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Image Processing

Image processing is a method to convert an image into digital form and perform some operations on it, in order to get an enhanced image or to extract some useful information from it.
IMAGE PROCESSINGCONTENTS 1. What is an image? 2. Introduction 3. Purpose of image processing 4. How it works? 5. Methods of image processing 6. Image processing techniques 7. Applications 8. ConclusionWHAT IS AN IMAGE? An image is an array, or a matrix, of square pixels (picture elements) arranged in columns and rows.INTRODUCTION Image processing is a method to convert an image into digital form and perform some operations on it, in order to get an enhanced image or to extract some useful information from it.Image processing basically includes the following three steps.  Importing the image with optical scanner or by digital photography.  Analyzing and manipulating the image which includes data compression and image enhancement and spotting patterns that are not to human eyes like satellite photographs.  Output is the last stage in which result can be altered image or report that is based on image analysis.PURPOSE OF IMAGE PROCESSING The purpose of image processing is divided into 5 groups. They are: 1. Visualization - Observe the objects that are not visible. 2. Image sharpening and restoration - To create a better image. 3. Image retrieval - Seek for the image of interest. 4. Measurement of pattern – Measures various objects in an image. 5. Image Recognition – Distinguish the objects in an imageHOW IT WORKS? In the above figure, an image has been captured by a camera and has been sent to a digital system to remove all the other details, and just focus on the water drop by zooming it in such a way that the quality of the image remains the same.METHODS OF IMAGE PROCESSING The two types of methods used for Image Processing are:  Analog Image processing  Digital Image Processing. Analog image processing is done on analog signals. It includes processing on two dimensional analog signals. The digital image processing deals with developing a digital system that performs operations on an digital image.Analog image processing  Analog image processing is done on analog signals.  In this type of processing, the images are manipulated by electrical means by varying the electrical signal.  The common example include is the television image.  Analog or visual techniques of image processing can be used for the hard copies like printouts and photographs.Digital image processing  The digital image processing deals with developing a digital system that performs operations on an digital image.  Digital Processing techniques help in manipulation of the digital images by using computers.  To get over such flaws and to get originality of information, it has to undergo various phases of processing.The three general phases that all types of data have to undergo while using digital technique are Pre- processing, enhancement and display, information extraction.IMAGE PROCESSING TECHNIQUES The various Image Processing techniques are: • Image representation • Image preprocessing • Image enhancement • Image restoration • Image analysis • Image reconstruction • Image data compression1. Image Representation An image defined in the "real world" is considered to be a function of two real variables, for example, f(x,y) with f as the amplitude (e.g. brightness) of the image at the real coordinate position (x,y).2. Image Preprocessing It includes:-  Scaling The theme of the technique of magnification is to have a closer view by magnifying or zooming the interested part in the imagery.  Rotation Rotation is used in image mosaic, image registration etc.  Mosaic Mosaic is a process of combining two or more images to form a single large image without radiometric imbalance.3. Image Enhancement Techniques Some of the enhancement techniques are: Contrast Stretching The contrast stretching methods are designed exclusively for frequently encountered situations. Noise Filtering Noise filtering is used to filter the unnecessary information from an image. Histogram modification By modifying the histogram, image characteristics can be modified. One such example is Histogram Equalization.4. Image Restoration Image restoration refers to removal or minimization of degradations in an image. This includes de-blurring of images degraded by the limitations of a sensor or its environment, noise filtering, and correction of geometric distortion or non-linearity due to sensors.5. Image Analysis Image analysis is concerned with making quantitative measurements from an image to produce a description of it. In the simplest form, this task could be reading a label on a grocery item, sorting different parts on an assembly line, or measuring the size and orientation of blood cells in a medical image Image analysis techniques require extraction of certain features that aid in the identification of the object.6. Image Reconstruction Image reconstruction is a special class of image restoration problems where a two- (or higher) dimensional object is reconstructed from several one-dimensional projections. Reconstruction algorithms derive an image of a thin axial slice of the object, giving an inside view otherwise unobtainable without performing extensive surgery. Such techniques are important in medical imaging (CT scanners), astronomy, radar imaging, geological exploration, and nondestructive testing of assemblies7. Image Compression  Compression is a very essential tool for archiving image data, image data transfer on the network etc.  There are various techniques available for lossy and lossless compressions.  One of most popular compression techniques, JPEG uses Discrete Cosine Transformation based compression technique.  Currently wavelet based compression techniques are used for higher compression ratios with minimal loss of data.APPLICATIONS Image Processing is used in various applications such as: • Remote Sensing • Medical Imaging • Non-destructive Evaluation • Forensic Studies • Textiles • Document processing • Graphic arts • Printing Industry CONCLUSION  Images are discrete objects  Pixels are samples  Images have limited resolution  The common steps in image processing are image scanning, storing, enhancing and interpretation.  Image processing usually refers to digital image processing, but optical and analog image processing also are possible.  Image Processing forms core research area within engineering and computer science disciplines tooAny queries? 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