Electronics - Inside A Digital Camera

An image sensor is the main building blocks in a digital camera. Figure 1 shows the block diagram of an imaging system.


The scene is focused on the image sensor using the imaging optics. An image sensor comprising a two-dimensional array of pixels converts the light incident at its surface into an array of electrical signals. To perform color imaging, a color-filter-array (CFA) is deposited in a certain pattern on top of the image sensor pixel array. Using such a filter, each pixel produces a signal corresponding to only one of the three colors. The analog pixel data as the electrical signals are read out of the image sensor and digitized by an analog-to-digital converter (ADC).
Further digital signal processing such as white balancing, color correction, diminishing the adverse effects of faulty pixels, imperfect optics etc are done in colour processing section. Finally, the image is compressed and stored in memory. Other processing and control operations are also included for performing auto-focus, auto-exposure, and general camera control.