2. Understanding digital image - of which it consists Adolf Knoll National Library of the Czech Republic adolf.knoll@nkp.cz © Adolf Knoll, National Library of the Czech Republic

3. Image consists of elements

4. However, some images do not consist of these elements… … as they consist of vectors…

5. Line art as vector graphics or a bitmap? 5 KB as WMF 780 KB as BMP 5 KB as PNG/4bit 11 KB as JPEG (qf 70)

6. How does it function? Analogue to Digital Digital to Analogue Stored digitally encoded information

7. Vector graphics The image can be enhanced without structural disintegration Used for CAD (computer aided design) and in DTP (desk top publishing) Vector editors, e.g. Corel Draw! Vector editors Scalable vector graphics (XML format displayed graphically through software that can decode it)

8. page1.dfltt {font-family:Times New Roman;font-size:14px;font-weight:normal;text- decoration:normal;text-align:left;fill:black;} ; Training Courses Scalable Vector Graphics SVG

10. Raster graphics – bitmaps It consists of picture elements (pixels) created by matrix application of the scanning CCD element Each pixel has its position The image can have max. the same number of pixels as the scanning element If it has more… they are multiplied through recalculation (at cameras e.g. difference between optical and digital zoom)

11. Digital Image Raster graphics (bitmaps) a matrix or eye principle grid of dots BMP, TIFF, GIF,... Vector graphics (line art) a plotting principle combination of various basic graphic objects as lines, ellipses, … Corel Draw! (CDR), AutoCAD (DXF), Encapsulated Postscript (EPS), WMF

12. One Pixel Dimension

13. the pixel has a dimension, but it has no size the number of pixels on a unit of length defines resolution (usually taken as ‘dots per inch’ - dpi) on a flat-bed scanner the resolution of the scanner is applied 1:1 to the scanned original in camera-like devices it can be applied to a smaller or larger area - thus the resolution of the digital image will be higher or lower this fact is a limit for our work One Pixel Dimension

14. Pixel – spatial resolution It is stored in a bitmap, where it has a numbered address (x,y). X y Horizontal resolution Vertical resolution

15. Pixels: their size and dimension

16. Free rotation Rotated 2 degrees right