High Dynamic Range Image Sensors

High Dynamic Range Image SensorsAbbas El GamalDepartment of Electrical EngineeringStanford UniversityISSCC’021 Motivation Some scenes contain very wide range of illumination with intensitiesvarying over 100dB range or more Biological vision systems and silver halide film can image such highdynamic range scenes with little loss of contrast information Dynamic range of solid-state image sensors varies over wide range:high end CCDs 78dBconsumer grade CCDs66dBconsumer grade CMOS imagers 54dB So, except for high end CCDs, image sensor dynamic range is not highenough to capture high dynamic range scenesISSCC’022 Imaging High Dynamic Range Scene – The problemHDR SceneShort Exposure-time ImageISSCC’02Medium Exposure-time ImageLong Exposure-time Image3 Extending Sensor Dynamic Range Several techniques and architectures have been proposed for extendingimage sensor dynamic range – many questions: What exactly is sensor dynamic range, what does it depend on, and howshould it be quantified (100dB, 12 bits, . . . )? In what sense do these techniques extend dynamic range? How well do they work (e.g., accuracy of capturing scene informationand/ or image quality)? How should their performance be compared?– Are all 100dB sensors equivalent?– Is a 120dB sensor better than a 100dB one?ISSCC’024 Tutorial Objectives To provide quantitative understandin