CMOS Sensors in Cameras..

CMOS Sensors in Cameras..

Lumia 1020 with its Sensor

Due to the advent of smartphones these days, we get to see smartphones equipped with high quality point and shoot camera modules.

Some of you might have noticed the word "CMOS sensors" while looking at the camera department of a phone.Which draws us to my topic.

A camera is modelled around the basic concept of human eye, which goes like this:
Light reflected from an object goes though the Eye lens and falls on the Retina. This is converted to electrical impulses which is then interpreted properly by the brain.

CMOS sensor

Ok,so considering a smartphone with a camera, we have a lens behind the phone and a processor which works as a human brain. So,what about the Retina?

Yup, that is where CMOS sensor comes into picture. This works as a Retina.

CMOS as you all know stands for Complementary Metal Oxide Semiconductor. CMOS sensor is manufactured as a chip ( like a normal microprocessor chip). So, like a microprocessor it has millions of CMOS transistors inside it.
These transistors work as photo-detectors. So, when light  falls on these transistors electrons are emitted as electrical charges, amplified and sent to the processor. The amount of electrons emitted depends on the strength of light falling on it.
Basically, a group of transistors (Photosites) account for a pixel on screen. so, the colour representation on the pixel depends on the light falling on those transistors.

There is other type of image sensor called CCD (Charge Coupled Device) sensor. Although,CCD produces greater quality images, the lower power consumption and the speed of CMOS sensors accounts for its greater usability.

Size of the sensor matters too!!!
Larger sensors will have more transistor count. So, there are more photosites to receive light.This results in finer quality images and high quality resolution (8MP,12MP,16MP..)at the same time.