Patent ID: 8736774

Claim:
A projection apparatus comprising: a projection unit configured to project an image onto a target area on a curved surface formed of generatrices of a circular cylinder; an image conversion unit configured to apply geometric transformation to a projected image projected by the projection unit; a parameter acquiring unit configured to acquire a parameter expressing a positional relationship between the projection unit and the curved surface; and a transform function determination unit configured to determine a transform function for use in the geometric transformation based on the parameter, wherein the target area is an area surrounded by: a first line and a second line which are parallel to an axis of the circular cylinder; a third line that is an intersection line of a first plane perpendicular to the axis with the curved surface; and a fourth line that is an intersection line of a second plane parallel to the first plane with the curved surface, and when an image area is such an area that the image applied the geometric transformation is projected onto the curved surface, the parameter includes: a four-corner parameter to match four corners of the image area and four corners of the target area; a first middle point parameter to match a first middle point that is a middle point of a top side of the image area and a middle point of the third line of the target area; a second middle point parameter to match a second middle point that is a middle point of a bottom side of the image area and a middle point of the fourth line of the target area; and a second reference line parameter to, when a line connecting the first middle point to the second middle point of the image area is a first reference line, adjust a position of a second reference line provided between a left side of the image area and the first reference line, or between a right side of the image area and the first reference line.