Ron Horii's Tech Pages:
Scanning 

Contents

Introduction

Where is the vast majority of civilized man's knowledge and expression stored? It's not in people's minds. It's not on tape or computer media (yet). It's mostly on paper or canvas in libraries, galleries, museums, schools, businesses, and homes around the world. This includes knowledge and information dating back to the beginning of human civilization. What's the big problem with this information? It's hard to find, and it's hard and slow to get to. You often have to physically travel to places, sometimes far away, to find them. Even when you get there, the material may be damaged, lost, restricted, checked out, or not what you're really looking for. Searching for the information can be very time-consuming, even with computerized card catalogs, because you still have to find the actual works and manually scan through them. Because of the difficulty of getting at this information, it limits its usefulness. Productivity and progress is thus limited.

The computer is a tremendous tool. It enables a user to search, access, manipulate, file, reuse, and transmit information anywhere in the world instantly. The trick is to get the information into it. The scanner is the link between printed information and the computer. The scanner can take this information and turn it into a form that a computer can work with. It opens up the computer to an enormous and virtually unlimited source of input. With the power of the computer applied to this source of input, the possibilities are staggering. Information is power. Combine that computer processing power with the instantaneous and widespread capability of disseminating information on the Internet and the Worldwide Web, and you have a potential for empowering the average person to a degree that's unprecdented in human history.

That's all impressive from a global standpoint, but for the average user, the question is: what can a scanner do for me? Here are some general uses:

• Turning your computer into a simulated fax machine.
• Turning your computer and inkjet printer into a color copier (though a very slow one).
• Scanning documents and graphics for filing away in computer-accessible libraries.
• Scanning printed documents and using OCR (Optical Character Recognition) to turn the information on the pages into data that can be fed into work processors, spreadsheets, or databases.
• Scanning drawings, charts, and photographs for publishing on the Web or intranets or sending by E-mail.

• Microscope photographs, X-rays, spectrographs, chart recorder traces, chromatographs, or other hardcopy images, can be scanned in and filied away with associated data. They can later be used for reports or presentations.
• Polaroids of writing on blackboards, hand-written view foils or meeting charts can be scanned to preserve them and be able to digitally access them. It's even possible to OCR them if the handwriting is legible. The same can be done for hand-written notebook entries.
• Hardcopy forms can be scanned to turn them into softcopy forms. Information written on the forms can be OCR'd into a computer.
• Hand-drawn schematic diagrams can be scanned, turning them into CAD schematics. The same idea can work with actual printed circuit boards or with hand-drawn mechanical drawings.
• Industrial design: scanning photographs of real equipment and furniture, as well as people, using a image editing program to move the objects around to find the optimal arrangements.
• Security: scanning photographs, fingerprints, and signatures of personnel for online security verification.
• Online sales: scanning pictures of products for advertizing on the Web.
• Labels: scanning pictures of components or the parts themselves to put on labels for drawers or boxes.
• Online operating manuals: photographs of equipment can be scanned in. Using hotspots, image maps, and help files, operators can click on the different parts of the equipment to find out what they do.

