CSC 381481 Quarter Fall 0304 Daniela Stan Raicu

CSC 381/481 Quarter: Fall 03/04 Daniela Stan Raicu Email: draicu@cs. depaul. edu Homepage: http: //facweb. cs. depaul. edu/dstan School of CTI, De. Paul University 9/25/2020 Daniela Stan - CSC 381/481 1

Outline Ø Class overview Ø Introduction to Image Processing Ø Main Concepts Ø Applications Ø Getting started with Matlab 9/25/2020 Daniela Stan - CSC 381/481 2

Class Overview Syllabus: Ø Summary of the course Ø Textbook Ø Prerequisites Ø Grading Ø Software Ø Homework/Programming Assignments and Final Project Ø School Policies Office hours: Tuesday, 4: 45 pm-5: 45 pm Thursday, 3: 30 pm-4: 00 pm Office location: CTI #471, Loop campus 9/25/2020 Daniela Stan - CSC 381/481 3

What is a Digital Image? A digital image is a computer representation of a photograph. It consists of a two-dimensional array of integer numbers. The numbers are always positive because they represent the variations in the brightness (reflected light energy) in the corresponding photograph. Each element of the two-dimensional array representing a digital image is called pixel – a short form for picture elements. a(1, 4)=110 (the pixel at coordinates row=1 and column=4 has the integer value=110). The process of representing the value of the pixel is called Quantization. Sampling/ Digitization a(x, y), x=#of rows, y=#of columns 9/25/2020 Daniela Stan - CSC 381/481 4

What is a Digital Image? (cont. ) Low-level interpretation: a digital image is an array of pixel values with no meaning. High-level interpretation: ‘an image is worth a thousand of words’. The challenge of extracting meaningful patterns from such data sets (array of pixels) lead to the research and development in the area of multimedia data mining. Ocean Scene Sky Mountains Grass 9/25/2020 Daniela Stan - CSC 381/481 5

What is Digital Image Processing? Digital image processing is nothing but computer-based manipulation of digital images. It can be considered as an analog of photographic darkroom. The input to a digital image processor is an image. The output of a digital image processor is also an image. This distinction is important to remember because many computer systems deal with digital images with different goals. Output: edge blood image Input: Blood Image Edge detection demo under MATLAB >>demo 9/25/2020 Daniela Stan - CSC 381/481 6

What is Digital Image Analysis? Digital image analysis deals with the computation of image properties such as the number of objects, for example the blood cells in a cell image, their image locations, object areas, and other desired properties. Thus, the input to a digital image analyzer consists of an image and the output is comprised of a set of numbers representing certain image properties. Output: labeled steel grain image Input: Steel grain image Region Labeling of steel grains under MATLAB demos >>demo 9/25/2020 Daniela Stan - CSC 381/481 7

What is Computer Vision? Computer vision / machine vision also deals with images. The goal of a computer vision system is to extract geometrical information from images for actions such as locomotion and object manipulation. A computer vision system must have certain digital image processing and analysis capabilities in achieving its goal. Additionally, a vision system has a large knowledge-base pertaining to its domain of operation. The knowledge-base allows the vision system to evaluate various action options and plan the future actions. Tracking people for monitoring shopping Precincts: Video images ---Fig 1. Edge detection---Fig 2 Then, using a model of the major body parts, anyone in the picture can be located. Once a person is located, they can be tracked by predicting and testing the possible movements from a range of legal articulations of the model ---Figs 3 and 4. Then any deviation from the usual paths can raise an alarm. 9/25/2020 Daniela Stan - CSC 381/481 8

What is Computer Graphics? The output of a computer graphic system is also an image. However, a graphic system produces an output image based the geometrical and surface descriptions of a set of objects, lighting sources, and the geometry of an imaginary camera. Computer graphics / image synthesis shares several concepts and techniques with digital image processing and analysis. 9/25/2020 Daniela Stan - CSC 381/481 9

