Image processing is any form of information procesing for which the input is an image

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Image processing is any form of information processing for which the input is an image, such as photographs or frames of video; the output is not necessarily an image, but can be for instance a set of features of the image. Most image-processing techniques involve treating the image as a two-dimensional signal and applying standard signal processing techniques to it.
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 Image processing is enhancing an image or extracting information or features from an image .
A technique in which the data from an image are digitized and various mathematical operations are applied to the data, generally with a digital computer, in order to create an enhanced image that is more useful or pleasing to a human observer, or to perform some of the interpretation and recognition tasks usually performed by humans. Also known as picture processing.
Image processing is in many cases concerned with taking one array of pixels as input and producing another array of pixels as output which in some way represents an improvement to the original array.
For example, this processing
may remove noise,
improve the contrast of the image,
remove blurring caused by movement of the camera during image acquisition,
it may correct for geometrical distortions caused by the lens
Image processing methods may be broadly divided into
Real space
methods -- which work by directly processing the input pixel array.
Fourier space
methods -- which work by firstly deriving a new representation of the input data by performing a Fourier transform, which is then processed, and finally, an inverse Fourier transform is performed on the resulting data to give the final output image.




APPLICATIONS :
 Photography and printing
 Satellite image processing
 Machine vision
 Medical image processing
 Face detection,feature detection and face identification
 Car barrier detection
• Machine vision (MV) is the application of computer vision to industry and manufacturing. Whereas computer vision is mainly focused on machine-based image processing, machine vision most often requires also digital input/output devices and computer networks to control other manufacturing equipment such as robotic arms
• Medical imaging refers to the techniques and processes used to create images of the human body for clinical purposes or medical science As a discipline and in its widest sense, it is part of biological imaging and incorporates radiology ,radiological sciences, endroscopy , thermography, medical photography and microscopy.
• Face detection is a computer technology that determines the locations and sizes of human faces in arbitrary (digital) images. It detects facial features and ignores anything else, such as buildings, trees and bodies.
• Microscope image processing is a broad term that covers the use of digital image processing techniques to process, analyze and present images obtained from a microscope. Such processing is now commonplace in a number of diverse fields such as medicine , biological research ,cancer research, drug testing, metallurgy, etc .
• Photography is the process of recording pictures by means of capturing light on a light-sensitive medium, such as a film or electronic sensor.
Image processing Services is a sophisticated form of information processing in which both input and output are images like video frames or photos.
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Image processing finds use in many fields such as solving identification problems in forensic medicine, creating weather maps from satellite images etc. The images dealt with are usually those scanned or captured with digital cameras.

Image Processing in the Criminal Justice System
This paper deals with digital image processing in the criminal justice system. The objective is to ensure the successful introduction of forensic imagery as evidence in a court of law. This document includes brief descriptions of advantages, disadvantages, and potential limitations of each major process.
Digital image processing is an accepted practice in forensic science. It is the position of the Scientific Working Group on Imaging Technologies (SWGIT) that any changes to an image made through digital image processing are acceptable in forensic applications provided the following criteria are met:
The original image is preserved
The processing steps are logged when they include techniques other than those used in a traditional photographic darkroom
The end result is presented as an enhanced image, which may be reproduced by applying the logged steps to the original image

This document addresses digital image processing and related legal considerations in the following four categories:
 Image enhancement
 Image restoration
 Image compression
 Image analysis

When using digital image processing techniques, use caution to avoid the introduction of unexplainable artifacts that add misleading information to the image and the loss of image detail that could lead to an erroneous interpretation. Any processing techniques should be applied only to the working image.

The successful introduction of forensic imagery as evidence in a court of law is dependant upon the following four legal tests:
 Reliability
 Reproducibility
 Security
 Discovery

IMAGE PROCESSING

Image enhancement is any process intended to improve the visual appearance of an image. This includes processes that have a direct counterpart in the conventional silver-based photographic laboratory and those that can be accomplished only by using a computer.

Traditional enhancement technique :
Traditional enhancement techniques are techniques that have direct counterparts in traditional darkrooms. They include brightness and contrast adjustment, color balancing, cropping, and dodging and burning. These traditional and acceptable forensic techniques are used to achieve an accurate recording of an event or object.

Brightness adjustment is used when the image is too bright or too dark. If the image is made too bright, there is a risk of loss of detail in light areas. If the image is made too dark, there is a risk of loss of detail in the dark areas.

Color balancing is the adjustment of the color components of an image. The purpose of color balancing is to render the colors in the scene faithfully. Improper color balance adjustment can render colors inaccurately, and objects will appear to have the wrong color when compared to the actual subject.

Contrast adjustment is used when the image lacks sufficient contrast. If the image contrast is increased too much, there is a risk of loss of detail in both light and dark areas.
Cropping is used to remove that portion of the image that is outside the area of interest.
Dodging and burning have the same effect as brightness adjustment but are used in localized areas.
Spotting traditionally has been used to remove artifacts due to dust and scratches on the negatives, but it is not considered to be an acceptable practice on any forensic image.