• Scanned personal snapshots can be used to make personal Web pages (like mine).
• Family snapshots can be scanned to make greeting cards, calendars, Christmas letters, Christmas ornaments, T-shirt iron-ons, bookmarks, posters, signs, awards, children's crafts, and gifts.
• Old family pictures can be scanned in and retouched with an image editing program. This can be used to remove scratches, dust spots, streaks, rips, and former in-laws. It can also be used to colorize black-and-white photos or improve the contrast, sharpness, and color of color photos.
• Family tree albums can be created with scanned old photographs, and with personal stories on each family member.
• Color pictures from books and magazines can be scanned and included in school reports, posters, or science projects, without having to cut up the sources or make expensive color copies of them.
• Photographs of pets and children, as well as fingerprints, can be scanned and stored. If they become lost, this information can be E-mailed to the proper authorities or posted on the Web to help locate them. Tattoes, birthmarks, or other markings on certain parts of the body (I won't specify which) can be scanned in directly.
• Photographs of property can be scanned in and stored for record-keeping and insurance purposes, or used to make sales posters or posted on the Internet for sales. Stamp, coin, trading card, some jewelry, and small (dimension-wise) art collections can be scanned in directly.
• Sheet music can be scanned in, converted to digital form and used to program and play on MIDI-compatible instruments. If you plan an instrument, you can practice playing with an orchestra by scanning in a whole orchestral score, editing out your part, and having the computer play the rest, while you play along.
• Some homework exercises require copying down sentences and correcting them. Instead of re-typing them all in, they can be scanned in and OCR'd, then corrected with an editor. (This should only be done with the teacher's permission, and not with the use of spelling or grammar checking programs.)
• Line drawings can be scanned in and imported into a paint program. Using a color fill tool, children can color in the drawings like a computerized coloring book, print out their handiwork, then E-mail a copy to grandma.
• Children who have to stay home due to illness can scan their homework in and E-mail it to their teachers for correction to help stay up with their classes. Teachers similarly can scan in new homework and E-mail it to their students at home.
• Some people with large home libraries enter the book titles into computerized databases to help catalog them. However, they may forget what the books are about. If they scan in the book covers or jackets, this can help. The same can be done for CD's, cassette tapes, and video tapes.
• Magazine and cookbook recipes can be scanned, OCR'd, and filed away in recipe databases.
• Instead of saving mountains of old magazines or boxes of clippings, important articles can be scanned and filed, and the magazines can be thrown out.
• Some dry food items, such as pasta, beans, cookies, candy, dried fruit, nuts, etc. can be put in a clear bag and scanned to make illustrative labels for storage containers. The same can be done for other items, such as pencils, paper clips, needles, buttons, and small toys.
• Instead of pressing flowers and leaves in books to preserve them, they can be scanned in directly on a scanner and be preserved electronically, which preserves their colors when they're fresh.

Predictions

I predict that scanners will soon become so important that they will be bundled with PC's like modems, and sound cards. A low-end scanner is about the same price as a high-end sound card, and for office use, a scanner is much more useful than a sound card. Printers and scanners complement each other, so it's likely they'll be bundled together with compatible resolution.

I also predict that the huge memory requirements of scanned images will drive the need for more powerful computers with enhanced graphics-handling capability, more RAM, and more storage. In the storage area, this not only includes larger hard disk drives, but high-capacity removable storage for archiving and transporting data. Standard 3.5" 1.4MB diskettes are inadequate for this task.

As it becomes easier to incorporate color graphic content into documents, this will increase the demand for high-quality color output devices, such as inkjet and color laser printers. The resolution and quality for both scanners and printers will increase until they meet or surpass film and high-quality printing processes.

Graphics made the World Wide Web the instant phenomenom that it is today. Scanners put more power into the hands of small office, academic, and home users. Scanned images will proliferate even more on Web pages (like this one), which will increase the demand for more bandwidth on the Web.

Scanners may displace dedicated fax machines in some office applications where fax demands are light and a computer, printer, and modem are already present. For multiple-page faxing, an auto-document feeder is useful. A scanner, with the appropriate hardware and software at the receiving end, can do something no ordinary fax machine can do: send high-resolution color faxes.

Digital cameras will proliferate and will displace film cameras to some degree. They won't, however, replace scanners for a long time. The resolution, in terms of total numbers of points digitized, of a digital camera is orders of magnitude smaller than a scanner. A high-end digital camera, costing in the $1K+ range, will have a resolution of 1000+ points total across the entire image. A low-end scanner costing under $100 can resolve (with interpolation) 1000+ points every fraction of an inch. A digital camera has the advantage of portability and immediacy and is very useful, but it's a different use from a scanner. It's like the difference between RAM and hard disk storage. The two are complementary, not mutually exclusive. I do believe that digital cameras will become more popular as they get better and cheaper, but they'll displace film cameras, not scanners.

