What is a CMOS sensor?
A CMOS sensor is a type of electronic chip that converts photons to electrons for digital processing. It is based on complementary metal oxide semiconductor (CMOS) technology, which is commonly used for many integrated circuits today. CMOS sensors are used in digital cameras, digital video cameras, CCTV cameras, scanners, barcode readers, astronomical telescopes, robotic vision, optical character recognition, satellite photography, radar imaging enhancement, and Internet of Things (IoT) devices.
How do CMOS sensors work?
CMOS sensors contain an array of small cells called photodiodes that capture photons of varying wavelengths and intensity when light hits the chip’s surface. These photodiodes convert captured photons into electrons, surrounded by transistors that amplify the charges and transmit them across the chip through circuitry. The analog-to-digital converter within the chip reads these charges and translates them into binary data for creating the digital image. CMOS sensors are manufactured using similar processes to other CMOS chips like microprocessors and memory modules.
CMOS sensors vs. CCD sensors
CMOS sensors are often compared to charge-coupled device (CCD) sensors, with CMOS sensors being easier and less expensive to manufacture due to their simpler structure. CMOS sensors also offer faster readout times and lower power consumption, as additional functions such as image processing can be incorporated directly into the chip. While CCD sensors historically provided better image quality, advances in CMOS technology have narrowed this gap. For example, Canon has developed a CMOS sensor with improved light collection efficiency, resulting in better image quality and reduced noise. This progress is helping CMOS sensors compete in higher-end digital cameras and other applications.