TY - JOUR
T1 - An image-based calibration technique of spatial domain depth-from-defocus
AU - Park, Soon Yong
PY - 2006/9
Y1 - 2006/9
N2 - Depth-from-defocus (DFD) is useful in 3-D range image acquisition and automatic focusing. However, DFD needs precise calibration of internal camera parameters. Most DFD techniques use well known camera calibration techniques or specially designed vision systems to precisely measure the settings of the lens system of a camera. In this paper, we introduce an image-based defocus calibration technique. Especially we employ the Spatial domain Convolution/Deconvolution Transform Method (STM) which is introduced by Subbarao and Surya [Subbarao, M., Surya, G., 1994. Depth-from-defocus: A spatial domain approach. Internat. J. Comput. Vision 13 (3), 271-294]. STM estimates blur parameters σ1 and σ2 of defocused images obtained at two different lens steps of the camera. In STM, the blur difference between two defocused images is considered to be a constant value which is determined by internal camera parameters. We use the blur level of the defocused images to calibrate blur difference and camera parameters. Calibrated parameters yield consistent results in depth estimation. Experimental results of depth measurement using real objects are presented.
AB - Depth-from-defocus (DFD) is useful in 3-D range image acquisition and automatic focusing. However, DFD needs precise calibration of internal camera parameters. Most DFD techniques use well known camera calibration techniques or specially designed vision systems to precisely measure the settings of the lens system of a camera. In this paper, we introduce an image-based defocus calibration technique. Especially we employ the Spatial domain Convolution/Deconvolution Transform Method (STM) which is introduced by Subbarao and Surya [Subbarao, M., Surya, G., 1994. Depth-from-defocus: A spatial domain approach. Internat. J. Comput. Vision 13 (3), 271-294]. STM estimates blur parameters σ1 and σ2 of defocused images obtained at two different lens steps of the camera. In STM, the blur difference between two defocused images is considered to be a constant value which is determined by internal camera parameters. We use the blur level of the defocused images to calibrate blur difference and camera parameters. Calibrated parameters yield consistent results in depth estimation. Experimental results of depth measurement using real objects are presented.
KW - Depth-from-defocus
KW - Image-based defocus calibration
KW - S-transform
UR - http://www.scopus.com/inward/record.url?scp=33646766472&partnerID=8YFLogxK
U2 - 10.1016/j.patrec.2006.01.003
DO - 10.1016/j.patrec.2006.01.003
M3 - Article
AN - SCOPUS:33646766472
SN - 0167-8655
VL - 27
SP - 1318
EP - 1324
JO - Pattern Recognition Letters
JF - Pattern Recognition Letters
IS - 12
ER -