Projection method and non-transitory computer-readable storage medium storing a program

A projection method comprising:

• projecting, by a projector, a first image onto a projection target object before projecting a projection image;
• storing a first picked-up image of the projection target object in a state where the first image is projected, picked up by an image pickup device from a first position;
• determining a first correspondence between a projector coordinate system representing a position on an image projected from the projector and a camera coordinate system representing a position on an image picked up by the image pickup device, based on the first picked-up image and the first image;
• projecting, by the projector, a second image onto the projection target object in response to reception of a control signal representing occurrence of a change in a positional relationship between the projector and the projection target object;
• storing a second picked-up image of the projection target object in a state where the second image is projected, picked up by the image pickup device from a second position;
• determining a second correspondence between the projector coordinate system and the camera coordinate system, based on the second picked-up image and the second image;
• storing a third picked-up image of the projection target object picked up by the image pickup device from the first position, before projecting, by the projector, the second image onto the projection target object in response to the reception of the control signal;
• storing a fourth picked-up image of the projection target object picked up by the image pickup device from the second position, after projecting, by the projector, the second image onto the projection target object in response to the reception of the control signal;
• generating correction information representing an amount of correction corresponding to the change in the positional relationship, based on one or a plurality of first feature points in a fifth image acquired by converting the third picked-up image into the projector coordinate system, based on the first correspondence, and one or a plurality of second feature points corresponding to the one or plurality of the first feature points, in a sixth image acquired by converting the fourth picked-up image into the projector coordinate system, based on the second correspondence;
• and
• projecting, by the projector, the projection image that is corrected based on the correction information.

A non-transitory computer-readable storage medium storing a program for making a computer execute a method comprising:

• causing a projector to project a first image onto a projection target object before projecting a projection image;
• causing a storage device to store a first picked-up image of the projection target object in a state where the first image is projected, picked up by an image pickup device;
• determining a first correspondence between a projector coordinate system representing a position on an image projected from the projector and a camera coordinate system representing a position on an image picked up by the image pickup device, based on the first picked-up image and the first image;
• causing the projector to project a second image onto the projection target object in response to reception of a control signal representing occurrence of a change in a positional relationship between the projector and the projection target object;
• causing the storage device to store a second picked-up image of the projection target object in a state where the second image is projected, picked up by the image pickup device;
• determining a second correspondence between the projector coordinate system and the camera coordinate system, based on the second picked-up image and the second image;
• generating correction information representing an amount of correction corresponding to the change in the positional relationship, based on one or a plurality of first feature points in a third image acquired by converting the first picked-up image stored in the storage device into the projector coordinate system, based on the first correspondence, and one or a plurality of second feature points corresponding to the one or plurality of the first feature points, in a fourth image acquired by converting the second picked-up image stored in the storage device into the projector coordinate system, based on the second correspondence;
• and
• causing the projector to project the projection image that is corrected based on the correction information.