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Proceedings Paper

Accurate and cost-effective MTF measurement system for lens modules of digital cameras
Author(s): Gao-Wei Chang; Chia-Cheng Liao; Zong-Mu Yeh
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Paper Abstract

For many years, the widening use of digital imaging products, e.g., digital cameras, has given rise to much attention in the market of consumer electronics. However, it is important to measure and enhance the imaging performance of the digital ones, compared to that of conventional cameras (with photographic films). For example, the effect of diffraction arising from the miniaturization of the optical modules tends to decrease the image resolution. As a figure of merit, modulation transfer function (MTF) has been broadly employed to estimate the image quality. Therefore, the objective of this paper is to design and implement an accurate and cost-effective MTF measurement system for the digital camera. Once the MTF of the sensor array is provided, that of the optical module can be then obtained. In this approach, a spatial light modulator (SLM) is employed to modulate the spatial frequency of light emitted from the light-source. The modulated light going through the camera under test is consecutively detected by the sensors. The corresponding images formed from the camera are acquired by a computer and then, they are processed by an algorithm for computing the MTF. Finally, through the investigation on the measurement accuracy from various methods, such as from bar-target and spread-function methods, it appears that our approach gives quite satisfactory results.

Paper Details

Date Published: 29 January 2007
PDF: 12 pages
Proc. SPIE 6494, Image Quality and System Performance IV, 64940S (29 January 2007); doi: 10.1117/12.702678
Show Author Affiliations
Gao-Wei Chang, National Taiwan Normal Univ. (Taiwan)
Chia-Cheng Liao, National Taiwan Normal Univ. (Taiwan)
Zong-Mu Yeh, National Taiwan Normal Univ. (Taiwan)


Published in SPIE Proceedings Vol. 6494:
Image Quality and System Performance IV
Luke C. Cui; Yoichi Miyake, Editor(s)

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