third evaluation value as mist evaluation values, and

determine whether or not the mist has disappeared based on the at least two evaluation values,

wherein the first evaluation value is a temporal change in a brightness value of another captured image captured by the imaging device,

wherein the second evaluation value is a temporal change in a saturation value of the another captured image, and

wherein the third evaluation value is a temporal change in a contrast value of the another captured image.

14. The endoscope apparatus according to claim 1,

wherein stopping the focus operation process performed by the processor comprises moving the focus lens to a position of the focus lens at a timing that precedes a timing at which the processor, performing the mist detection process, detects that the mist has occurred by a given time.

15. The endoscope apparatus according to claim 1,

wherein the mist detection process performed by the processor comprises detecting whether or not the mist has occurred based on whether or not the treatment tool has been set to an ON state.

16. The endoscope apparatus according to claim 1,

wherein stopping the focus operation process performed the processor comprises moving the focus lens to a position of the focus lens at a timing at which the treatment tool has been set to an ON state.

17. The endoscope apparatus according to claim 15,

wherein stopping the focus operation process performed by the processor comprises moving the focus lens to a position of the focus lens at a timing at which the treatment tool has been set to the ON state.

18. A method for operating an endoscope apparatus comprising:

starting to perform a focus operation process comprising controlling a position of a focus lens included in an optical system that is included in an imaging device;

performing a mist detection process comprising detecting, from a captured image captured by the imaging device, whether or not mist that occurs from an object when treatment using a treatment tool is performed within the field of view of the imaging device has occurred; and

stopping the focus operation process in response to the mist detection process detecting that the mist has occurred,

wherein the mist detection process comprises;

calculating at least two evaluation values among;

a first evaluation value that is a temporal change in a brightness value of the captured image;

a second evaluation value that is a temporal change in a saturation value of the captured image; and

a third evaluation value that is a temporal change in a contrast value of the captured image,

as mist evaluation values; and

detecting whether or not the mist has occurred based on the mist evaluation values.

19. A non-transitory computer-readable storage medium device storing instructions for operating an endoscope apparatus, wherein the instructions cause a computer to at least:

start to perform a focus operation process comprising controlling a position of a focus lens included in an optical system that is included in an imaging device;

perform a mist detection process comprising detecting, from a captured image captured by the imaging device, whether or not mist that occurs from an object when treatment using a treatment tool is performed within the field of view of the imaging device has occurred; and

stopping the focus operation process in response to the mist detection process detecting that the mist has occurred,

wherein the mist detection process comprises;

calculating at least two evaluation values among;

a first evaluation value that is a temporal change in a brightness value of the captured image;

a second evaluation value that is a temporal change in a saturation value of the captured image; and

a third evaluation value that is a temporal change in a contrast value of the captured image,

as mist evaluation values; and

detecting whether or not the mist has occurred based on the mist evaluation values.