Projective transformation matrix determination method, projector, and determination system

A projector comprising:

• a projection lens that projects an image;
• at least one processor executes:
• receiving a change instruction to change a positional relationship among four feature points in a situation in which the projection lens projects a first projection image showing the four feature points onto a first area;
• projecting a second projection image via the projection lens showing the four feature points onto the first area in response to the change instruction, the positional relationship among the four feature points in the second projection image differs from the positional relationship among the four feature points in the first projection image;
• and
• determining a projective transformation matrix based on coordinates of the four feature points in the second projection image and coordinates of the four feature points in a first captured image generated by capturing, with a camera, an image of the first area where the second projection image is projected, the projective transformation matrix associating a projection coordinate system which defining coordinates in a projection image projected by the projection lens with a camera coordinate system defining coordinates in a captured image generated by the camera.

A determination system comprising:

• a projector that projects an image;
• a camera that performs imaging;
• and
• a control apparatus comprising any of a computer, a tablet or a smartphone executes:
• receiving a change instruction to change a positional relationship among four feature points in a situation in which the projector projects a first projection image showing the four feature points onto a first area;
• causing the projector to project a second projection image showing the four feature points onto the first area in response to the change instruction, the positional relationship among the four feature points in the second projection image differs from the positional relationship among the four feature points in the first projection image;
• and
• determining a projective transformation matrix based on coordinates of the four feature points in the second projection image and coordinates of the four feature points in a first captured image generated by capturing, with the camera, an image of the first area where the second projection image is projected, the projective transformation matrix associating a projector coordinate system which defining coordinates in a projection image projected by the projector with a camera coordinate system defining coordinates in a captured image generated by the camera.