Digital Image Processing Ch1 : Introduction PDF

Digital Image Processing Ch1 : Introduction By Dr/Safynaz AbdEl-Fattah Sayed Computer Science Department Beni-Suef University  Course Description Introduction Digital Image Fundamentals Intensity Transformations and Spatial Filtering Filtering in the Freq...

Digital Image Processing Ch1 : Introduction By Dr/Safynaz AbdEl-Fattah Sayed Computer Science Department Beni-Suef University  Course Description Introduction Digital Image Fundamentals Intensity Transformations and Spatial Filtering Filtering in the Frequency Domain Image Restoration  Course Textbook “Digital Image Processing”, Rafael C. Gonzalez & Richard E. Woods, Addison- Wesley, 2008.  Chapter Outline (Introduction) What is Digital Image Processing? The Origins of Digital Image Processing. Examples of Fields that Use Digital Image Processing. Fundamental Steps in Digital Image Processing Components of an Image Processing System  What is Digital Image Processing? Digital Image — a two-dimensional function f ( x, y ) x and y are spatial coordinates The amplitude of f is called intensity or gray level at the point (x, y) Digital image processing refers to processing a digital image, where X and Y have finite elements (picture elements) or (pixels). Pixel — the elements of a digital image  Image Processing & Image Analysis &Computer Vision There is no general agreement among authors regarding where image processing stops and other related areas, such as image analysis and computer vision, start. Computer vision is a field of artificial intelligence (AI) that enables computers and systems to derive meaningful information from digital images, videos and other visual inputs. – emulate human vision, including learning and being able to make inferences – take actions or make recommendations based on that information. Digital Image Analysis: concerns the description and recognition of the image contents. ⪢ The image analysis process involves two other topics: o Feature Extraction: is the process of acquiring higher level image information, such as shape or color information. o Pattern Classification: is the act of taking this higher –level information and identifying objects within the image.  Image Processing & Image Analysis &Computer Vision Digital image processing focuses on two major tasks :- Improvement of pictorial information for human interpretation (compression, enhancement, …..). Processing of image data for storage, transmission and representation for autonomous machine perception. Image processing: are Algorithms that alter an input image to create new image  What is Digital Image Processing? There are three levels; from image processing to computer vision. Low Level Process (Image Processing) Input: Image Output: Image Examples: Noise removal, image sharpening Mid Level Process (Image Analysis) Input: Image Output: Attributes Examples: Object recognition, segmentation High Level Process (Computer Vision) Input: Image Output: Understanding Examples: Scene understanding, autonomous navigation  Image processing applications Medical field: image enhancement. Image Deblurring  Image processing applications Handwriting recognition Face detection  Image processing applications Iris recognition Noise Removal  The Origins of Digital Image Processing. 1922: image from Some of the earliest 1921 Telegraphing Photographic produced digital images; image Reproduction Using punched Tape however no DIP digital (5 levels of gray) (15 levels of gray) images; however, no DIP was involved since there was no digital computer at that time. We can see how the quality is poor because of the generation and reproduction mechanisms. The start of the digital computers was in 1940s with VN (di Von Neumann. (read some nice history in the book).  The Origins of Digital Image Processing. First image of the moon to be processed by Digital Computer. In parallel, medical imaging started in 1960s. Many medical imaging techniques started to develop, e.g., Computer Tomography (CT), X-rays. Later, digital images took place in many other applications, e.g., – Geography)‫(علم الجغرافيا‬: Studying pollution patterns by enhancing degraded images. – Archeology(‫)علم االثار‬: restoring, blurred images, – Physics and Cosmology)‫(الفيزياء والكونيات‬: studying galaxies…  Examples of Fields that Use Digital Image Processing Electromagnetic (EM) spectrum are propagating and have the dual nature, waves and particles. We can demonstrate some images from each band. We have to notice that in each application we use the band that it is suitable and capable of displaying the properties of the object. We could have other taxonomies of images than the band, e.g., by transmitting mechanism, by receiving, by technology. We can detect the portion of the wave penetrated the object or that reflected from the object. This depends on both the imaging system and the object.  Gamma-Ray Imaging Major use in: Nuclear medicine (‫)الطب النووي‬: injection of radio active material (rather than external source of radiation) that decays after transmission and received by detector (Fig a,b) See the tumors in brain and lung of Fig. b. Astronomy (‫)علم الفلك‬: Fig. c is a self radiating star that exploded 15,000 ago.  