Little engines that scan: compact and capable, these 12 hand and page-feed scanners are an inexpensive way to deliver images to your system - includes a related article summarizing the review - Hardware Review - Evaluation

Home Office Computing, Feb, 1994 by Stephen W. Plain

A PHOTO IN YOUR NEWSLETTER, YOUR SIGNATURE ON A thousand-piece direct-mail campaign, and a magazine article with vital information on expected market downturns all have one thing in common. They're good reasons to consider buying a hand scanner.

Hand scanners let you put information such as this into your computer, where you can take advantage of tools like image-editing programs that enhance photographs or word processors that search for every instance of the phrase profit margins, for example. Hand scanners can't compete against higher-end flatbed scanners in all respects; flatbed designs are a better choice for high-resolution scans or for heavy-duty OCR (optical character recognition) work. But hand scanners take up less space, are portable, and prove more convenient for scanning in the pages of bound books as well as small images or a section of a larger image.

And, of course, hand scanners are still cheaper than flatbed units. A hand scanner that delivers 256 shades of gray can be found for well under $200, while full-color handheld models sell for about $400 to a little over $500. The price gap between these and full-color flatbed scanners is steadily decreasing, however the HP ScanJet IIcx flatbed, for example, costs as little as $1,000 discounted.

Falling flatbed prices have actually spurred innovation in the handheld market. Some manufacturers now have designs that compensate for jittery hands, which make it harder to move a hand scanner slowly and straight down a page. The higher the resolution and the more gray shades or colors you require, the more data the device has to pick up, and the slower and steadier you'll need to travel. Going too fast or failing to scan in a straight line usually results in a distorted image. To combat this, Microtek, KYE International Genius, and NISCA sell products that let you feed pages through or that automatically propel themselves across the page, helping to eliminate the human error factor.

The maturing laptop market has also had an impact on design. Hand scanners like the Logitech EasyTouch can be moved around easily because they connect to the parallel port rather than a proprietary interface board. NISCA's NISCAN Page goes a step further--it's boardless and battery operated, too.

Pick, Choose, and Use Hundreds of hand scanners exist, many of them repackaged versions of another vendor's product. For this review, we looked at 12 grayscale and color hand scanners from the companies with the largest market share, as well as innovative entries like Microtek's Scooter.

We required all the scanners to support a minimum 300 dpi optical resolution and 256 true shades of gray. (Some 300 dpi scanners achieve resolutions as high as 600 dpi via software interpolation; this is the process in which extra pixels are added via the software so that a scan at a lower resolution is made to look as if it were scanned at a higher resolution.) Grayscaling represents the colors or tones of an image with shades of gray; while 16 or 64 shades of gray are sometimes used (and few of these scanners support these settings), the finest-quality grayscale images are achieved using eight bits of gray, or 256 shades. We looked only at color units that supported the full spectrum of visible colors--and that means 24 bits (16.7 million) of color. You probably won't need a more expensive color hand scanner, however, unless you must output the scanned images to slides or want to use them in onscreen applications like multimedia presentations. All these scanners also have a text or line an mode (one bit) that represents text or a drawing with no intermediate shades.

Keep in mind that scanning 256 shades of gray or 16.7 million colors at high resolutions can result in huge image files and increased processing time. Using a lower resolution like 100 dpi for images drastically reduces file sizes, and some speed and quality problems. Every manipulation of an image, such as resizing, results in a small loss of detail. You'll want to start with the highest-quality scans to get the best output, for example, from high-resolution devices like film recorders for making slides. A 300 dpi laser printer, however, won't do any more with a 200 dpi or better continuous-tone image than it will with a 100 dpi image. For OCR, you can increase the accuracy of recognition, especially when using small point sizes, by using higher resolutions, and you should always scan line an at least at the resolution of the output device to avoid jaggies. Even then, however, we found that the OCR process is still tricky enough that you'll probably have to make some manual corrections.

We tested each product's ability to scan in both black-and-white and color photographs at either the scanner's highest resolution, or the resolution that provided accurate images. Most hand scanners (though not the page-feed designs) are limited to a four-inch scanning width, so their software's adeptness at stitching together larger images (either automatically or manually) scanned in over multiple passes is important. We tested these abilities with both an 8-by-10-inch photograph and a letter-size page of text. We also evaluated the accompanying OCR software for accurate recognition of different fonts and point sizes, as well as for the ability to recognize and isolate columns and handle text set against a dark background.