Tamil Nadu TRB Computer Science Syllabus - Web Scripting - Image Formats

Tamil Nadu TRB Computer Science Syllabus - Web Scripting - Image Formats
Tamil Nadu TRB computer instructors Grade1 exam
-----
Image formats
 Visual presentation of data
Image types
1. Raster / bitmap
a. Uncompressed
b. Compressed
i. Losless
ii. Lossy
2. Vector / line art
Raster Images (JPG / TIFF / PNG / GIF)
 Compiled using pixels or tiny dots, that contains colour and depth
 Resolution dependent (How many of pixels per inch)
 Both determine image quality
 More pixel and Higher resolution is high quality image
 Enlarging a raster image without increase resolution will lose quality (blurry or pixilated)
 Best for web site image
Vector Image (SVG)
 No pixels / resolution, it has points and equation for the lines that connect them (based on algorithm / geometric description)
 Can re-size infinity larger or smaller, without increasing file size
 All fonts, clipart images, charts and graphs in excel / word
 Adobe Illustrator / CorelDRAW are used to created vector images
 Best for logos, animations and text (fonts)
Colour Modes
 RGB
o Red, Green, Blue
o Each pixels contains information about RGB
o Computer monitors / televisions using RGB mode
 CMYK
o Cyan, Magenta, Yellow and Black
o Used in Printers
Image Formats
 TIFF
o Tagged Image File Format
o Extension .tif / .tiff
o No compression and loss less (can be lossy)
o Very high quality image
o Larger file size
o Can have transparency
o Useful for Prints, publications
o Can be 24bit or 48bit for RGB
 BMP
o Bitmap developed by Microsoft for Windows OS
o Extension .bmp
o No compression
o Very high quality
o Larger file size
 JPEG / JPG
o Joint Photographic Experts Group
o Extension .jpeg / .jpg
o Compressed and Lossy format
o Useful for Web, Email
o Editing tools (Photoshop) provide amount of compression while saving.
o 24bit colour (8 for each RGB)
 GIF
o Graphics Interchange Format
o Extension .gif
o Compressed and Lossless (without of loss of quality)
o Can be animated
o Can be transparent
o Limited to only 256 colours (24bit)
o Less in size
o Useful for web
 PNG*
o Portable network Graphics
o Extension .png
o 24bit or 48bit true colour (16million colours)
o Compressed and lossless
o Can have transparency
o Useful for web
 IC*
o ICS – Image Cytometry Standard
o Used in life science Microscopy
o Contains Image data and Microscopic parameters
o Extensions (.ics and .ids)
o .ics a text header file
o .ids image data
o ICS2 using .ics only to have header and image data
o 8 / 16 / 32 bit
 PDF
o Portable Document Format
o Extension .pdf
o Multiplatform document not an image file
 PSD
o PhotoShop Document
o Eternsion .psd
o Image file created by Photoshop
o Contains all imaging options (layers, masks, transparency, text, colour …)
o Can have maximum 30,000 pixels
o Size can be 2GB
 SVG*
o Scalable vector graphics
o Extension .svg
o Developed by World Wide Web Consortium
o XML format

Видео Tamil Nadu TRB Computer Science Syllabus - Web Scripting - Image Formats канала YAAZH SCHOOL யாழ் பள்ளிக்கூடம் : கற்போம் கற்பிப்போம்