CMOS Color Filters: Technical Aspects of Imaging

This lecture covers the technical aspects of CMOS cameras, focusing on microlenses and color filters. It begins with the introduction of microlenses, which are essential for concentrating light onto individual pixels in digital sensors. The instructor explains the advantages of backside illumination over front-side illumination, highlighting how it improves light collection efficiency by reducing metal wiring interference. The discussion then shifts to color imaging, detailing the use of Bayer filters to capture red, green, and blue light. The instructor emphasizes the importance of filter quality and the potential issues with infrared and UV light interference. The lecture also addresses the challenges of moiré patterns in images and presents solutions such as reduced periodicity filters. Finally, the concept of dynamic range is introduced, explaining how combining images with different exposures can enhance image quality. The modulation transfer function is also discussed, illustrating how it quantifies the resolution and performance of image sensors.