Consumer imaging I: Processing pipeline, focus, and exposure

Digital photography completely supplanted film photography, with a huge, disruptive shift occurring during the first decade of the twenty-first century. The collapse of film photography led to the fall of industry giant like Kodak. Then in 2007, Apple introduced the smartphone and digital photography went mobile. Today smartphones dominate everyday imaging, but the digital camera industry has survived. In this chapter, we will take a look at the state of the art in consumer digital imaging as it stands halfway through this second decade of the twenty-first century. We follow an image from the photons striking the CMOS electronic sensor through to the compressed image or video stored on a memory card. Starting with a look at the basics of digital photography, we move on to explore the complexity of the image processing pipeline (IPP) that is used on today’s cameras. The reader will be introduced to different color spaces and how these are used for different purposes inside the IPP. The mechanisms of autofocus (AF) and exposure using CMOS sensors are explained, and the concepts of the rolling shutter and high-dynamic-range (HDR) imaging are explained. Video preview and image compression are also explored. In a companion article, we will take a look at some developments in “smart imaging” that allow pictures to be enhanced in ways that mimic high-end photography equipment on miniature smartphone cameras.