MMA 113 Pr-Lec-02.pdf.pdf

Graphic Image & Data Representation MMA 113 PR-LEC-02 Graphic Image & Data Representation 1. Bit Map vs. Vector 2. Bit Depth 3. Dithering 4. Image Formats  BITMAP Bitmap (BMP) is an image file format that can be used...

Graphic Image & Data Representation MMA 113 PR-LEC-02 Graphic Image & Data Representation 1. Bit Map vs. Vector 2. Bit Depth 3. Dithering 4. Image Formats  BITMAP Bitmap (BMP) is an image file format that can be used to create and store computer graphics. A bitmap file displays a small dots in a pattern that, when viewed from afar, creates an overall image. A bitmap image is a grid made of rows and columns where a specific cell is given a value that fills it in or leaves it blank, thus creating an image out of the data. BITMAP  VECTOR Some common vector formats are the Encapsulated PostScript file (EPS), Adobe Illustrator File (AI), CorelDraw File (CDR), Drawing Interchange Format (DXF) and Scalable Vector Graphics (SVG). The main advantage of vector graphics is that it is possible to resize (scale up and scale down) without affecting the image quality. On the other hand, some vector image formats are native to a specific application, and opening it in other vector applications can be difficult. BITMAP vs VECTOR  BITMAP VS VECTOR Difference Between Bitmap and Vector Definition The bitmap is a type of graphics that represents a rectangular grid of pixels, viewable via a monitor, paper or another display medium. Vector is a type of graphics defined in terms of 2D points that are connected by lines, curves to form polygons and other shapes.  BITMAP VS VECTOR Difference Between Bitmap and Vector Definition FILE TYPE Moreover,.jpg,.gif,.png,.tiff,.psd are some bitmap file types while.ps,.eps,.svf,.ai,.cdr and.svg are vector file types. RESIZABLE Bitmap images are resolution dependent, so they are not resizable without reducing the picture quality. Vector images are resolution independent, so they are resizable without reducing the picture quality. Hence, this is also an important difference between bitmap and vector.  BITMAP VS VECTOR Difference Between Bitmap and Vector Definition FILE SIZE File size is another difference between bitmap and vector. The file size of a vector image is comparatively less than that of a Bitmap image. Editing Ability Furthermore, it is possible to edit bitmap images to some extent, but not as vector images. On the other hand, it is possible to edit vector images without reducing the quality. Therefore, this is also a difference between bitmap and vector.  BITMAP VS VECTOR Difference Between Bitmap and Vector Definition Applications Besides, the bitmap is suitable for photographs whereas the vector graphics is suitable for logos, icons, clipart, and abstract images.  BIT DEPTH Bit Depth Color information stored in an image. The higher the bit depth, the more colros it can store  BIT DEPTH Monochrome 1-bit image: 2^1=1 gray levels 2-bit image: 2^2=4 gray levels...8-bit image: 2^8=256 gray levels BIT DEPTH  BIT DEPTH 1-bit color: 2^1 = 2 colors 24-bit color: 2-bit color: 2^2 = 4 colors 2^24 = 16,777,216 colors  BIT DEPTH 3-bit color: 2^3 = 8 colors 24-bit color: 4-bit color: 2^4 = 16 colors 2^24 = 16,777,216 colors  BIT DEPTH 5-bit color: 2^5 = 32 colors 24-bit color: 6-bit color: 2^6 = 64 colors 2^24 = 16,777,216 colors  BIT DEPTH 7-bit color: 2^7 = 128 colors 24-bit color: 8-bit color: 2^8 = 256 colors 2^24 = 16,777,216 colors  24-Bit Image Difference Between Bitmap and Vector Definition In a color 24-bit image, each pixel is represented by three bytes, usually representing RGB. This format supports 256 × 256 × 256 possible combined colors, or a total of 16,777,216 possible colors.  24-Bit Image (a): Example of 24-bit color image “forestfire.bmp”. (b, c, d): R, G, and B color channels for this image. 24-bit images contain 3 color channels (Red, Green, & Blue)  24-Bit Image An important point: many 24-bit color images are stored as 32-bit images, with an extra byte of data for each pixel used to store an alpha value representing a special effect information (e.g., transparency). PNG Images are the popular image format used that use 32-bits.  Dithering Dithering is used to calculate patterns of dots such that values from 0 to 255(gray levels) correspond to patterns that are more and more filled at darker pixel values, for printing on a 1-bit printer. Dithering  FILE FORMATS Take note: Raster/Bitmap vs Vector Raster (Bitmap) images - generally refer to photographs, pictures - with great color detail, but can’t enlarge without becoming blurry. MADE OF PIXELS Vector images - generally refer to illustrations, drawings - with ability to enlarge without losing quality.  