Understanding Scanner Technology for Digital Data Conversion

1. Scanner www.ustudy.in

2. Scanner Introduction: • Scanner is an input device. • It reads the graphical images or line art or text from the source and converts it into digital information and send it to the computer. www.ustudy.in

3. Scanner www.ustudy.in

4. Cont., • It reads the graphical images or line art or text from the source and converts it into digital information and send it to the computer. • Scanners are used to give large volume of data as input to the computer. www.ustudy.in

5. Types of scanner • Flat bed scanners • Sheet fed scanners • Hand held scanners www.ustudy.in

6. Sheet fed scanners Flat bed scanners Hand held scanners www.ustudy.in

7. Operation • Scanner is operates on the principle of reflection . • That is , when a light source falls on an image document , the incident light reflects. • The reflection depends upon the color and size of the images in the document. www.ustudy.in

8. Structure of Scanner • That is black or white spaces reflect more light than colored or inked letters or images. www.ustudy.in

9. Cont., • The light from the lamp is made to fall on the document through the glass plate. • The head receives the reflected light from the document with the help of mirrors (m). • The reflected light is filtered with the help of R,G,B filters. www.ustudy.in

10. Cont., • The filtered light is made to fall on a light sensor having 1024 elements using a mirror and a lens. • The sensor converts the analog signals into digital signals and is given as output. • The scan head is moved over the document with the help of a motor. www.ustudy.in

11. Cont., • The scan head is move a fraction of an inch at a time. • The minimum size of a document that can be scanned depends up on the size of the window. www.ustudy.in

12. Scan Resolution • The number of dots or pixels per inch a scanner can resoluve for a document. • In other words resolution relates to the fineness or clarity of the image scanned by the scanner. www.ustudy.in

13. Different Resolutions • 200 dpi – Dots Per Inch • 400 dpi • 600 dpi and so on. • The more dots per inch a scanner can resolve, the more clarity the resulting image will have. www.ustudy.in

14. Scan modes • Line art • Half toning • Gray scale • True color www.ustudy.in

15. Line art • This mode scans the image and store it as a binary information I0 ‘s and 1 ‘ s). • In this 1 represent black color and 0 represent white color. • This mode is useful to scan text or line drawings. • Picture do not scan well in this mode. This is used to scan black and white images. www.ustudy.in

16. Half toning • This mode scans the image is such a way that it can be printed by a printer that will not support color printing. www.ustudy.in

17. Gray scale • This mode scans the image and store it as a 256 gray level information. • This is used to scan black and white images. www.ustudy.in

18. True color • This mode scans the image and store it as color components • RED • GREEN • BLUE • This mode is well suited for large and complex images. • In this scanning each point is represented by 24 bit- • 8 bit for Red, • 8 bit for Green, • 8 bit for Blue. www.ustudy.in

19. File Formats The scanned image can be stored in different file formats. • Bitmap File Format - BMP • Tagged Image File Format - TIFF • CompuServe's Graphics Interchange Format – gif • JPEG - Joint Photographic Experts Group www.ustudy.in

20. Bitmap File Format • Using this format we can store full color images without compression the size of bmp file is large. www.ustudy.in

21. Tagged Image File Format • Using this format we can store color image with LZW compression. • This format reduces the file size without any loss of quality. www.ustudy.in

22. CompuServe's Graphics Interchange Format • Using this format we can store images using indexed color www.ustudy.in

23. Joint Photographic Experts Group • Using this format we can store images in a lossly compressed manner. • This reduces the file size. • Color depth is 24 bits. www.ustudy.in

24. Color Scanner www.ustudy.in

25. Color Scanner • A color scanner is a device capable of capturing images in color. • After capturing it converts then into digital images that can be read by computer for display and storage. www.ustudy.in

26. The End ….. Thank you ….. www.ustudy.in