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Improved edge gradient image clarity evaluation algorithm 会议论文  OAI收割
Wuhan, China, 2023-07-26
作者:  
Shen, Xiangquan;  Xiao, Maosen
  |  收藏  |  浏览/下载:19/0  |  提交时间:2023/12/06
Auto-focus algorithm based on improved SML evaluation function 会议论文  OAI收割
Beijing, China, 2019-07-07
作者:  
Ma, Xiaoyu;  Li, Qiaoling
  |  收藏  |  浏览/下载:22/0  |  提交时间:2020/03/04
Design and analysis of auto-focus assembly for spaceborne remote sensing camera (EI CONFERENCE) 会议论文  OAI收割
2011 International Conference on Electronics, Communications and Control, ICECC 2011, September 9, 2011 - September 11, 2011, Ningbo, China
作者:  
Chen W.;  Gao X.
收藏  |  浏览/下载:33/0  |  提交时间:2013/03/25
Spaceborne remote sensing camera may be out of focus when the environment and photographic distance changes. In order to get higher ground sampled distance for the camera  based on the experience gained from the development of a remote sensing camera  working principle of auto-focus assembly control system was discussed. Time of waveform extraction was reduced. It sets force an auto-focus assembly that uses cam and line guide rail in order to move the lens group. The motion error of the auto-focus assembly was difficult to be eliminated and would affect on the focusing accuracy of the spaceborne remote sensing camera directly. So it was analyzed at both ends of the focusing structure. The CCD detector can keep stable when the remote sensing camera is imaging. The motion error was tested to verify the validity of the simulation result and it is less than 0.01mm. Its accuracy meets using demand. The focusing method of moving focal plane is suitable for spaceborne remote sensing camera. 2011 IEEE.  
Realization of the imaging-auto-focus on the APRC using splicing- CCD (EI CONFERENCE) 会议论文  OAI收割
International Conference on Graphic and Image Processing, ICGIP 2011, October 1, 2011 - October 2, 2011, Cairo, Egypt
Lu Z.; Guo Y.; Xue X.; Ma T.; Lv H.
收藏  |  浏览/下载:23/0  |  提交时间:2013/03/25
Autofocusing technique based on image processing for remote-sensing camera (EI CONFERENCE) 会议论文  OAI收割
International Symposium on Photoelectronic Detection and Imaging 2007 - Image Processing, September 9, 2007 - September 12, 2007, Beijing, China
作者:  
Wang X.;  Xu S.-Y.;  Wang X.;  Wang X.
收藏  |  浏览/下载:25/0  |  提交时间:2013/03/25
The key to the auto-focusing technique based on image processing is the selection of focus measure reflecting image definition. Usually the measures derived are on the premise of the images acquired with the same scene. As for the remote-sensing camera working in linear CCD push-broom imaging mode  the premise doesn't exist because the scenes shot are different at any moment  which brings about difficulties to the selection of the focus measure. To evaluate the image definition  the focus measure based on blur estimation for rough adjustment is proposed to estimate the focused position by only two different lens positions  which greatly saves the auto-focusing time. Another evaluation function based on edge sharpness is developed to find best imaging position in the narrow range. Simulations show that the combination of the two measures has the advantages of rapid reaction and high accuracy.  
Self Imaging technique for refocusing an aerospace camera (EI CONFERENCE) 会议论文  OAI收割
ICO20: Optical Devices and Instruments, August 21, 2005 - August 26, 2005, Changchun, China
作者:  
Li W.;  Li W.;  Wang X.;  Wang X.;  Wang X.
收藏  |  浏览/下载:39/0  |  提交时间:2013/03/25
A novel auto-focusing technique using a self imaging approach is developed for an aerospace camera having large aperture and long focus. Its optical system consists of an emitting system  receiving system  and two penta-prisms. Emitting system has three parts: a light source  beamsplitter  and aim slit. The receiving system includes a field lens  two separate lenses  and CCD. Using two little penta-prisms instead of a large planar mirror makes the autofocus system simple and compact. CCD was used as photoelectric converting device. A defocused signal is acquired by measuring the change of the two slit self-images position imaged on the CCD. A simple and compact construction of the auto-focusing system was proposed. The algorithm to calculate the moving of the slit-self images position was analyzed in order to achieve subpixel position estimation. The results of the experiments show a 10m focusing precision. The system demonstrates high resolution  easy adjustment and high reliability.  
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