Thresholding command provides cleaner CAD data

Softcover have added thresholding technology to Scan2CAD v7.3, the latest release of their low cost raster to vector converter.

Softcover has added thresholding technology to Scan2CAD v7.3, the latest release of its low cost raster to vector convertor.

Thresholding improves the sharpness of scanned images by dynamically separating the foreground drawing detail from coloured, tinted and or dirty backgrounds.

Scan2CAD converts scanned technical drawings into DXF vector files for editing in any PC CAD program.

The accuracy of its vectorisation is greatly influenced by the quality of the scanned image it is given to convert.

Now, by applying Scan2CAD's thresholding to colour or greyscale scans, engineers can improve their chances of a useful conversion result by first removing background "noise" and sharpening the essential drawing detail.

Other new features in Scan2CAD v7.3 are a new wide format scanner interface, a dedicated driver to support drawing image acquisition from the popular colourtrac SmartLF wide format scanner, single mouse click automatic drawing rotation (Deskew), faster, easier, more intuitive zooming, new-look icons and several improved commands.

The Scan2CAD demo is a free raster editor which allows thresholding to be used on an imported image.

A fully working demo of Scan2CAD with thresholding and colourtrac SmartLF driver can be downloaded from the Softcover website.

Simple and adaptive thresholding for colour and 256 grayscale raster enhancement is the major new feature in Scan2CAD v7.3.

Although many scanning software programs include thresholding, Scan2CAD is the first low cost raster to vector conversion program to incorporate thresholding as a dynamic raster editing tool.

Simple thresholding is designed for drawings with uniformly tinted or coloured backgrounds, like blueprints, sepia prints and dyelines etc.

Adaptive thresholding is for scanned images where both the darkness of the background and the darkness of the drawing detail vary in different places across the image.

Both methods aim to get the best defined drawing detail against a background that is as white as possible.

Simple thresholding is applied globally across the scanned image.

By moving a threshold slider bar the user can choose the optimum point, the threshold, at which to separate the background and foreground detail.

All colours with a value lower than the threshold are set to black, all colours with a higher value are set to white.

Adaptive thresholding is applied locally across the scanned image.

Unlike simple thresholding which uses one threshold value over the whole raster image, Adaptive thresholding divides the image up into localised areas or Windows and uses different, more appropriate threshold values in each Window.

The user sets the size of the Window and a background value, both of which are controlled by a slider bar.

Once the scanned raster image has been enhanced with thresholding Scan2CAD's vectorisation can be run with a much improved chance of getting useful results, particularly from poor quality drawings.

What makes Scan2CAD's thresholding particularly powerful and useful is that Scan2CAD retains the scanned image in memory, allowing it to be modified until another function is used on the image.

The second major addition to Scan2CAD v7.3 is a new large format scanner interface for acquiring and controlling the scanning of monochrome, greyscale and colour images at a range of different resolutions.

The first wide format scanner to be integrated and supported by Scan2CAD is the colourtrac SmartLF range.

More will follow.

A straightforward yet fully functional scanning interface allows the user to choose all standard paper sizes, as well as set custom sizes.

If set to auto size Scan2CAD will correctly sense the appropriate paper size.

Drawings can be scanned in portrait or landscape.

An automatic rotate option turns large drawings scanned in portrait mode by 90, -90 or 180 degrees so that they appear in the correct orientation on screen.

Monochrome (black and white) images can be automatically deskewed as part of the scanning process.

Steve Hannath, Softcover's Marketing Director, said: "Our aim is to add practical new tools and capability to Scan2CAD so that our users have a powerful, low cost solution to the many problems that raster to vector conversion throws up".

"The combination of large format scanner support with integrated thresholding gives Scan2CAD a new capability in an area we've not previously supported".

"Thresholding is primarily designed to improve poor quality scans from dirty or tinted drawings".

"There are very many poor quality scans out there that confound raster to vector conversion software".

"What may look like a good or half-decent scan to the CAD operator's unpractised eye is often the drawing from hell for vectorisation software, no matter how much it costs".

"Scan2CAD v7.3's new thresholding command gives those who are prepared to use it the chance to get a much better conversion result".

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