Types of Scanners

There are several types of scanners. The type to get depends on your application:

Scan Bit Depth 

Scanners convert analog data (page images) to digital data. Digital data can have different bit depths depending on the application and scanner hardware:

• 1-bit: used for black-and-white line drawings and text, faxes, and OCR work.
• 8-bit monochrome: used for scanning black-and-white photographs
• 8-bit color: also called pseudo color, not directly supported by scanners, but scan files can be converted to this, the color depth for GIF files and MCGA video adapters.
• 16-bit color: also called high-color, 65K colors, also not supported directly by scanners, but scan files can be converted to this.
• 24-bit color: also called true color, for color photographs, the maximum bit resolution defined in most common file types and the minimum bit resolution for most color scanners.
• >24-bit color: 30, 36 bits are common. A 10-bit or 12-bit analog-to-digital converter are used for each color (red, green, and blue). There are few common file formats that support these bit depths (TIFF is the only one I know of), but the extra bits are used to provide extra dynamic range for the scans, especially in resolving detail in dark areas and highlights. For high-quality photographic work, the extra bits are worth it. For more information, see "Will 30-bit and 36-bit Scanners Give Better Scanned Images? "

Scan Performance Measurements 

Conditions:
Scanner: Microtek Scanmaker E3
Maximum resolution: 300 X 300 DPI optical resolution, 2400 X 2400 interpolated resolution
Interface: SCSI
Computer: Pentium 120 CPU
Memory: 49 MB RAM, 128K pipeline burst cache
Scan size: 8 1/2" X 11"

Scan Size and Time Measurements Table

* Not enough memory to scan.

This shows that scan time and memory required can vary tremendously with resolution. Color also takes much more time and memory than B&W. Scanning is processor and memory intensive, so the scan speed depends on the speed of the PC and the amount of RAM installed. The memory requirements are such that even if your scanner is capable of 1200 to 9600 DPI interpolated, you may find it impractical to use such high resolutions except for special purposes. (See Zooming In.)

Scan time may or may not be important, depending on what your application is. If you're using the scanner for photo imaging, you'll more likely spend much more time editing and manipulating the photo scan than doing the scan itself. Scan time becomes important if you're scanning in multiple pages for OCR or archiving purposes. However for OCR work, the OCR processing time can be longer than the scan time.

One problem with trying to compare scan times is that there is no standard measurement. One manufacturer may quote the scan time at 300 DPI of a 4 X 6 photo, while another may quote the scan time for an 8 1/2 X 11 sheet at 100 DPI. Independent reviewers will test all the scanners they're reviewing under the same test conditions, but different reviewers may use different conditions. I've seen in some reviews that the relative ranking of the speed of different scanners will vary with the test conditions. The PC speed and configuration can have a big effect on the scan speed. Some scanners may have built-in intelligence and rely little on the PC speed, while others may heavily use PC resources and will be very sensitive to PC speed. Scanner drivers can vary in the way they use RAM and hard drive space to stoe scans, so the scan speed can be greatly affected by the amount of RAM or the speed of the PC's hard drive.

Scan Resolution Rules of Thumb 

How much resolution do you need? It depends on your application. The more resolution, the more you pay, so you don't want to pay for resolution you don't need. However, if you have multiple applications for the scanner, get the resolution appropriate for the most demanding application you think you MIGHT have. Keep in mind that the important specification is image resolution. Image resolution is the resolution of the final output. That depends on the initial sample resolution and how much you blow it up or shrink it down. If you blow images up, you'll need more sample resolution than if you use them actual size. Conversely, if you shrink scanned images down, you need less sample resolution. If you don't know what you need, get the highest resolution scanner you can afford, or wait until the prices come down. Here are some rules of thumb on what scanning resolution is needed for different applications, based upon using the images actual size:

