Learn the Ins and Outs of CMOS Image Sensors in Free Video Lectures
A pair of detailed video lectures provide a fascinating insight into the mechanisms of CMOS image sensors — the technology featured in nearly every modern digital camera.
Modern image sensor technology is exceptionally complicated and has a rich history. It is also very interesting for technically inclined photographers who are curious about the physics and engineering behind their favorite digital cameras.
Image Sensors World highlighted a nearly hour-long lecture delivered by Richard Crisp, VP and CTO of Etron Technology America. In the video below, which is a sneak peek of The International Society for Optics and Photonics (SPIE)’s new course taught by Crisp, “CMOS Image Sensors: Technology, Applications, and Camera Design Methodology,” Crisp covers a wide range of topics including the differences between CCD and CMOS image sensors, common sensor architectures (like rolling versus global shutter), frontside versus backside illumination, noise, and more.
The video, despite being just one part of a larger paid lecture course, covers many important topics in the world of digital cameras. Topics like rolling versus global shutter and backside illumination are hot topics in photography, and can often be differentiating factors between competing camera models.
In the comments at Image Sensors World, an anonymous reader suggested that those interested in image sensor technology should check out a lecture from Dr. Albert Theuwissen. The video below, which, like SPIE’s video preview, is criminally under-viewed given the richness of information on offer, also covers the basic technology behind CMOS image sensors, including how they turn analog input (photons) into a digital signal, the backbone achievement foundational to digital photography at large.
As Dr. Theuwissen explains, CMOS image sensors reflect the complex combination of many sciences and technologies. An image sensor is “more than just a combination of a photodiode and a transistor,” the presentation explains; it combines device physics, semiconductor technology, analog circuitry, digital circuitry, and a mixture of these circuitry types. Further, as Dr. Theuwissen says, the person, such as a photographer, who judges the success of an image sensor is extremely strict. Even a tiny bit of noise will be noticed. Further, the success or failure of a camera’s image quality goes far beyond the sensor itself — it requires sophisticated collaboration between sensor engineers, semiconductor fabricators, and image signal processors.
Dr. Theuwissen notes that through continued advancements in CMOS sensor technology, photographers can expect improved light efficiency, higher dynamic range, and more sophisticated pixel-level circuitry — although talented circuit designers are “urgently needed” for that ambition.
Between these two detailed videos, there is plenty for image sensor enthusiasts to nerd out about. While digital sensors are ultimately just one part of a photographer’s overall tool kit, it never hurts to have a better understanding of what’s going on under the hood — or behind the lens, in this case.
Image credits: Featured image courtesy of Nikon
