On extended depth of field to improve the quality of automated thermographic measurements in unknown environments

Focusing is essential for the quality of thermal imaging. But due to physical constraints, only a small distance area around the focal distance, called the depth of field (DOF), appears acceptably sharp in a single thermogram. For scenes containing multiple objects at different distances from the ca...

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Bibliographic Details
Published inQuantitative infrared thermography Vol. 9; no. 2; pp. 135 - 150
Main Author Soldan, Samuel
Format Journal Article
LanguageEnglish
Published Routledge 01.12.2012
Subjects
data compaction
data fusion
extended depth of field
focusing
image processing
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Summary:Focusing is essential for the quality of thermal imaging. But due to physical constraints, only a small distance area around the focal distance, called the depth of field (DOF), appears acceptably sharp in a single thermogram. For scenes containing multiple objects at different distances from the camera or one along the optical axis outstretched object, it is hard to have all parts of the image sharp within one measurement. This is impossible if the distance between the closest and the farthest region is larger than the DOF. This work describes a solution to get an all-in-focus measurement that works by taking a measurement series with different focal settings and combining the sharp parts using digital image processing. Different possibilities for this process are discussed and examples are given.
ISSN:1768-6733
2116-7176
DOI:10.1080/17686733.2012.738110