Accessible Mode - Clipped Text Detection
In Accessible Mode, TopOCR's Column Straightening function will also activate a function called "Clipped Text Detection" to alert you to the possibility that your document has been placed too close to the edge of the camera's capture area.
If this occurs, then it raises the possibility that part of the document is completely out of the camera capture range.
In addition to the Clipped Text alert, the Column Straightening function will actually remove the clipped column from the image.
It does this because generally clipped text columns happen when you are scanning both pages of an open book or magazine and a portion of one of pages is outside the camera's capture area.
By removing the clipped page, you preserve the integrity and OCR accuracy of the page that's not clipped.
Column Straightening and Clipped Text Detection will work best when your document is placed on a clean, white background that does not have any extraneous objects like pencils or coffee cups in the image capture area.
These objects, as well as a dark background make it harder for Column Straightening and Clipped Text Detection to function effectively.
If TopOCR does detect that the text is too close to a particular edge, it will use its Text To Speech system to notify you.
For example, after you start scanning an image, it might say, "left side of document may be clipped". In that case, you would move your document a little to the right and try scanning again.
TopOCR will check for clipping on all four sides of the document, and will also inform you if multiple sides are clipped.
If you find however, that despite your best efforts that Column Straightening and Clipped Text Detection are not performing well with your documents or document camera, then you can simply turn them off by pressing the F9 or 9 key.
Making a Better Document Positioning Mat
Most document cameras are provided with a rubberized document positioning mat that have visual positioning guides to help you place your documents for image capture.
Unfortuntaely, none of these were created with Accessible Users in mind. It's possible to create a very effective Accessible Image Capture Mat with materials you find around the house or that you can buy in any general store for less than $5!
First, you need a white flat surface, we've used everything from white cardboard to a large sheet of white paper and even a large white Tupperware lid.
With your document camera plugged in and operating with TopOCR's Real-Time Document Camera Image Preview and Capture Dialog, place your document camera at the top end of this white surface.
Then place a sample document or book below the document camera, and while viewing the image in the Preview and Capture Dialog Window align it so that the document or book is perfectly straight.
Take some white or clear tape and place strips of it around the edges of the document camera and around the edges of the document or book.
From then on, a blind person can feel the outline of the tape and place the document camera and document or book knowing that they will be properly positioned and aligned.
This approach that we use is pretty general, and we've observed blind people who've further improved upon this basic idea.
One such approach was to place a piece of tape in the middle of the bottom of the document camera and another in the middle of the document camera's taped outline and then also aligning these by having them touch.
In all cases nothing more complicated has been used than a flat white surface, some white or clear tape, and a few minutes of someone's time.