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A screen reader is advanced software that helps blind users in reading the output on the screen. Screen readers are capable of reading whole text, selected text provided by user search to frame reading. These range from freeware to highly expensive software. JAWS is software developed by freedom Scientifics and Window Eyes. Serotek, developed by System Access is a screen reader that can be run directly from the internet. Windows narrator is a simple OS screen reader. Apple and Linux Gnome Desktop have sophisticated screen reader. Some of the optical recognition software's are Kurzweil 1000 and Open book.
In 1821 Louis Braille developed Braille, a secret code for the military to communicate in the dark. Braille was then used by the blind to read. The Braille display uses similar electro mechanical technology to raise letters as in the Braille. The Braille display can be combined with speech synthesizers. It uses the peizo effect of crystals for raising the letters. These letters expand when voltage is applied.
Advanced development of the Braille display is the rotating wheel Braille display. It was developed in 2000 by National Institute of Standards and Technology (NIST) by Leuven University in Belgium.
Computer technology dominates in human's day to day life. Common man will have to rely on computer technology for various tasks. Where the information and knowledge is update in the internet, it provides convenience and ease of access to users to find their right kind of information.
A visually impaired person would be deprived of using such technological advancements as he cannot read. It is good to see that there are certain technologies to help the blind use the computer. The screen reader is software that helps in reading what is present on the screen to the user, it reads out the text in human voice. There are various types of screen readers available commercially depending upon user needs. Simple OS screen readers are also available. Some of the cheaper technology is the scanner and OCR (optical character recognition).
Another technology that uses screen reader software is the Braille display. Using electro mechanical technology it raises the specialized screen to help blind users read text in Braille. A development in Braille display is the rotating wheel display. It provides ease to users as they do not have to move their fingers. A wheel will keep rotating with Braille characters running over it and users can just place their fingers over it
2 .Current technologies:
2.1 Screen readers:
Computer users with blind disability mainly depend upon screen reader software for most computing actions. In simple words it is the software which converts text into synthesized speech and so that blind people are able to listen the activity on the screen.
Screen reader acts as the brain of any talking computers. The screen reader not only provides the output through speech but also acts like the interface between blind user and computer. Knowing what is on the screen is just the beginning, and then blind user can interact with computer by issuing commands through some keyboard shortcuts.
Blind users can steer the web page content in many ways through screen readers. Users can make screen readers to read everything from top to bottom on the screen, or even one line at a time or users can use tab keys to navigate from link to link. The users can also navigate from one heading to another, from one frame to next.
The most useful browser for using screen readers is Microsoft Internet Explorer. There is a classy use of a special collaboration between internet explorer and some screen readers. Internet explorer is the intelligent browser because it is able to surpass along construction and other information of the web page to the screen readers. Common screen readers include JAWS or Window Eyes to read each frame in turn, including the title of the frame. But it is strongly discouraged to use frames.
Screen readers can transfer text into Braille characters and sent to Braille display. This display has small pins that can be raised or lowered to form Braille characters that can read by moving fingers. Blind users can read this Braille display quickly with their advanced Braille skills. Hard copy outputs from Braille printers are useful for Blind users
2.1.1Limitations of screen readers
Screen readers are quite powerful in their ability but also have some limitations in their approach. It cannot play the whole role for visual experience. But there are some ways to compensate for screen reader weakness.
Blind users cannot expect screen readers to describe the image. But it can convey the meaning of an image and also it can read texts in the document that can be considered as alternative for that image.
220.127.116.11 Visual Layout
Screen readers cannot describe completely how the web page is organized. It can read only one word at a time. And also it cannot skip the unwanted contents like advertisements
18.104.22.168 Data Tables
It is very tough for blind user to understand data tables when it is large in size. At the end of the table rows the user cannot remember the first few rows read by screen readers.
2.2. Software's for Screen Readers:
2.2.1. Window Eyes:
Window -Eyes is the more reliable software for screen readers. Window-Eyes gives the blind people required control on they hear and how they hear it. It has improved Braille support that control is absolute to how they feel .It acts as the key to open the world full of information. It is the leading software for blind people, which converts components of windows operating system into synthesized speech. Window -Eyes integration in the operating system provides the blind people can access the windows instantly.
2.3. Optical character Recognition (OCR):
Optical character recognition is the electro translation of images of hand written, type writer or printed text. While scanning a paper it produces just an image file we cannot edit that and also computer cannot understand the text in it. But in optical character recognition images are converted into recognized characters.
Optical character recognition technology provides blind people and visually impaired persons the ability to scan printed text. That text is read back in synthetic speech. Using this technology we can convert photographs, line art into recognized text
There are three major elements in OCR technology;
The document or photographs is scanned by a camera. Then Optical character recognition software converts the images into recognized character or words. Then speaks the recognized text by the synthesizer in the OCR system. All information stored in an electronic form. It can be stored in personal computer or in OCR itself
3 Reading by touch:
Braille system is generally used by the people who are blind. Braille is not a language to learn. It is just another way to read and write our language. In this world there are many numbers of blind or visually impaired people. But not all of them are learned Braille.
