This work presents a method to characterize the 2D modulation transfer function (MTF) of electronic imaging systems using a setup that enables single-pixel illumination. The method is based on direct capture of point-spread function (PSF) images; therefore, it allows a higher level of accuracy than methods that derive PSF from multiple line-spread function measurements with a slanted-edge or another macro-target. The work presents a design of a measurement setup for PSF characterization, and a simulation test bench that can be used to simulate PSF. It shows simulated PSF images of 1.1 μm pixel pitch monochrome image sensors with and without μ-lenses, and the 2D-MTF plots that were calculated from these results. It also presents PSF images that were obtained from experimental work with these sensors and the 2D-MTF plots that were calculated for them. 1D-MTF results of the two sensors, as obtained from the slanted edge method, are compared to their cross-section 2D-MTF results, as obtained from PSF measurements. Comparison shows that there is a good agreement between the two methods, specifically, for measurements that are done with green light, and that the 2D-MTF method is more sensitive to spectral variations of the illumination.
Victor Lenchenkov, Orit Skorka, Robert Gravelle, Ulrich Boettiger, Radu Ispasoiu, "Characterization of Image Sensor Resolution by Single-Pixel Illumination" in Proc. IS&T Int’l. Symp. on Electronic Imaging: Image Sensors and Imaging Systems, 2018, pp 459-1 - 459-7, https://doi.org/10.2352/ISSN.2470-1173.2018.11.IMSE-459