Image processing apparatus, image capturing system, image processing method, and recording medium

1. An image processing apparatus, comprising:

circuitry configured to

obtain a first image in a first projection, and a second image in a second projection;

transform at least a part of the first image corresponding to the second image, from the first projection to the second projection, to generate a third image in the second projection;

extract a plurality of feature points, respectively, from the second image and the third image;

determine a corresponding area in the third image that corresponds to the second image, based on the plurality of feature points respectively extracted from the second image and the third image;

transform a plurality of points in the corresponding area of the third image, from the second projection to the first projection, to obtain location information indicating locations of the plurality of points in the first projection in the first image; and

store, in a memory, the location information indicating the locations of the plurality of points in the first projection in the first image, in association with the plurality of points in the second projection in the second image.

2. The image processing apparatus of claim 1 , wherein circuitry is further configured to generate correction information to be used for correcting at least one of a brightness and a color of each one of the plurality of points in the corresponding area in the third image, with respect to a brightness and a color of each one of the plurality of points in the second image.

3. The image processing apparatus of claim 2 ,

wherein the circuitry is further configured to convert a shape of the corresponding area in the third image so as to match a shape of the second image, and

wherein the correction information is generated from the brightness and the color of each one of the plurality of points in the second image, corresponding to each one of the plurality of points in the corresponding area having the converted shape.

4. The image processing apparatus of claim 1 , wherein the plurality of points in the second image correspond to plurality of grids that are obtained by dividing the second image into a plurality of grid areas.

5. The image processing apparatus of claim 1 ,

wherein the part of the first image corresponding to the second image is an area of the first image that contains a target object of the second image and surroundings of the target object of the second image, and

wherein the third image is an image that contains the part of the first image.

6. The image processing apparatus of claim 5 , wherein the circuitry is further configured to extract, from the third image, a rectangular area corresponding to the second image, based on similarity between the plurality of feature points in the second image and the plurality of feature points in the third image.

7. The image processing apparatus of claim 5 , wherein the circuitry is further configured to:

extract a plurality of feature points from the first image, and

determine the part of the first image corresponding to the second image, based on the plurality of features points in the first image and the plurality of feature points in the second image.

8. The image processing apparatus according to claim 1 , wherein the first image is a spherical image and the second image is a planar image.

9. The image processing apparatus according to claim 1 , wherein the first projection is an equirectangular projection, and the second projection is a perspective projection.

10. The image processing apparatus according to claim 1 , wherein the image processing apparatus is at least one of a smart phone, a tablet personal computer, a notebook computer, a desktop computer, and a server computer.

11. An image capturing system, comprising:

the image processing apparatus claim 1 ;

a first image capturing device configured to capture a target object and surroundings of the target object to obtain the first image in the first projection, and transmit the first image in the first projection to the image processing apparatus; and

a second image capturing device configured to capture the target object to obtain the second image in the second projection, and transmit the second image in the second projection to the image processing apparatus.

12. The image capturing system of claim 11 , wherein the first image capturing device is a camera configured to capture the target object to generate a spherical image as the first image.

13. An image processing method, comprising:

obtaining a first image in a first projection, and a second image in a second projection;

transforming at least a part of the first image corresponding to the second image, from the first projection to the second projection, to generate a third image in the second projection;

extracting a plurality of feature points, respectively, from the second image and the third image;

determining a corresponding area in the third image that corresponds to the second image, based on the plurality of feature points respectively extracted from the second image and the third image;

transforming a plurality of points in the corresponding area of the third image, from the second projection to the first projection, to obtain location information indicating locations of the plurality of points in the first projection in the first image; and

storing, in a memory, the location information indicating the locations of the plurality of points in the first projection in the first image, in association with the plurality of points in the second projection in the second image.

14. The image processing method of claim 13 , further comprising:

generating correction information to be used for correcting at least one of a brightness and a color of each one of the plurality of points in the corresponding area in the third image, with respect to a brightness and a color of each one of the plurality of points in the second image.

15. A non-transitory recording medium storing computer-readable code for controlling a computer system to carry out an image processing method, the method comprising:

obtaining a first image in a first projection, and a second image in a second projection;

transforming at least a part of the first image corresponding to the second image, from the first projection to the second projection, to generate a third image in the second projection;

extracting a plurality of feature points, respectively, from the second image and the third image;

determining a corresponding area in the third image that corresponds to the second image, based on the plurality of feature points respectively extracted from the second image and the third image;

transforming a plurality of points in the corresponding area of the third image, from the second projection to the first projection, to obtain location information indicating locations of the plurality of points in the first projection in the first image; and

storing, in a memory, the location information indicating the locations of the plurality of points in the first projection in the first image, in association with the plurality of points in the second projection in the second image.