Image sensors play an important role both in everyday life and in highly specialized tasks. Image sensors are used in webcams, cell phones, and digital cameras. As shown in Figure 4.1, their application can be confined to tasks such as low-powered miniaturized sensors, high-resolution imagers, high-speed acquisition systems, and machine vision processing. Each application requires certain specifications and characteristics of the image sensor. For example, in one instance, the power consumption can be the dominant factor, while in another application the sensor speed is critical. In portable devices such as mobile phones, low power consumption is preferred . High-speed machine vision task used in industrial plants for food grain separation based on the grain size is an example where high-speed imagers with possible in-pixel processing are appropriate .