Projection system, image processing device, and projection method

An image processing device for performing projection with the use of plurality of projection units, the image processing device comprising:

• a taken image preparation unit configured to prepare a plurality of calibration-use images;
• an extraction unit configured to extract, from each of the plurality of calibration-use images, at least grating points indicating a distortion in a projected image of one of the plurality of projection units and alignment points of the projected image of the one of the plurality of projection units or a projected image of another one of the plurality of projection units;
• a conversion unit configured to convert, onto a common coordinate system, the grating points of the projected images of the plurality of projection units extracted from the plurality of calibration-use images by the extraction unit, based on alignment points common to the plurality of calibration-use images;
• and
• a geometric correction coefficient calculation unit configured to calculate a geometric correction coefficient for providing a projection image to be projected from the plurality of projection units, based on the grating points on the common coordinate system.

A projection method of projecting an image on a projection body by a plurality of projection units, the projection method comprising:

• preparing, by a computer, a plurality of calibration-use images;
• extracting, by the computer, from each of the plurality of calibration-use images, at least grating points indicating a distortion in a projected image of one of the plurality of projection units and alignment points of the projected image of the one of the plurality of projection units or a projected image of another one of the plurality of projection units;
• converting, by the computer, onto a common coordinate system, the grating points of the projected images of the plurality of projection units extracted from the plurality of calibration-use images at the extracting, based on alignment points common to the plurality of calibration-use images;
• and
• calculating, by the computer, a geometric correction coefficient for providing a projection image to be projected from the plurality of projection units, based on the grating points on the common coordinate system converted at the converting.