Accurate and cost-effective MTF measurement system for lens modules of digital cameras

Gao-Wei Chang; Chia-Cheng Liao; Zong-Mu Yeh

doi:10.1117/12.702678

29 January 2007 Accurate and cost-effective MTF measurement system for lens modules of digital cameras

Gao-Wei Chang, Chia-Cheng Liao, Zong-Mu Yeh

Proceedings Volume 6494, Image Quality and System Performance IV; 64940S (2007) https://doi.org/10.1117/12.702678
Event: Electronic Imaging 2007, 2007, San Jose, CA, United States

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.

Citation Download Citation

Gao-Wei Chang, Chia-Cheng Liao, and Zong-Mu Yeh "Accurate and cost-effective MTF measurement system for lens modules of digital cameras", Proc. SPIE 6494, Image Quality and System Performance IV, 64940S (29 January 2007); https://doi.org/10.1117/12.702678

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