CMOS IMAGE SENSOR.pptx

CMOS IMAGE SENSOR WHEREAS HOW DIGITAL IMAGE IS SCANNED AND HOW THE COLOUR IMAGE WILL FORMED.

1. Seminar On “CMOS Image Sensor” GOVERNMENT COLLEGE OF ENGINEERING JALGAON (An Autonomous Institute of Government of Maharashtra ) Department Of Electronics and Tele - Communication Engineering (2022-2023) Presented By Lokesh Dhanraj More(1912217) Under the Guidance of Dr. S P Mohani

2. What is a Sensor? PHYSICAL PHENOMENON SENSOR SYSTEM MEASUREMENT OUTPUT A sensor is a device that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument. For example, a thermocouple converts temperature to an output voltage which can be read by a voltmeter. For accuracy, all sensors need to be calibrated against known standards

3. What is an Image Sensor? An image sensor is a device that converts an optical image into an electrical signal. Unlike traditional camera, that use film to capture and store an image, digital cameras use solid-state device called image sensor . Image sensors contain millions of photosensitive diodes known as photo sites. When you take a picture, the camera's shutter opens briefly and each photo site on the image sensor records the brightness of the light that falls on it by accumulating photons. The more light that hits a photo site, the more photons it records.

4. Types of Image Sensors CCD: Charged Coupled Device CMOS: Complementary Metal Oxide Semiconductor

5. Cha r ged Coupl e d Device (CCD) Charge-coupled devices ( CCDs ) are silicon-based integrated circuits consisting of a dense matrix of photodiodes that operate by converting light energy in the form of photons into an electronic charge.

6. Basic Operation of a CCD

7. Types of CCD Image Sensors 1. Interline Transfer CCD Image Sensor 2. Frame Transfer CCD Image Sensor

8. Com p lementary M etal O xide Semi c ond uctor (CMOS) “CMOS" refers to both a particular style of digital circuitry design, and the family of processes used to implement that circuitry on integrated circuits (chips). CMOS circuitry dissipates less power when static, and is denser than other implementations having the same functionality. CMOS circuits use a combination of p- type and n-type metal–oxide– semiconductor field-effect transistors (MOSFETs) to implement logic gates and other digital circuits found in computers, telecommunications equipment, etc.

9. The CMOS approach is more flexible because each pixel can be read individually. In a CMOS sensor, each pixel has its own charge-to-voltage conversion, and the sensor often also includes amplifiers, noise- correction, and digitization circuits, so that the chip outputs digital bits. With each pixel doing its own conversion, uniformity is lower. As shown above, the CMOS image sensor consists of a large pixel matrix that takes care of the registration of incoming light. The electrical voltages that this matrix produces are buffered by column-amplifiers and sent to the on-chip ADC. Basic Operation of CMOS

10. 1. Active Pixel Image Sensor 2. Passive Pixel Image Sensor Types of CMOS Image Sensors

11. Sensing Color

12. CCD vs CMOS Many separate chips required for CCD where cmos is built on single chip . I mage stabilization and I mage compression much more than ccd . Not only does this make the camera smaller, lighter, and cheaper; it also requires less power so batteries last longer. CMOS image sensors can switch modes on the fly between still photography and video. CMOS sensors excel in the capture of outdoor pictures on sunny days, they suffer in low light conditions.

13. Application of Image Sensor

14. Conclusion CMOS imagers will replace CCD devices in some cases, because of its low cost, low power consumption, integration capability, etc. Nevertheless, CCD technology will continue as predominant in high performance systems, such as medical imaging, astronomy, low-end professional cameras, etc. because of its better image quality. To sum up, State-of-the-art of CMOS image sensors has been provided.