Image processing apparatus, endoscope system, image processing method, image processing program, and recording medium
It is an object of the present invention to provide an image processing apparatus, an endoscope system, an image processing method, an image processing program, and a recording medium capable of accurately estimating blood vessel information. An image processing apparatus according to an aspect of the present invention includes: an image acquisition unit that acquires an image of a living body; a blood vessel index value calculation unit that calculates a blood vessel index value of the living body from the acquired image; a blood vessel density calculation unit that calculates a blood vessel density of the living body from the acquired image; a blood vessel index value correction unit that corrects the calculated blood vessel index value according to the calculated blood vessel density; and a blood vessel information estimation unit that estimates blood vessel information of the living body based on the corrected blood vessel index value.
1. An image processing apparatus, comprising
a non-transitory storage medium; and
a processor coupled to the non-transitory storage medium and configured to:
acquire an image of a living body;
calculate a blood vessel index value of the living body from the acquired image;
calculate a blood vessel density of the living body from the acquired image;
correct the calculated blood vessel index value according to the calculated blood vessel density; and
estimate blood vessel information of the living body based on the corrected blood vessel index value, wherein
the non-transitory storage medium is configured to store relationship information indicating a relationship between the blood vessel density and the blood vessel index value,
the processor is further configured to correct the calculated blood vessel index value based on the stored relationship information;
the calculated blood vessel index value is corrected by adding a correction amount, in which the correction amount increases as the blood vessel density increases, and a slope of the correction amount over the blood vessel density decreases as the blood vessel density increases,
the slope of the correction amount over the blood vessel density represents a slope of a variation amount over the blood vessel density.
2. The image processing apparatus according to claim 1 ,
wherein the non-transitory storage medium is further configured to store relationship information corresponding to a range of observation light emitted to the living body,
the processor is further configured to acquire range information indicating the range of the observation light at the time of capturing the image, and
correct the blood vessel index value based on relationship information that is selected from the stored relationship information based on the acquired range information.
3. The image processing apparatus according to claim 1 ,
wherein the processor is further configured to acquire a plurality of images having different ranges of observation light emitted to the living body, and
calculate the blood vessel index value using the plurality of acquired images.
4. The image processing apparatus according to claim 2 ,
wherein the processor is further configured to acquire a plurality of images having different ranges of observation light emitted to the living body, and
calculate the blood vessel index value using the plurality of acquired images.
5. The image processing apparatus according to claim 1 ,
wherein the processor is further configured to select a target blood vessel, for which the blood vessel index value is to be calculated, in the acquired image,
wherein the processor selects the target blood vessel based on a user's instruction input for the acquired image.
6. The image processing apparatus according to claim 2 ,
wherein the processor is further configured to select a target blood vessel, for which the blood vessel index value is to be calculated, in the acquired image.
7. The image processing apparatus according to claim 3 ,
wherein the processor is further configured to select a target blood vessel, for which the blood vessel index value is to be calculated, in the acquired image.
8. The image processing apparatus according to claim 6 ,
wherein the processor selects the target blood vessel based on a user's instruction input for the acquired image.
9. The image processing apparatus according to claim 7 ,
wherein the processor selects the target blood vessel based on a user's instruction input for the acquired image.
10. The image processing apparatus according to claim 1 ,
wherein the blood vessel index value includes at least one of a contrast of a blood vessel of the living body, a brightness value of a blood vessel portion, or color information of a blood vessel portion.
11. The image processing apparatus according to claim 2 ,
wherein the blood vessel index value includes at least one of a contrast of a blood vessel of the living body, a brightness value of a blood vessel portion, or color information of a blood vessel portion.
12. The image processing apparatus according to claim 3 ,
wherein the blood vessel index value includes at least one of a contrast of a blood vessel of the living body, a brightness value of a blood vessel portion, or color information of a blood vessel portion.
13. The image processing apparatus according to claim 4 ,
wherein the blood vessel index value includes at least one of a contrast of a blood vessel of the living body, a brightness value of a blood vessel portion, or color information of a blood vessel portion.
14. The image processing apparatus according to claim 5 ,
wherein the blood vessel index value includes at least one of a contrast of a blood vessel of the living body, a brightness value of a blood vessel portion, or color information of a blood vessel portion.
15. The image processing apparatus according to claim 1 ,
wherein the blood vessel information includes at least one of a depth of a blood vessel of the living body, a thickness of a blood vessel, a blood volume, or an oxygen saturation of a blood vessel.
16. An image processing apparatus, comprising
a non-transitory storage medium; and
a processor coupled to the non-transitory storage medium and configured to:
acquire a plurality of images having different ranges of observation light emitted to the living body and range information indicating the range of the observation light at the time of capturing the plurality of images;
calculate a blood vessel index value of the living body from the acquired images;
calculate a blood vessel density of the living body from the acquired images;
correct the calculated blood vessel index value according to the calculated blood vessel density; and
estimate blood vessel information of the living body based on a corrected blood vessel index value, wherein
the non-transitory storage medium is configured to store relationship information indicating a relationship between the blood vessel density and the blood vessel index value, and store relationship information corresponding to a range of observation light emitted to the living body,
the processor is further configured to correct the blood vessel index value based on relationship information that is selected from the stored relationship information based on the acquired range information, and estimate blood vessel information of the living body based on the corrected blood vessel index value;
the calculated blood vessel index value is corrected by adding a correction amount, in which the correction amount increases as the blood vessel density increases, and a slope of the correction amount over the blood vessel density decreases as the blood vessel density increases,
the slope of the correction amount over the blood vessel density represents a slope of a variation amount over the blood vessel density.
17. An endoscope system, comprising:
a light source that emits observation light to a living body;
an endoscope main body that captures an image of the living body under the emitted observation light; and
the image processing apparatus according to claim 1 ,
wherein the image processing apparatus acquires the image captured by the endoscope main body.
18. An image processing method, comprising:
an image acquisition step of acquiring an image of a living body;
a blood vessel index value calculation step of calculating a blood vessel index value of the living body from the acquired image;
a blood vessel density calculation step of calculating a blood vessel density of the living body from the acquired image;
a blood vessel index value correction step of correcting the calculated blood vessel index value according to the calculated blood vessel density; and
a blood vessel information estimation step of estimating blood vessel information of the living body based on the corrected blood vessel index value, wherein
the calculated blood vessel index value is corrected by adding a correction amount, in which the correction amount increases as the blood vessel density increases, and a slope of the correction amount over the blood vessel density decreases as the blood vessel density increases,
the slope of the correction amount over the blood vessel density represents a slope of a variation amount over the blood vessel density.
19. A non-transitory recording medium on which an executable computer readable code is configured to be executed by an image processing apparatus to perform the image processing method of claim 18 is recorded.