Introduction to Scanners

Transcription

1 Introduction to Scanners Principles of Information Technology 1

2 What is a Scanner? A scanner, simply put, is a device used to analyze an image and process it. Scanned Image 2

3 One size does not scan all! There are different types of scanners for different types of documents that need to be scanned. Flatbed Scanners Sheet-fed Scanners Handheld Scanners Drum Scanners 3

4 Flatbed Scanner Used for scanning most documents, photos, and even flat objects from a PC or laptop Works like a copy machine Scans documents placed face down on the glass (scan bed) Most common type of scanner 4

5 Sheet-fed Scanner More portable than a flatbed scanner Used to scan paper documents and photos The paper moves through the scanner Usually smaller than a flat-bed and portable 5

6 Handheld Scanner Smaller than the previous two scanners The user must move the scanner across the document Image quality is usually lower 6

7 Drum Scanner Used by the publishing industry Document is placed on a glass cylinder Generates very high-quality scans 7

8 Using Your Scanner Most flatbed scanners are connected to the computer via the Universal Serial Bus (USB). A software program called a TWAIN driver is used by the computer to communicate with the scanner. An image editing program can then be used to manipulate the scanned image. 8

9 Connecting the Scanner Most modern scanners connect to the computer through the USB. 9

10 Scanner Software The TWAIN is a standard of communication between the computer and scanner that allow images to be directly scanned from an image editing program. All scanner manufacturers agree to use this standard. The TWAIN driver controls the scanner and serves as the interface between the scanner and your graphics program. TWAIN is not an acronym for anything, but 10

11 What is TWAIN? Twain is an old form of the word two. The TWAIN software refers to the computer and scanner and the difficulty in connecting the two. The developers took the word from Kipling's "The Ballad of East and West" "...and never the twain shall meet..." Allows 3 rd party software applications to access the scanner to import images. 11

12 Scanning a Photo Place the image face down on the scanning bed. The scanner will have a marker indicating where the top of the image should go. 12

13 Scanning a Photo Most applications that are TWAIN compliant will allow you to scan the image directly into the application. 13

14 Scanning a Photo Some applications are not TWAIN compliant. The scanner manufacturer will usually provide a stand-alone application for scanning images. You can scan images and save them using their application. Next, open them like any other image in your application of choice. 14

15 Scanning Formats Depending on your scanning software, you may have different options of file formats in which to save your scanned image or document. Images may be saved as jpg, bmp, tif, or png. Documents may be saved as pdf or any of the image formats 15

16 .bmp The BMP file format, sometimes called bitmap file format, is an image file format used to store bitmap digital images. BMP is a very simple bitmap format. It doesn't support any photo-specific features and most importantly, it doesn't support color management. 16

17 .tif Tagged Image File Format (abbreviated TIFF) is a file format for storing images including photographs and line art..tif images are considered lossless, meaning when compressed they do not lose any of the data that renders the image, allowing the image to maintain its resolution. 17

18 .jpg.jpg is the most common image format used by digital cameras and other photographic image capture devices, and it is the most common format for storing and transmitting photographs on the World Wide Web..jpg images are considered lossy, meaning when compressed, they lose some of the data that renders the image, resulting in a lower resolution image. 18

19 .png Portable Network Graphics (PNG) Designed to replace the GIF format. 19

20 .pdf The Portable Document Format (PDF) is the file format created by Adobe Systems in 1993 for document exchange. PDF is a fixed-layout format used to represent two-dimensional documents in a manner independent of the application software, hardware, and operating system. Each PDF file encapsulates a complete description of a 2-D document (and sometimes embedded 3-D documents) that includes the text, fonts, images, and 2-D vector graphics that compose the documents. 20

21 After Scanning After scanning, you may need to modify your image in a graphic editing program. Crop Brightness Contrast 21

22 Crop To crop an image means to cut away, or trim, the image. 22

23 Crop 23

24 Brightness Refers to the lightness and darkness of a color Also referred to as tone or value Original Image Increased Brightness 24

25 Contrast Contrast is the difference in visual properties that makes an object (or its representation in an image) distinguishable between other objects and the background. Original Image Increased Contrast 25