There are three reasons for this:
Less number of Braille teachers
Teachers do not have enough training
Many institution think they do not need Braille instructors
Braille generally consists of cells which are formed by raising dots .There are six dots needed to build a cell and arranged two in a row and three in a column. The cell can represent a letter in alphabet, numbers, punctuation or even a word. The existing or absence of dots makes the different between codes. The blind person reads these raising codes by running his fingers over the cells.
The Braille system of communication was devised in 1821 by Louis Braille, a blind man. At the age of 15 Braille developed a code system with 6 dot cell. Previously Braille system was used for soldiers to communicate silently in night time called Night writing. It was so complex for soldiers later Braille modified with 6 dot cell
3.1 Braille systems:
There are two primary systems in Braille code named as Grade one or UN contracted and .Grade two contracted Braille
Grade one system is used to represent every single letter of the word. While this type of system is not used most often for reading materials, moreover it is useful in labelling for Braille learning people. In a word each letter has separate cell. It is said to be as Alphabetic Braille. Using this alphabetic Braille, shopping lists, telephone numbers or brief notes can be written.
Grade two or contracted Braille is the most common Braille system which is taught to school children's learning Braille. It is standard method for Braille users. It is also called Literary Braille. Most often books and magazines are written in Grade two or Literary Braille since it needs less space than the Grade one Braille. Moreover in order read and novels, articles in Braille, it is necessary to learn literary Braille.
3.2 Braille reading techniques:
A Braille reader must develop new skills in order to read Braille without mistakes. The most important thing for Braille readers is the ability to move his fingers over words in smooth and even pressures manner. There are different techniques and styles used for understanding and development of Braille. Braille could be read fast by the blind users who use their index fingers of both hands to read the cell. There is another reading skill which blind users use their right hand at the end of the line and starts next line with left hand simultaneously. It is necessary to memorize alphabet, numbers, punctuation and contraction. Finger sensitivity is more important to feel the dotted cells.
4 Haptic Technology:
Haptic technology is the interaction with user through the sense of touch by applying some kind of force, vibration or motions to the user. It is tough to teach some kind of mathematics without using pictorial or graphical presentation of function. There are many haptic applications at present .the blind people can feel the shape of a function using PHANToM based haptic graphs.
We need touch feedback to manipulate objects successfully. For blind people touch is more effective so it is their primary sensory feedback. Haptic receptors are present all over the body. That has been classified into two categories.
Cutaneous receptors present below the surface of the skin so that it can feel temperature, pain and pressure.
Kinesthetic receptors are present in muscles, tendons and also in joints that responds to the position of our limbs and also their movement
PHANToM device has the technology that makes blind people to feel virtual objects. It is used to instantiate virtual objects at very high resolution. This is six degree of freedom device, consisting of a motor controlled jointed arm. The blind people can access this device by placing their finger in a thimble at the tip of the device. This affords a very realistic interaction with the objects
5 Current researches:
5.1 Research for Blind shoppers:
In America scientists have developed a robot for blind people that could help in shopping and to find paths in large buildings. To search the items in shop it uses radio frequency identification tags and laser is used to avoid collisions. It was created by Professor Vladimir Kulymin at Utah State University.
Already shop floor trails have begun. It is also useful in airports. Using this robot in shop the blind people can grab their exact product which they need at that time using radio frequency identification tags. But until nom radio frequency tags is used only in particular shelves to locate the product shelves. Soon the robots can identify each product in the shop with bar code reader fitted in robot.
5.2 Refreshable Braille Display:
Refreshable Braille display is an electro mechanic device for displaying Braille cells. The refreshable Braille display produces Braille by raising and lowering pins in flat surface. Blind people can make use of this as they cannot use computers. Speech synthesizers are used for same purpose. The blind people can use both of this depending upon their situations and needs. Normally Braille cells 40-80 are available. It is used to display digital information present on the internet. It is the robust reading device for a blind user.
The dots are raised in a mechanism where it uses the piezo effect of some crystals. These crystals expand when a voltage is applied to them. Crystals are present in each dot so that it can be raised to form a cell.
Eight crystals join to form a cell so it is really expensive. There are several researches going on to produce the cheap display .So it is the main drawback for this display.
The surplus technological assistance to help the blind to cope up in using the computer has developed a lot. However these technologies are not user friendly and expensive. While inexpensive software's are present, they do not perform specialized tasks. The user takes the trouble of even hearing unwanted information like advertisements present on the internet. It is difficult for the user to keep in track of what he is listening. Navigating back to some lines becomes a difficult task.
Presentations in the form of tables cannot make sense to the user when it is being read row wise. Images without explanation are another big drawback where it cannot be interpreted to users. The keyboard is not a perfect substitute for the mouse. A blind person cannot use the mouse while performing all tasks with the keyboard remains to be a real challenge. Braille display is a good technology that helps users in reading but they are very expensive. In an instance only 40-80 cells can be raised.
While all these technologies have their own drawbacks, the rotating wheel Braille display is more users friendly. The user just has to place his finger over the wheel as the wheel rotates Braille prints. This technology is much inexpensive than the others.