Scanners

Nagat Zeinelabdin

Scanners

An image scanner is a device that optically depicts an image (i.e. of printed text, handwriting, or an object) and transfers it into a digital image. There is a variety of desktop scanners where the document is placed on a glass window for scanning. Hand-held scanners, where the device is moved by hand, have evolved to 3D scanners used for industrial design, reverse engineering, measurement, and other applications. Modern scanners use a charge-coupled device (CCD) or a Contact Image Sensor (CIS) as the image sensor, whereas older scanners called “drum scanners” use a photomultiplier tube as the image sensor.

Due to increasing resolution needs and new required features such as anti-shake, digital cameras have become an attractive alternative to regular scanners. While still having disadvantages compared to traditional scanners (such as distortion, reflections, shadows, low contrast), digital cameras offer advantages such as speed, portability and gentle digitizing of thick documents without damaging the book spine.

At the DLI we regularly and intensively use image scanners. We use them to enter typed texts from books or textbooks into the computer, especially for homework through the Blackboard program. In teaching foreign language, we often find useful reading material with tasks or questions already made; we use these after we scan them in the computer. We actually use them as PDF expanded files. We also use scanners to save documents for students’ counseling or achievement certificates after the documents are signed by the students.
 

The image scanner is a very useful tool of teaching. Advantages are numerous. First, they represent a simple and a cheap tool usable at office and at home. Second, they are very easy to learn and use. Third, they make easy the transfer of ready hard copy material into electronic files that can be set and dealt with electronically. Third, they offer a tool to store signed documents in an online safely kept location and can easily be sent to other computers as a file. They make possible an environment-friendly paper use; that is by providing digital imaging as an option to paper-and-ink printing. It is a useful tool in the hands of teachers, and not to students, to ease and facilitate teaching.

Disadvantages, on the other hand, include a noticeable reduced resolution of written materials. Secondly, scanning lessons or part of a textbook is tedious and time consuming.