Image sensor

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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...

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  • Mirror Covering sensor, Mirror xposed sensor opened
  • Image sensor

    1. 1. SEMINARONIMAGE SENSOR
    2. 2. 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
    3. 3. 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.
    4. 4. TYPES OF SENSORS Thermal Energy Sensors Electromagnetic Sensors Mechanical Sensors Chemical Sensors Optical and Radiation Sensors Acoustic Sensors Biological Sensors
    5. 5. 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.
    6. 6. 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.
    7. 7. TYPES OF IMAGE SENSORSAn image sensor is typically of two types:1. Charged Coupled Device (CCD)2. Complementary Metal OxideSemiconductor (CMOS)
    8. 8. 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.
    9. 9. CHARGED COUPLED DEVICE (CCD)
    10. 10. 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.
    11. 11. COMPLEMENTARY METAL OXIDESEMICONDUCTOR (CMOS)
    12. 12. 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.
    13. 13. APPLICATIONOFIMAGE SENSORS
    14. 14.  Digital Cameras
    15. 15. PERSONAL DIGITAL ASSISTANCE(PDA)
    16. 16. CAMCORDERS
    17. 17. TOYS AND ROBOTS
    18. 18. FINGERPRINT SCANNER
    19. 19. SOME OTHERAPPLICATIONSBiometrics.Optical Mouse.Video Conferencing.
    20. 20. 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.

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