Document Camera | doug woods

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Using a Visualiser with the Visually Impaired

Monday, January 16th, 2012

A visualiser is essentially a static webcam that can be used to project images of real objects or text onto a screen, an interactive whiteboard or a webpage. By projecting an image onto a whiteboard or a large screen, they can be used in whole-class or large group teaching. By linking them to a server the image can be sent to a network of computers, including remote computers, or to individual handheld devices. The image can be, and most often is, displayed in real time but the image, or a stream of images, can be recorded, stored and used at any time. The visualiser is a very versatile piece of kit that can be used in many ways to enhance teaching.

What I want to touch on in this post is the use of a visualiser for pupils with visual impairment. Now, instinctively, the first thing you think when working with a pupil with visual impairment is that the image should be both clear and large. The visualiser can easily provide this; it displays the image of the object under its lens and projects this onto a screen. The image can be of a two dimensional object, such as text or picture in a book, or a real three dimensional object, it can even be of a moving real-life object, such as a spider (or ladybird for the squeemish). Careful use of a light source can help minimise shadows and/or emphasise the 3 dimensional nature of the image. The image produced from the visualiser can be enlarged to present it clearer to the pupils; this can be especially useful if you are teaching a large group or if you have a pupil with visual impairment who just happens to be sitting near the back.

It is traditional wisdom that images should be larger than life when teaching a pupil with a visual impairment but really the efficacy of this depends upon the nature of the visual impairment. What I’d like to suggest is that we do the opposite; we take the image produced by the visualiser and we shrink it and then shrink it even more until it is actually smaller than in real life.

Why do I suggest shrinking it like this? Well let us take the case of a learner whose visual depth is no more than a couple of centimetres in front of his eye. A learner with such an impaired visual field can rarely take in the whole of an object but has to move their head and eye around an object in order to perceive it all. If we present a real-life sized image to such a learner, they will experience difficulty perceiving it. If we have enlarged it, then we have only compounded the difficulty the learner experiences. If, on the other hand, we have shrunk the image to less than life size, we have increased the opportunity of this learner to perceive the whole object and, thereby, improved the learning opportunity for that learner. This, of course, assumes that the learner is able to get close enough to the projected image!

I make that last remark because, while it may be the case that the image can be projected onto a wall, projector screen or IWB, the learner may be prevented from getting close to the projected image by furniture or objects placed in front of or attached to the a screen. The learner would also have to be able to locate the small image among a vast mass of white space. Perhaps, in this instance, feeding the visualiser image to a server and then to a handheld device might be a better solution.

There may be many other ways of using a visualiser with visually impaired learners and, indeed, other obstacles to overcome. I simply present this as an idea for their use and a demonstration of their versatility.