Under Guidance of: Dr. U. P. Singh Presented By: Suryanshu Satapathy CONTENTS This presentation covers: What is a image? What is digital image? What is digital image processing? Key Stages In Digital Image Processing Applications x and y denote the spatial co-ordinates.y)).y) .y) gives the intensity of image at that point. derived from a Latin word imago. The magnitude of f( ) at spatial co-ordinates (x.y)). that has a similar appearance to some subject—usually a physical object or a person. SIMPLE MODEL: Image refers to a two dimensional light intensity function denoted by f(x. The amount of light reflected by the objects in the scene – reflectance component (r(x. such as a two dimensional picture. f(x. . stands for an artifact.WHAT I S AN IMAGE? An image.y) can be characterized by two components The amount of source light being incident on the scene being viewed – illumination component (i(x. y) < ∞ 0 < r(x.y)*r(x.y) can be treated as an MxN array for processing. 1 pixel . f(x.Now.y) < 1 f(x.y) 0 < i(x.y) = i(x. Each element of the array represents the intensity values and can be called as pixel or pel. where M and N are the dimension of the image along X and Y directions. the higher the print quality and the larger the data size of the image (in kilobytes or megabytes) TYPES OF IMAGE: Color Image(R. The higher the resolution.RESOLUTION OF AN IMAGE: the dpi (dots per inch = pixels per inch) of an image. The resolution of a digital image is defined as the number of pixels it contains.Y.B-each 0~255) Intensity (Gray level image)(0~255) Binary Image(0~1) . IMAGE: EXAMPLES Gray level Image Coloured Image Binary Image . W H AT I S A D I G I TAL I M AGE ? Processing of a picture or image by digital computer. But computer processes only digital data. So we need a digital image. Obtaining a digital Image : Continuos Image Sampling and quantization Digital image Digitization of the spatial co-ordinates (x.y) is called image sampling. The amplitude digitization is called gray-level quantization . j D) } The image can now be represented as a matrix of integer values .We usually operate on digital (discrete) images by: Sample the 2D space on a regular grid Quantize each sample (round to nearest integer) If our samples are D apart.j] = Quantize{ f(i D. we can write this as: f[i . Result Of SAMPLING AND QUANTIZATION . W HAT I S D I G I TAL I M AGE PROCESSING? Processing describes the act of taking something through an established and usually routine set of procedures to convert it from one form to another. such as photographs or frames of video. the output of image processing can be either an image or a set of characteristics or parameters related to the image. Image processing is a form of signal processing for which the input is an image. green (2) and blue (3) channels . The following example represents a basic operation of image processing The composite image (4) has been split into red (1). Most image processing techniques involve treating the image as a two-dimensional signal and applying standard signal-processing techniques to it. such as processing milk into cheese. IMAGE PROCESSING An image processing operation typically defines a new image g in terms of an existing image f We can transform either the range of ‘t’: Or the domain of ‘f’: . understanding Visualization To improve image quality for human perception and/or computer interpretation Image Image processing Better image Processing of image data for storage and transmission. detection. recognition. reconstruction Analysis. Image Image processing Compressed Image . Why ? Coding/compression Enhancement. restoration. A TYPICAL DIGITAL IMAGE PROCESSING SEQUENCE Imaging systems object observe Sample and quantize digitize Image Acquisition Digital storage (disk) store Digital computer On-line buffer process Refresh/ store Processing Display output Record Display/Storage / Transmission . KEY STAGES IN DIGITAL IMAGE PROCESSING Image Restoration Image Enhancement Segmentation Image Acquisition Object Recognition Problem Domain Colour Image Processing Image Compression Representation & Description . X-ray… Scene elements can be familiar objects or may be a molecule. (Gray level quantization). buried rock formations. To get a 2-D picture of the scene we can use a camera which contains light sensors. Visible light source illuminates a common everyday 3-D scene. The reflected light from the scene being imaged is focused by the camera lens Light falls on the sensing material (a CCD array) and produces electrical signals proportional to the light intensity An A/D converter converts this signal to a set of discrete numbers. human brain… . For eg. infrared. The illumination may originate from a source of electromagnetic energy such as radar.IMAGE ACQUISITION Images are generated by the combination of an illumination source and the reflection or absorption of energy from that source by the elements of the scene being imaged. magnifying… ORIGINAL IMAGE HIGH PASS FILTERED IMAGE .IMAGE ENHANCEMENT To process an image so that the result is more suitable than the original image for a specific application Accentuate certain image features for subsequent analysis or for image display Contrast enhancement. sharpening. noise filtering. IMAGE RESTORATION A class of methods that aim to remove or reduce the degradations that were incurred while the digital image being obtained. The degradations can occur due to: Sensor noise Blur due to camera misfocus Relative object camera motion Random atmospheric turbulence Original image Distorted image(Random Noise) . By compressing an image we can reduce the memory needed to store the image.IMAGE COMPRESSION The storage requirement for images are high. Involves feature selection/Identification and feature extraction. also reduction in bandwidth SEGMENTATION Partition of an image into its constituent parts or objects. . Reduce the number of bits requires to represent an image. reduce the time required for transmission. A P P L I C ATI O N S( NAM I NG FEW…) A INDUSTRIAL INSPECTION Human operators are expensive. slow and unreliable make machines do the job instead industrial vision systems are used in all kinds of industries 19 . MEDICINE Take slice from MRI scan of canine heart. and find boundaries between types of tissue Image with grey levels representing tissue density Use a suitable filter to highlight edges Original MRI Image of a Dog Heart Edge Detection Image . BIOMETRICS ASTRONOMY . TRAFFIC MONITOR DOCUMENT HANDLING . K N A H T U O Y .