• 72 DPI is the number that has tradtionally been quoted to be adequate for pictures to be published on the Web at actual size. This will probably go up in the future as larger, higher-resolution monitors and video cards become more common. 72 DPI is the final resolution of the image when publishing it on the Web. You can scan pictures at this resolution, but you may get better results by scanning a picture at a higher resolution, then use a good image editor to touch it up and resample it down to 72 DPI. There's nothing magic about the number 72. See "Why 72 dpi?" for more information.
• The resolution for video displays varies with the video setting and size of the screen. (See Wayne Fulton's "A few scanning tips - Basics Part 1 - Video resolution.") A 17 inch monitor screen might measure 12 inches horizontally. If it is set to 1024x768 screen size, then the image is obviously 1024 dots / 12 inches = 85 dpi resolution in that case. A 15 inch monitor at 800x600 might be 75 dpi. A 14 inch monitor at 640x480 might be about 65 dpi."
• 100-600 DPI is adequate for graphics to be printed full-size on most inkjet or laser printers, depending on the printer resolution and desired print quality. The scan should be higher than the printer dot pitch. Too much scan resolution is overkill.
• 100-200 DPI B&W is fax quality. The standard for normal fax resolution is 204x98. High fax resolution is 204x196.
• 100-400 DPI B&W is adequate for OCR scans, depending on the font size. 300 DPI is good for 10-12 point type, 400 DPI for 6-8 point type.
• 600 DPI and higher is for professional publication-quality graphics or for zooming in and blowing up small portions of pictures.
• If you're scanning 35 mm slides or negatives, you need need much higher resolution, since the originals are relatively small. Slide/negative scanners tend to have resolutions in the 2000+ DPI range. Some flatbed scanners have special (and often expensive) transparency adapters. These can be used for scanning slides and negatives, but unless you have a very high resolution flatbed scanner or are using very large transparencies, the resolution is usually inadequate for serious publishing work.
• If you're doing high-quality scans, you need a lot of RAM and a fast PC. See my tables below. Professionals use PCs with 100's of MB's of RAM and GB's of hard drive storage. ZIP drives are popular for offline storage, but some high-res images can take a whole ZIP cartridge or more. Hard drive cartridges like the Iomega Jazz can hold GB's and are fast, but are expensive. CD-R and CD-RW writers are a good choice, since they have high capacities and low cost per megabyte. CD-R's can be read by most PC CD-ROM drives. CD-RW's can only be read by newer multi-spin drives. The main problem is that writing is slow. Tapes have the lowest cost per megabyte and highest capacity, but random access is slow. They're best for backing up large hard drives.

JPEG Quality vs. Compression

Scan size: 5.89" X 3.96" (4 X 6 photo)
DPI: 21
BMP size: 122,894 bytes
Color: 24-bit
Pixels: 246 X 166

JPEG Quality vs. File Size

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Examples of JPEGs at Different Quality Levels

JPEG at 75% quality, 11,559 bytes
This looks virtually identical to the original BMP file, but is much smaller. 75" quality is a safe compromise between quality and compression for most images.

JPEG at 55% quality, 8,053 bytes
This still looks acceptable, but some artifacts can be seen in the hills at the left and along the horizon. Some of the details are starting to get blurry. You can get away with this level of compression if you have an image with large details, or where distortions in the detail are not apparent, such as in pictures of trees or grass. Also, you shouldn't have detailed areas next to solid-color areas or else you'll see color artifacts in the solid areas.

JPEG at 25% quality, 4,475 bytes
The details along the horizon and left side are very blurry. Detail is lost on the hills. The sky shows some blockiness on the right side. It's marginally acceptable, and the high degree of compression may be more important than the quality.

JPEG at 15% quality, 3,113 bytes
This looks a view through a wet window. Much detail is lost. The sky is severely blocky, with many color artifacts. This is probably unacceptable for this image, but there may be some images where this level of quality works. The only way to tell is try it and see.

My Space-Squeezing Experience

Zooming In

The raw image was somewhat blurry, so I sharpened it up with PhotoImpact. The sharpening process enhances the edges of objetcts, but it also introduces some "noise" into the picture. The original photograph was taken with a $40 point-and-shoot camera on 35 mm film, processed at a discount store, so it's not the sharpest original in the world. I don't know if it's true, but I read somewhere that mass market photofinishers tend to print negatives slightly out of focus to hide dust, grain, and scratches. This means that if you scan these prints at high resolution, they'll be blurry. For maximum resolution and quality, dedicated negative scanners are the best, but that's only necessary if you're a very serious user or a graphics arts professional. The point is that if you're using the scanner for Web images, you don't need very much resolution. Even the cheapest scanners are adequate.

Reliability Considerations

I would guess, based on the inherent design differences between sheet-fed and flatbed scanners, that flatbeds are more reliable. The sheet-feds have to handle paper and are more prone to jamming, just like printers. Paper tends to shed particles, which can clog the mechanics or dirty the optics. Dust and other contaminants can get into the innards of a sheet-fed more easily than a flatbed, which tends to be sealed up. It's like the difference between a floppy disk drive and hard disk drive.

The component most likely to go out first is the scanner's lamp. Many scanners, like my E3, use a standard fluorescent lamp that stays on all the time to stabilize its color temperature. Other scanners use cold cathode lamps that have 10,000 hour lives, which is probably beyond the useful life of the scanner. On the other hand, even though standard fluorescent lamps don't last as long as cold cathode lamps, they are cheap to replace, about $5.

