1 July 2011 Autofocus method using dual aperture and color filters
Author Affiliations +
We propose a new autofocus method for digital cameras based on the separation of color components from the incoming light rays and the measure of their disparity. For separating color components, we place two apertures with the red and blue color filters on them. This enables us to get two monochromatic images that have disparities proportional to the distances of the objects from the camera. We also propose a new measure to find the disparity of these color components because the conventional disparity measures show low accuracy for the pair of different color channel images. The measure is based on the observation that the overlap of images with disparity has many weak gradients, whereas the overlap with no disparity has a small number of strong gradients. One of two images is shifted from left to right, and the measure is computed for each position. Then, the position with the maximum measure is considered as the disparity, and the direction and distance of focus are computed from the estimated disparity and camera parameters. The proposed method is implemented in a commercial compact camera, and it has been demonstrated that the method finds the focus in a wide range of distance and illumination conditions.
© (2011) Society of Photo-Optical Instrumentation Engineers (SPIE)
Kwanghyun Koh, Kwanghyun Koh, Jung Gap Kuk, Jung Gap Kuk, Bora Jin, Bora Jin, Wooseok Choi, Wooseok Choi, Nam Ik Cho, Nam Ik Cho, } "Autofocus method using dual aperture and color filters," Journal of Electronic Imaging 20(3), 033002 (1 July 2011). https://doi.org/10.1117/1.3602213 . Submission:


Discomfort glare measurement
Proceedings of SPIE (August 05 2009)
Automatic calibration of a range camera using motion
Proceedings of SPIE (October 12 1994)
Multispectral image capture using a tunable filter
Proceedings of SPIE (December 20 1999)
Optical systems for high-resolution digital still cameras
Proceedings of SPIE (August 26 1999)

Back to Top