IT 523 Digital Image Processing Prof Asim Banerjee
IT 523 Digital Image Processing Prof. Asim Banerjee Lecture 4 7 th August 2007 IT 523 - Digital Image Processing
Elements of DIP System IT 523 - Digital Image Processing (1/3) 2
Elements of DIP System (2/3) • Image acquisition – Scanners, video camera, CCD cameras, digitizers, etc. • Storage – Short term storage, on-line storage and archival storage • Processing – Small personal computers to dedicated processing hardware. IT 523 - Digital Image Processing 3
Elements of DIP System (3/3) • Communication – Local communication between the processing systems – Remote communication for transmission of images • Display – Monochrome Monitors to sophisticated display devices IT 523 - Digital Image Processing 4
Image Sensing & Acquisition • The images of interest are generated by the combination of (1/4) those – An illumination source and – And the reflection or absorption of the energy from that source by the elements of the scene being imaged. • The principal arrangements detectors or sensors are: of the – Single imaging sensor – Line sensor – Array sensor. IT 523 - Digital Image Processing 5
Image Sensing & Acquisition (2/4) IT 523 - Digital Image Processing 6
Image Sensing & Acquisition (3/4) IT 523 - Digital Image Processing 7
Image Sensing & Acquisition (4/4) • Two elements are required to acquire a digital image – A physical device that is sensitive to a band in the electromagnetic spectrum (X-ray, Ultra Violet, Visible, Infrared) to produce an electrical signal proportional to the level of energy sensed (i. e. sensors or detectors) – A digitizer to convert this signal into digital form. NOTE: There are sensors available that directly give digital output. IT 523 - Digital Image Processing 8
Preprocessing • It improves the image in ways that increase the chances of success for the other processes • For example – Enhancing contrast – Removing noise – Isolating regions of interest (ROI). IT 523 - Digital Image Processing 9
Segmentation • It partitions an input image into its constituent parts or objects. NOTE: 1. Autonomous segmentation is one of the most difficult tasks in digital image processing. 2. Good segmentation ensures ease in achieving successful solution to an imaging problem. 3. Bad segmentation guarantee eventual failure to an imaging problem. IT 523 - Digital Image Processing 10
Representation & Description • Representation implies conversion of the data to a form suitable for computer processing e. g. boundary representation or complete region representation. • Description (or feature selection) deals with extracting features that result in some quantitative information of interest or features that can differentiate one class of objects from another. IT 523 - Digital Image Processing 11
Recognition & Interpretation • Recognition implies assigning of a label to an object based on information provided by its descriptors • Interpretation implies assigning of a meaning to an ensemble of recognized objects. IT 523 - Digital Image Processing 12
Image Knowledgebase • The knowledgebase stores the prior knowledge about the outside world (the problem domain) • The processing modules interact with the knowledgebase to aid in the processing. IT 523 - Digital Image Processing 13
That’s all for now. IT 523 - Digital Image Processing 14
- Slides: 14