Contrast-sensitivity-based evaluation method of a surveillance camera’s visual resolution: improvement from the conventional slanted-edge spatial frequency response method
| Autor: | Po Jung Wong, Wei Chung Chao, Han-Ping D. Shieh, Yi-Pai Huang, Fang-Cheng Lin, Zong Qin |
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| Rok vydání: | 2017 |
| Předmět: |
010302 applied physics
Machine vision business.industry Materials Science (miscellaneous) media_common.quotation_subject 1080p Image processing 01 natural sciences Industrial and Manufacturing Engineering 010309 optics Optics 0103 physical sciences Contrast (vision) Computer vision Contrast ratio Sensitivity (control systems) Spatial frequency Artificial intelligence Business and International Management Optical resolution business Mathematics Remote sensing media_common |
| Zdroj: | Applied Optics. 56:1464 |
| ISSN: | 1539-4522 0003-6935 |
| DOI: | 10.1364/ao.56.001464 |
| Popis: | Visual resolution is an important specification of a surveillance camera, and it is usually quantified by linewidths per picture height (LW/PH). The conventional evaluation method adopts the slanted-edge spatial frequency response (e-SFR) and uses a fixed decision contrast ratio to determine LW/PH. However, this method brings about a considerable error with respect to subjectively judged results because the perceptibility of the human vision system (HVS) varies with spatial frequency. Therefore, in this paper, a systematic calculation method, which combines the contrast sensitivity function characterizing the HVS and e-SFR, is proposed to solve LW/PH. Eight 720P camera modules in day mode, four 720P modules in night mode, and two 1080P modules in day mode are actually adopted. Corresponding to the three modes, mean absolute error between objective and subjective LW/PH are suppressed to as low as 26 (3.6% of 720P), 27 (3.8% of 720P), and 49 (4.5% of 1080P), while those of the conventional method are 68 (9.4% of 720P), 95 (13.2% of 720P), and 118 (10.9% of 1080P). |
| Databáze: | OpenAIRE |
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