X-Ray Imaging Mainly used in medical imaging, but also used in astronomy )‫ (علم الفلك‬. Emission is produced by heating a cathode and the Industry patient is placed between it and the detector (which Chest is a film). X-ray analog. X-Ray Digital X-ray is produced by either digitizing the analog or directly by having X-ray fall on digital device (e.g., digital mammography). Fig a-b. Angiogram Other X-Ray uses is CT scans, in which the object is ‫أوعية دموية‬ sliced and each slice is imaged, Fig. c Similar uses is for X-Ray exist in industry, e.g., testing Head CT circuits. Fig. d  Ultraviolet Band )‫(االشعة فوق البنفسجية‬ Appear in many applications, e.g., Normal corn Smut corn microscopy, lasers, biological imaging, and astronomical observations.  Imaging in the Visible and Infrared Bands Imaging in visible band is ubiquitous; frequently it is accompanied by infrared imaging. Like the following Examples: Whether observation and Prediction: another application for multispectral imaging from satellites. The images are from light microscopes, but Fig: Satellite image of Hurricane Katrina from different fields.  Imaging in the Visible and Infrared Bands Remote Sensing: is another area of application for visible band; one object is imaged using different bands all in the visible bands, all in the visible range (called thematic bands) in NASA’s LANDSAT satellite. In Fig 1.10, notice the difference between the infrared bands (4-7) and the first three; e.g., the river is so obvious in band 4 and 5.  Imaging in the Visible Bands Automated visual inspection of manufactured goods: Fig. a. the black square is a missing part. Fig. b. no missing pills Fig. c. There is a bottle that is not filled up. Fig. d. unacceptable plastic product because of bubbles. Fig. e. Some burned flakes exist, which degrades the quality. Fig. f. detection of imperfections in lens. Fig. a. Finger print identification. Fig. b. Automatic counting of bills, reading of serial numbers, …etc. Fig. c. automatic plate reading.  Imaging in the Microwave Band Dominant application is radar. Some radar waves penetrate )‫(اخترق‬clouds and vegetation)‫ (النباتات‬which makes it capable of collecting data over any region any time. A flash camera produces microwave pulses, then reflects from the surface of the object to be detected and a snapshot the object to be detected and a snapshot image is taken.  Imaging in the Radio Band This is the other extreme end of the spectrum (as opposed to Gamma Rays). Major application is in medical applications, e.g., Magnetic Resonance Imaging (MRI), and astronomy. The patient is placed in a strong The patient is placed in a strong magnet and radio pulses are passed through his body. Each pulse results in another pulse emitted by the patient tissues. The strength and location is detected by a computer and an image is produced.  Other imaging Modalities Many images in many bands for exactly the same object; totally different images!! Which one of these is the object? The question is wrong, because all of these (and other images in other bands) are the interaction among three things: – 1- the wave hitting the object. – 2- the quality of the object and how it reacts with the wave. – 3- the receiver quality, whether it is the human eye or a special purpose camera.  Examples in which Other imaging Modalities Are used A- Acoustic Imaging ‫التصوير الصوتي‬ Acoustic images in medical applications (specially for imaging unborn babies) use ultrasound (millions of HZ) 1. The ultrasound system (a computer, ultrasound probe consisting of a source, a receiver, and a display) transmits high-frequency (1 to 5 MHz) sound pulses into the body. 2. The sound waves travel into the body and hit a boundary between tissues. Some of the sound waves are reflected back to the probe, while some travel on further until they reach another boundary and are reflected. 3. The reflected waves are picked up by the probe and relayed to the computer. 4. The machine calculates the distance from the probe to the tissue or organ boundaries using the speed of sound in tissue (1540 m/s) and the time of each echo’s return. 5. The system displays the distances and intensities of the echoes on the screen, forming a two- dimensional image.  Examples in which Other imaging Modalities Are used B. Electron Microscopy  Examples in which Other imaging Modalities Are used C. Fractals (Synthesis Images) Here, their neither object nor wave; it is synthesized by computers!!! This is generated according to mathematical model (Fig. a., b.) It can generate beautiful shapes and patterns. Fundamental Steps in Digital Image Processing Fundamental Steps in Digital Image Processing  Fundamental Steps in Digital Image Processing Image Enhancement: taking an image and improving it visually  Fundamental Steps in Digital Image Processing Image Restoration : taking an image with some known or estimated degradation and restoring it to its original appearing.  Fundamental Steps in Digital Image Processing Morphological Processing extracting image component that are useful in the representation and description of region shape, such as boundaries, skeletons, and the convex hull.  Fundamental Steps in Digital Image Processing Segmentation subdivides an image into its constituent. Fundamental Steps in Digital Image Processing Fundamental Steps in Digital Image Processing  Components of an Image Processing The computer can range from a PC to a System supercomputer. Software for image processing consists of specialized modules that perform specific tasks. Mass storage is a must for large image like of size 1024 × 1024 pixels. Image displays in use today are mainly color, flat screen monitors. Hardcopy devices for recording images include laser printers, film cameras, heat- sensitive devices, ink-jet units, and digital units, such as optical and CD-ROM disks. Networking and cloud communication are almost default functions in any computer system in use today.