Image processing
Transcript: OCR Computing A451 - 4.4 Representing Images Candidates should be able to: Explain the representation of an image as a series of pixels Explain the need for metadata such as height, width and colour depth Discuss the effect of colour depth and resolution on the size of an image file Lesson Plan What do you know? Prezzi, Worksheet Questions Review Finish Digital images are like digital sound recordings – they are ‘samples’ (of light instead of sound) the view is represented by millions of coloured dots called pixels. The higher the density of pixels, the clearer and sharper the image will be. a) Obtaining the edges of an image. 48 219 168 145 49 218 87 94 77 52 108 200 78 798 34 65 -Suitable for fingerprints. What is image processing? What are pixels? • • What is metadata? Can you think of any more? Which image format would be most suitable for a professional photographer? Why? • Why aren’t images in this format on mobile phones? • What is the difference between lossy and lossless file compression -Each pixel is just black or white (one bit per pixel). 2. Render it more suitable for autonomous machine perception. Digital Image Processing for Medical Applications http://hello.processing.org/ c) Removing motion blur from an image. Examples may include: What is a digital image ? -Nuclear medicine -Tomography -Ultrasound How is the resolution of an image measured? What resolution is suitable for a monitor display? Give some examples of image formats. How many bits are used to store the information in each pixel? 1 0 1 1 0 1 0 0 1 1 0 1 1 0 0 2. Greyscale image -Each pixel has a particular color; described by the amount of red, green and blue in it. -Each of the RGB components has a range 0-255, this gives a total of (255^3)= 16, 777, 256 different possible colors in the image. Questions http://www.mathworks.co.uk/products/image/ Picture elements. The small packets of image data that make up the image. Pixels or dots per inch. 72 dpi TIFF, JPEG, GIF, RAW, BMP, PNG. 24. 8 for each of the colours red, green and blue. An information file that is stored with the image. It contains information such as date, geographical coordinates, camera speed and aperture setting. Image processing involves changing the nature of an image in order to either:- a) Enhancing the edges of an image to make it appear sharper. Image Processing Applications Please go to questions 1.Binary image Processing 2 And 3.True color, or RGB image 0 0 55 255 0 55 255 55 55 25 55 55 55 55 55 0 0 0 0 0 A digital image is an array of pixels which are tiny little dots of color you see on your screen, and the smallest possible size any image can get. When an image is stored, the image file contains information on every single pixel in that image. -Each pixel is a shade of grey, from 0 (black) to 255 (white) ((one byte(8 bit) per pixel)). Imaging technology -Suitable for medicine (X-rays). RAW. Uncompressed images and so will contain all of the original image data. Very large file sizes, usually about 50 to 100MB. With lossless compression, the original file can be reconstituted from the compressed data but with lossy compression it cannot. Some of the original data is lost. Examples may include: b) Removing noise from an image. Matlab Image processing Types of digital images:- Medical imaging is the technique and process used to create images of the human body (or parts and function thereof) for clinical purposes (medical procedures seeking to reveal, diagnose or examine disease) or medical science (including the study of normal anatomy and physiology). Thanks for your attention So how? Image Processing Software Picture elements. The small packets of image data that make up the image Please look at the pdf workbook provided