FILE FORMATS FILE FORMATS Bitmap (.bmp) Developed by Microsoft for Windows. Due to BMP being a proprietary format, it is generally recommended to use TIFF files. Compression: None Best For: High quality scans, archival copies Cons: Large File Size  FILE FORMATS JPEG (.jpg,.jpeg) Joint Photographic Experts Group Compression: Lossy - some file information is compressed or lost Best For: Web Images, Non-Professional Printing, E-Mail, Powerpoint Special Attributes: Can choose amount of compression when saving in image editing programs like Adobe Photoshop or GIMP.  FILE FORMATS TIFF Tagged Image File Format (.tiff,.tif) Compression: Lossless - no compression. Very high- quality images. Best For: High quality prints, professional publications, archival copies Special Attributes: Can save transparencies Cons: Large File Size  FILE FORMATS GIF graphics interchange format -Introduced in 1987 to reduce size of images and short animations Limited to 8-bit (256) color images only, which, while producing acceptable color images, is best suited for images with few distinctive colors (e.g., graphics or drawing).  FILE FORMATS POPULAR FILE FORMATS GIF graphics interchange format Compression: Lossless - compression without loss of quality Best For: Web Images Special Attributes: Can be Animated, Can Save Transparency  FILE FORMATS Compression: Lossless - compression without loss of quality Best For: Web Images Special Attributes: Save Transparency  FILE FORMATS EPS (.eps) An EPS or Encapsulated PostScript file is a common vector file type. EPS files can be opened in many illustration applications such as Adobe Illustrator or CorelDRAW. Compression: None - uses vector information Best For: Vector artwork, illustrations Special Attributes: Saves vector information  FILE FORMATS For Image Editors.PSD Adobe Photoshop.XCF GIMP For Illustration/Vector Art.AI Adobe Illustrator.CDR CorelDraw  FILE FORMATS OTHER FILE FORMATS EXIF (Exchange Image files) – contains metadata for images Compressed EXIF files use the baseline JPEG format. A variety of tags (many more than in TIFF) are available to facilitate higher quality printing, since information about the camera and picture-taking conditions (flash, exposure, light source, white balance, type of scene, etc.) can be stored and used by printers for possible color correction algorithms. The EXIF standard also includes the specification of file format for audio that accompanies digital images. As well, it also supports tags for information Needed for conversion to FlashPix (initially developed by Kodak).  FILE FORMATS OTHER FILE FORMATS Microsoft Windows: WMF Macintosh: PAINT and PICT: 1. PAINT was originally used in the MacPaint program, initially only for 1-bit monochrome images. 2. PICT format is used in MacDraw (a vector-based drawing program) for storing structured graphics. X-Windows: PPM the graphics format for the X Window system. PPM supports 24-bit color bitmaps, and can be manipulated using many public domain graphic editors, e.g., xv. https://guides.lib.umich.edu/c.php?g=282942&p=1885348  FILE FORMATS OTHER FILE FORMATS GRAPHIC ANIMATION FILES FLC is an animation or moving picture file format; it was originally created by Animation Pro. Another format, FLI, is similar to FLC. -from Autodesk Animation GL produces somewhat better-quality moving pictures. GL animations can also usually handle larger le sizes. Many older formats: such as DL or Amiga IFF files, Apple Quicktime files, as well as animated GIF89 files.  FILE FORMATS OTHER FILE FORMATS PS (Postscript) & PDF Postscript is an important language for typesetting, and many high-end printers have a Postscript interpreter built into them. -Vector-based  Video Reference Links Explaining Image File Formats: https://www.youtube.com/watch?v=WblPwVq9KnU Bitmap Images: https://www.youtube.com/watch?v=0KmimFoalTI Ordered Dithering: https://www.youtube.com/watch?v=IviNO7iICTM  Reference Link REFERENCES Links: https://helpx.adobe.com/photoshop/using/bit-depth.html https://www.diyphotography.net/what-does-bit-depth-even-mean-and-does-it-matter/ https://www.lumenera.com/blog/bit-depth https://link.springer.com/referenceworkentry/10.1007/978-0-387-78414- https://guides.lib.umich.edu/c.php?g=282942&p=1885348 Book Fundamentals of Multimedia 2nd Edition by Ze-Nian Li, Mark S. Drew & Jiangchuan Liu