What is Visual Computing? Visual computing is an emerging field of study arising due to the confluence of : l computer graphics l l digital image processing and analysis l l Creating artificial images and videos from scratch Analysis of images and videos of the real world computer vision Therefore, it deals with synthesis, processing, transformation, and indexing of digital images and videos. 9/25/2020 Daniela Stan - CSC 381/481 10

Why is Visual Computing hot? Applications Market Medical imaging l The global market is worth in excess of £ 1 billion and is growing at about seven per cent per year. l Example: Planning Radiation Therapy When planning radiation therapy of brain tumors from MR scans of the head, it is necessary to apply to most effective dose of radiation to the tumor, yet cause least damage to the surrounding tissue. One approach is for the clinician to select a point within an area of interest, such as the tumour. The system then locates the surrounding points which possess similar characteristics, within a given range of variability. This is repeated for other regions, and other images, to produce a 3 D model. Given this model, an optimal treatment plan can be generated. 9/25/2020 Daniela Stan - CSC 381/481 11

Why is Visual Computing hot? (cont. ) Applications Market Industrial Applications l Industrial inspection l l Fruit grading Inspecting machined parts Remote Sensing and Space Applications l l l Land management Crop classification Surveying by satellite Military Applications l l Recognition of enemy aircraft from radar screens identification of targets from satellite photographs 9/25/2020 Daniela Stan - CSC 381/481 12

More on visual computing Seeing is Believing: Computer Vision and Artificial Intelligence, by Christopher O. Jaynes, http: //www. acm. org/crossroads/xrds 31/vision. html Good places to start reading about computer vision and artificial intelligence: http: //www. aaai. org/AITopics/html/vision. html Applications of computer vision and careers in computer vision: http: //www. bmva. ac. uk/apps/index. html Glossary: http: //www. imagelabs. com/gl. php 9/25/2020 Daniela Stan - CSC 381/481 13

Getting started with Matlab: Ø Matrix algebra laboratory Ø A technical computing environment for high performance numeric computation and visualization. Ø Matlab also features a family of application-specific solutions called toolboxes. Toolboxes are comprehensive collections of Matlab functions (M-files) that extend its environment in order to solve particular classes of problems. Example of toolboxes: - Image Processing - Signal Processing - Neural Networks - Statistics, etc 9/25/2020 Daniela Stan - CSC 381/481 14

Getting started with Matlab Usage: Ø In order to start Matlab, simply type % matlab Ø If you are using a workstation with X capabilities, just start matlab from a console or shell of the workstation you are using; Matlab will notice that you are on a workstation and should open a graphics window. Ø MATLAB and the Image Processing Toolbox are installed in the CTI Software Development (SD) lab (on the sixth floor of the CTI building) Ø Matlab 6. 5 Student version release 13 http: //www. mathworks. com/products/education/student_version/sc/index. shtml 9/25/2020 Daniela Stan - CSC 381/481 15

Getting started with Matlab Documentation: Ø built-in help Matlab’s “help” command to access its built-in help Ø Matlab’s “lookfor” command to access its built-in help Ø hardcopy manuals Ø on-line Matlab reference documentation using a WWW document viewer; this is fully indexed, contains color graphics, and includes hypertext links between related topics. Ø Ø Matlab’s “doc” to start the www document viewer 9/25/2020 Daniela Stan - CSC 381/481 16

Getting started with Matlab Documentation (cont. ) Ø Image processing toolbox documentation: http: //www. mathworks. com/access/helpdesk/help/toolbox/images. shtml Ø Matlab Primer: The purpose of this Primer is to help you begin to use Matlab; as you read the Primer, freely experiment with examples in order to get hands-on experience. http: //math. ucsd. edu/~driver/21 d-s 99/matlab-primer. html Ø Tutorial code snippets: http: //www-cse. ucsd. edu/~sjb/classes/matlab. intro. html Ø Matlab FAQ: http: //www. mit. edu/~pwb/cssm/ 9/25/2020 Daniela Stan - CSC 381/481 17

Getting started with Matlab Demos: % demos 9/25/2020 Daniela Stan - CSC 381/481 18

Getting started with Matlab Image Processing Matlab Demos: 9/25/2020 Daniela Stan - CSC 381/481 19