Definition of CMOS image sensor

Photonics Dictionary

CMOS image sensor: A CMOS image sensor, short for complementary metal-oxide-semiconductor image sensor, is a type of semiconductor device used to capture visual information and convert it into electrical signals for digital imaging applications. CMOS image sensors are widely employed in digital cameras, smartphones, webcams, automotive cameras, medical imaging devices, and various other imaging systems.

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Key features and components of a CMOS image sensor include:

Pixel array: A CMOS image sensor consists of an array of individual photosensitive pixels arranged in rows and columns. Each pixel serves as a miniature photosensitive detector that captures light and generates an electrical signal proportional to the intensity of the incident light.

Photodiodes: Each pixel typically contains a photodiode, a semiconductor device that generates charge carriers (electrons and holes) when exposed to light. The number of charge carriers generated is proportional to the intensity of the incident light.

Readout circuitry: CMOS image sensors feature integrated readout circuitry associated with each pixel. This circuitry amplifies, converts, and transfers the generated charge from the photodiode to the sensor's output for further processing.

Signal processing circuitry: In addition to readout circuitry, CMOS image sensors often include on-chip signal processing circuitry for tasks such as analog-to-digital conversion, noise reduction, color interpolation (in color sensors), and other image enhancement functions.

Control electronics: Control electronics manage the overall operation of the CMOS image sensor, including exposure settings, gain control, frame rate control, and communication with external devices.

CMOS image sensors offer several advantages over traditional charge-coupled device (CCD) sensors, including lower power consumption, faster readout speeds, and the potential for integration of additional functionality onto the same chip. These factors contribute to the widespread adoption of CMOS image sensors in various imaging applications.