[[alternative]]A review on the MTF measurement systems for imaging lens modules: taking the measurement methods using various spread function as an example

[[abstract]]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. For example, the effect of diffraction arising from the miniaturization of the optical modules tends to decrease the resolution of the image. 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 compare the advantage and disadvantages of the MTF measurement systems using different spread function methods. In this paper, a theoretical framework is first briefly presented and then, a cost-effective approach is proposed. In this approach, we use pinhole, slit, knife-edge and collimating lens to produce the point, line and edge collimation light sources. Collimated light going through the lens module under test is consecutively detected by the imaging sensor of the proposed system. The images formed by the optical modules are acquired by a computer and then, they are processed by algorithms for computing the MTF. Finally, the advantages and disadvantages of the MTF measurement systems using different spread function methods are presented in this thesis. Key words: modulation transfer function, point-spread function, line-spread function, edge-spread function