Scanner Recommendations 

• Primary Usage--determines type of scanner and resolution
• Price range
• Scan resolution, bit depth
• Scanning speed
• Ease of setup
• Portability, size, weight
• Scan area
• Bundled software
• Software compatibility
• Accessories (document feeders, slide adapters, etc.)
• Durability, reliability
• Warranty, service policy
• Manufacturer's reputation

Type of Scanner

Most flatbed and sheetfed scanners use CCD (charge-coupled device) arrays with a system of mirrors and lenses to project the scanned image onto the array. A recent innovation that does away with the mirrors and lenses is the CIS (contact image sensor). CIS uses a long, thin array of sensor elements next to a row of color LEDs that provide a light source. The advantage of the CIS technology is that it allows the scanner to be very thin and light. It also uses less power, which can allow these to be powered by batteries or by the power from the USB port. As with any new technology, it is going through some growing pains, so the image quality is still inferior to traditional CCD designs. This may change in the future. For most home and office uses, the space-saving (vertical height, not desk area) and the lower power is not a big deal, so there's no desperate need for this technology.  See "CCD vs. CIS - Where the New Technolofy Hits--and Misses."

If you're a serious film photographer and want the ultimate in picture quality for print publishing, get a film scanner. Unfortunately, they're much more expensive than flatbeds and are much more specialized. The professional-level ones are over $1000, but the prices are coming down to the point where lower-priced models are affordable by serious amateurs. They are still not quite mass-market yet (and it's uncertain if they will ever be), so you don't see as many new models or such intense price competition as in the flatbed market. HP has one, the Photosmart, that is geared towards high-end consumers and is priced below $500. It can handle not only slides and negatives, but color prints up to 5X7. Other big players in this arena are the traditional camera companies, like Kodak, Nikon, Minolta, Polaroid, Konica, and Olympus. All have models above and below $1000. Microtek's ScanMaker 35T Plus is the venerable scanner manufacturer's slide scanner. (See the Scanner Manufacters links below.) Color slides have tremendous dynamic range, much more so than prints. You need a good film scanner, preferably with 30-bits or more bit depth to capture and take advantage of that dynamic range. Since film scanners are aimed at  professionals or serious amateurs, performance is more important than ease of setup. That's why these scanners mostly have SCSI interfaces.
 

Interface

SCSI scanners may come with their own SCSI card. My E3, for instance, came with a low-end Adaptec SCSI card that only officially supports one device. Other SCSI scanners require you to provide your own SCSI card. SCSI cards can cost as little as $50 for a low-end model, to >$200 for high-end cards. Some scanners have their own proprietory AT-bus interface cards; some are plug-n-play. In any case, unless you already have a SCSI card installed, you need to open up your PC, which can be a pain for some users. SCSI cards also require a precious interrupt, which may not be available if you already have a lot of peripherals on the system (not that the archaic PC architecture has a lot of interrupts to spare - don't get me started on a diatribe about this).

There are many different kinds and price ranges of SCSI interface cards. The cards that are typically bundled with low-cost scanners are very simple cards that are intended to be used only with the scanner. They run in programmed I/O mode, which means the CPU has to get involved with each bye of data transferred. The Adaptec card that came with my Microtek E3 is one such card. While scanning, it totally ties up the CPU, so all other processes are frozen. For more money, you can get a general-purpose bus-mastering SCSI interface card that will not tie up the CPU as much while scanning. It can also interface with more than one device. This is an advantage. If you can spare an interrupt to install the SCSI card, you can plug multiple devices into that SCSI card and only use that one interrupt. However, SCSI peripherals can be tricky to set up. There are several flavors of SCSI (SCSI-1, SCSI-2, Ultra-SCSI, wide SCSI, etc.), so you can run into complications if you try to drive different types of SCSI types from the same card. Different types of SCSI use different connectors, which are not compatible. There are adapters available to convert from one type to another (e.g. 68-pin to 50-pin), but they tend to be expensive.  SCSI also has cable-length limitations and termination requirements that you have to keep in mind.

