Kernel-based crosstalk quantification and analysis of a CMOS image sensor

Inter-pixel crosstalk degrades the point spread function (PSF) of a scientific imager which affects quantitative interpretation of scientific image data. Compared to the CCD, crosstalk is larger in the CMOS image sensor. This problem is challenging due to constant downscaling of the CMOS technology and pixel size. In this work, we parametrized the inter-pixel crosstalk and also modeled it as an empirically quantifiable kernel. A CMOS image sensor with 6 μm pixel pitch is measured. Evidently the crosstalk value can change with the PSF centroid position inside a pixel, primarily due to the spatial extent of the beam, which causes some optical generation in the surrounding pixels. We demonstrate a crosstalk measurement method and its spatial variation with respect to the spot position. This sub-pixel scanning is conducted to measure any crosstalk variation with respect to the sub-pixel spot position. Notable asymmetry on the crosstalk value between rows and columns as well as in the four corners of the POI is observed. This variation shows how the signal is shared at the pixel boundaries. Several POIs (Pixel of interest) over the scan region are measured to analyze the crosstalk variations.