Patent ID: 9459518
Filing Date: 2016-10-04
CPC Classification: G03B,H04N

Claim Text:
1. An image calibration method for a projection apparatus adapted to generate an image on a projection plane, the image calibration method comprising: respectively transmitting N optical pulse signals to N calibration reference points on the projection plane, wherein N is greater than or equal to 2, wherein the N calibration reference points comprise a first calibration reference point, a second calibration reference point, a third calibration reference point, and a fourth calibration reference point that are located at four corners of the projection plane corresponding to the image; respectively transmitting a first optical pulse signal, a second optical pulse signal, a third optical pulse signal, and a fourth optical pulse signal to the first calibration reference point, the second calibration reference point, the third calibration reference point, and the fourth calibration reference point; receiving a first reflected optical pulse signal, a second reflected optical pulse signal, a third reflected optical pulse signal, and a fourth reflected optical pulse signal respectively generated by reflecting the first optical pulse signal, the second optical pulse signal, the third optical pulse signal, and the fourth optical pulse signal; respectively calculating the time intervals between the first to the fourth optical pulse signals and the first to the fourth reflected optical pulse signals to obtain the time differences; and performing an image calibration based on the time differences.