If you already have an interrupt allocated for the parallel port, you don't need another interrupt to run the parallel port scanner. These scanners have pass-through connectors so you can hook up your printer to the same port. If you also have a parallel-port Zip drive, you could (theoretically), daisy-chain all three. However, this can have compatibility problems, particularly with the printer. You could use a switch box, but that can also cause problems, depending on how picky your printer is about signal quality. You also have to remember to manually set the switch box to the right position. Like SCSI, the parallel interface has cable length limitations, but they are less well-defined than SCSI. Usually, it's the printer that's the pickiest about the cabling. See "SCSI or Parallel?" by Graeme Bennett.

The easiest interface solution, in my opinion, is the new Universal Serial Bus (USB). This bus is found on most new computers and is supported by Windows 98. It's not as fast as SCSI, at 12 million bits/sec, but it's much easier to set up and is faster than most parallel ports. It's also much more expandable. Theoretically, you could hook 127 USB devices on the same bus, not that you'd want to or could afford to. USB connectors are smaller and easier to hook up than parallel port or SCSI cables. They are also thinner and can be longer. The USB port provides power to low-powered peripherals like joysticks. Most scanners use too much power to be powered from the USB port, but with the new low-powered CIS technology, this may change. USB is relatively new, but more and more peripherals are coming out with it. A USB scanner would be my choice if I had a new PC and needed a new scanner. If you have an old PC and don't have built-in USB ports, you can add a USB card. Newer Macs, like the iMac, also have USB ports. If you have a Mac, you need to make sure the software that comes with the scanner supports it.

You have to decide on what your priorities are and read the reviews and manufacturers' specs to see how different scanners compare in each of these factors. See the links below to go to those specs and reviews. Unless you have limited specialized applications, the best type of scanner to get is a flatbed. It's the most versatile, but it does take a lot of space. Personally, I like my Scanmaker E3. It works great. The software bundle is very good, especially PhotoImpact. I haven't yet had a need for a higher optical resolution than 300 DPI, but my HP660C printer is limited to 300 DPI. However, the E3 is not state of the art anymore. For a few dollars more, you can get a 600 X 300 scanner by several companies. 600 X 600 and even 600 X 1200 scanners for reasonable prices are becoming more common.

Scanner Information and Reviews 

• Welcome to the DPI Electronic Imaging WWW Site! This is by far the best site I've seen on scanners. It links to many sites, including Wayne Fulton's scanning tips, mentioned in the Introduction. His tips link to many scanner reviews.
• Scanning Photographs Good scanning advice from Photodex.
• FamilyTested Hardware: Scanners Top rated: HP Scanjet 5PSE, best buy: Microtek Scanmaker V300, 11/97.
• How to Buy Flatbed Scanners: Introduction. Recommended: Microtek Scanmaker E3 for value, HP Scanjet 5PSE for performance.
• Umax Astra 300P Color Flatbed Scanner
• Scanning from a Flatbed Review of Microtek Scanmaker E3
• Scanning Tips from Jasc Software
• Affordable Flatbed Scanner Summary 12/96 "If ultra high quality is imperative, we would choose the Agfa StudioStar with full Photoshop. If you're on a budget, go with the Pacific Image Electronics ScanAce."
• ZDNet Tech Review: Scanners Reviews Opticpro 4800P, Microtek Scanmaker E6, HP Scanjet 4C.
• Review: Info Peripherals ImageReader FB Flatbed Color Scanner, $330 street, PC Magazine, 3/4/97
• How To Buy A ...Flatbed Scanner - August 1997
• Scanner Has a Billion Pluses - August 1997: Plustek OpticPro 9630P 30-bit color flatbed scanner
• HP Network ScanJet 5 - August 1997
• Tricks, Tips and Techniques for Superior Scanning - August 1997
• Prices Fall, Quality Soars on Desktop Scanners (2/7/97)
• Features: Scanners for the Rest of Us (1/97) "Among flatbed models, the Hewlett-Packard ScanJet 4P won out..for a sheetfed scanner...Storm Technology EasyPhoto SmartPage"
• How Low Can They Go? Color Scanner Prices in a Free Fall (5/22/97)
• Computer Shopper: Microtek ScanMaker E3 (6/96)
• Capture the Color PC Magazine March '97. Recommends: Mainstream business and SOHO/home users: UMAX Vista-S12. Graphics professionals: Microtek ScanMaker III.
• When a Flatbed Scanner Is Too Much (Sheetfed scanners, March 1997)
• