This is the image sensing technology base pwerpoint presentation which highlights the basics of image sensing...
Image sensing is a technology of recognising a image or comparing a image or taking a image...
Mirror Covering sensor, Mirror xposed sensor opened
CONTENTSo What is a Sensor?o Types of Sensorso What is an Image Sensor?o Types of Image Sensorso What is CCD?o What is CMOS?o CCD vs CMOSo Applications of Image Sensorso Conclusion
WHAT IS A SENSOR? A sensor is a device that measures aphysical quantity and converts it into asignal which can be read by an observer or byan instrument. For example, a thermocouple convertstemperature to an output voltage which canbe read by a voltmeter. For accuracy, all sensors need to becalibrated against known standards.
TYPES OF SENSORS Thermal Energy Sensors Electromagnetic Sensors Mechanical Sensors Chemical Sensors Optical and Radiation Sensors Acoustic Sensors Biological Sensors
WHAT IS AN IMAGE SENSOR? Unlike traditional camera, An Image Sensor is a photosensitivedevice that converts light signals into digital signals (colours/RGBdata). It uses film to capture and store an image. Image sensors contain millions of photosensitive diodes known asphotosites. When you take a picture, the cameras shutter opens briefly andeach photo site on the image sensor records the brightness of thelight that falls on it by accumulating photons. The more light thathits a photo site, the more photons it records. The brightness recorded by each photosite is then stored as a setof numbers (digital numbers) that can then be used to set thecolor and brightness of a single pixel on the screen or ink on theprinted page to reconstruct the image.
IMAGE SENSOR HISTORY Before 1960 mainly film photography wasdone and vacuum tubes were being used. From 1960-1975 early research anddevelopment was done in the fields of CCDand CMOS. From 1975-1990 commercialization of CCDtook place. After 1990 re-emergence of CMOS took placeand amorphous Si also came into the picture.
TYPES OF IMAGE SENSORSAn image sensor is typically of two types:1. Charged Coupled Device (CCD)2. Complementary Metal OxideSemiconductor (CMOS)
WHAT IS CCD? Charge-coupled devices (CCDs) are silicon-basedintegrated circuits consisting of a dense matrix ofphotodiodes that operate by converting lightenergy in the form of photons into an electroniccharge. Electrons generated by the interaction of photonswith silicon atoms are stored in a potential welland can subsequently be transferred across thechip through registers and output to anamplifier.
WHAT IS CMOS? “CMOS" refers to both a particular style of digitalcircuitry design, and the family of processes usedto implement that circuitry on integrated circuits(chips). CMOS circuitry dissipates less power whenstatic, and is denser than other implementationshaving the same functionality. CMOS circuits use a combination of p-type and n-type metal–oxide–semiconductor field-effecttransistors (MOSFETs) to implement logic gatesand other digital circuits found in computers,telecommunications equipment, and signalprocessing equipment.
CCD VS CMOS CMOS image sensors can incorporate other circuits on the samechip, eliminating the many separate chips required for a CCD. This also allows additional on-chip features to be added at littleextra cost. These features include image stabilization and imagecompression. 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 stillphotography and video. CMOS sensors excel in the capture of outdoor pictures on sunnydays, they suffer in low light conditions. Their sensitivity to light is decreased because part of eachphotosite is covered with circuitry that filters out noise andperforms other functions. The percentage of a pixel devoted to collecting light is called thepixel’s fill factor. CCDs have a 100% fill factor but CMOS camerashave much less.
SOME OTHERAPPLICATIONSBiometrics.Optical Mouse.Video Conferencing.
CONCLUSION Image sensors are an emergent solution forpractically every automation-focused machine-vision application. New electronic fabrication processes, softwareimplementations, and new application fields willdictate the growth of image-sensor technology inthe future.