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Image SensorsImage Sensors

ByBy:-Ojasvi Pundir:-Ojasvi PundirEN IIIyearEN IIIyear

Roll No-34Roll No-34

What are image sensors?What are image sensors?

Image sensors are those Hardware which senses the Image and responsible for converting Image color to the charge according to the color. Different color have a different value of charge.Image sensors are responsible for the quality of the picture taken/scanned by a Digital camera or a scanner.

Resolution:-Resolution:-Image resolution is a way Image resolution is a way of expressing how sharp or detailed of expressing how sharp or detailed images are. How much the Image is images are. How much the Image is clear to be seen. clear to be seen.

To photographers, or anyone in To photographers, or anyone in optics, optics, resolutionresolution describes the describes the ability of a device to resolve lines ability of a device to resolve lines such as those found on a test chart.such as those found on a test chart.

Factors defining the quality of image Factors defining the quality of image sensorssensors

►Aspect Ratio:-Aspect Ratio:-

The aspect ratio of a sensor is important The aspect ratio of a sensor is important because it determines the shape and because it determines the shape and proportions of the photographs you proportions of the photographs you create.create.

► color depth:-color depth:-

The number of colors in an image is The number of colors in an image is referred to its color depth, pixel-depth, referred to its color depth, pixel-depth, or bit depth.or bit depth.

RRececycle time:-ycle time:- The delay in the processing and storing The delay in the processing and storing

the capture image is called Recycle time, the capture image is called Recycle time, it can range from a few seconds to half a it can range from a few seconds to half a minute.minute.

RRefresh rateefresh rate :- :-

The first brief delay you experience is The first brief delay you experience is between pressing the shutter button and between pressing the shutter button and actually capturing the image. This delay, actually capturing the image. This delay, called the called the refresh rate.refresh rate.

Types of Image SensorsTypes of Image Sensors

CCD (Charge Couple Devices).CCD (Charge Couple Devices). CMOS (Complementary Metal Oxide CMOS (Complementary Metal Oxide

Semiconductor).Semiconductor). Foveon’s X3 Direct Image Sensors.Foveon’s X3 Direct Image Sensors. X-Ray Based Image Sensors.X-Ray Based Image Sensors.

Working of ccd image sensorsWorking of ccd image sensors The CCD shifts one whole row at a The CCD shifts one whole row at a

time into the readout register. The time into the readout register. The readout register then shifts one pixel readout register then shifts one pixel at a time to the output amplifier.at a time to the output amplifier.

CMOS (Complementary Metal CMOS (Complementary Metal Oxide Semiconductor).Oxide Semiconductor).

CMOS is by far the most common and CMOS is by far the most common and highest yielding chip-making process in the highest yielding chip-making process in the world. world.

CMOS technology are used to make millions CMOS technology are used to make millions of chips for computer processors and of chips for computer processors and memory.memory.

Using this same process and the same Using this same process and the same equipment to manufacturer CMOS image equipment to manufacturer CMOS image sensors cuts costs dramatically because the sensors cuts costs dramatically because the fixed costs of the plant are spread over a fixed costs of the plant are spread over a much larger number of devices.much larger number of devices.

Application of CMOS image sensorsApplication of CMOS image sensors CMOS technology is CMOS technology is used in high Quality used in high Quality Digital Cameras Like Digital Cameras Like Cannon, HP etc.Cannon, HP etc.

The Canon EOS 10D is a The Canon EOS 10D is a high-end digital SLR high-end digital SLR from a major from a major manufacturer that uses manufacturer that uses a CMOS image sensor. a CMOS image sensor. The Canon EOS 1Ds, The Canon EOS 1Ds, used by professionals, used by professionals, also uses a CMOS sensor also uses a CMOS sensor and has 11.1 million and has 11.1 million pixels. pixels.

Foveon’s X3 Direct Image Foveon’s X3 Direct Image Sensors.Sensors.

A direct image sensor is an image A direct image sensor is an image sensor that directly captures red, sensor that directly captures red, green, and blue light at each point in green, and blue light at each point in an image during a single exposurean image during a single exposure

Advantage of Advantage of Foveon’s X3 Foveon’s X3 Image Sensors.Image Sensors.

This means that the Foveon X3 direct This means that the Foveon X3 direct image sensor has a stack of pixels image sensor has a stack of pixels that capture each point in the image, that capture each point in the image, forming the first and only direct forming the first and only direct image sensors.image sensors.

X-RAY image sensorsX-RAY image sensors

The X-Ray Image Sensors uses the flat-The X-Ray Image Sensors uses the flat-panel sensor (or LANMIT*) instead of film, panel sensor (or LANMIT*) instead of film, consists of a two-dimensional array of consists of a two-dimensional array of pixels, which detect the light produced by pixels, which detect the light produced by the fluorescent material, producing an the fluorescent material, producing an electrical signal. electrical signal.

**LANMIT: Large Area New MIS Sensor and TFT

Features of X-RAY image sensorFeatures of X-RAY image sensor

Canon's LANMIT large-area optical Canon's LANMIT large-area optical sensor includes sensor drive, low-sensor includes sensor drive, low-noise technologies and a unique MIS noise technologies and a unique MIS (metal-insulator semiconductor) (metal-insulator semiconductor) structure, built with a gate electrode, structure, built with a gate electrode, silicon-nitride layer, amorphous silicon-nitride layer, amorphous silicon. silicon.

Advantage of X-RAY image sensorAdvantage of X-RAY image sensor

The radiographic image of the object The radiographic image of the object can be seen only after this film is can be seen only after this film is developed. While in case of digital X-developed. While in case of digital X-ray it can be seen on the monitor ray it can be seen on the monitor after 3 second of picking the pictureafter 3 second of picking the picture

Comparison of CCD & XComparison of CCD & X33

X3’s layers are embedded in silicon to take X3’s layers are embedded in silicon to take advantage of the fact that red, green, and advantage of the fact that red, green, and

blue light penetrate silicon to different blue light penetrate silicon to different depths – forming the first and only image depths – forming the first and only image

sensor that captures full color at every point sensor that captures full color at every point in the captured imagein the captured image

A Dramatically Different DesignThe revolutionary design of Foveon X3 direct image sensors features three layers of pixels. The layers are embedded in silicon to take advantage of the fact that red, green, and blue light penetrate silicon to different depths — forming the world's first direct image sensor.

Comparison between X3 & Mosaic Comparison between X3 & Mosaic CaptureCapture

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