NDLI: Influence of Defocus on Area Measurements

Content Provider	IEEE Xplore Digital Library
Author	Mande Shen Dejun Li Zhouqiao Wu
Copyright Year	2008
Description	Author affiliation: Coll. of Electron. & Inf. Eng., Wuhan Univ. of Sci. & Eng., Wuhan (Mande Shen; Dejun Li; Zhouqiao Wu)
Abstract	Finding the area of an object from image is an essential problem in many applications of machine vision, but there is usually error in area measurement because of defocus. In this work, influence of defocus on area measurement has been researched experimentally and theoretically. The results of experiment show that the relative error is 31.3% when the object plane deviates 10mm from conjugated plane of image plane. A novel method has been developed to amend this error from defocus, according to the relation between maximal image gradient and defocusing amount. Firstly, the relation between maximal image gradient and defocusing amount is calibrated. Secondly, the maximal gradient of image is calculated. Thirdly, the defocusing amount is deduced. Finally, the area of defocused image is amended according to the defocusing amount. After amendment, the relative error of image area is less than 3.8%, when the defocusing amount is within 10mm.
Starting Page	316
Ending Page	319
File Size	154105
Page Count	4
File Format	PDF
ISBN	9781424435302
DOI	10.1109/KAMW.2008.4810487
Language	English
Publisher	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Publisher Date	2008-12-21
Publisher Place	China
Access Restriction	Subscribed
Rights Holder	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Subject Keyword	Charge coupled devices image gradient Area measurement Optical imaging Educational institutions Image segmentation image area error amendment Machine vision Focusing Apertures defocused image Pixel Lenses
Content Type	Text
Resource Type	Article

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in

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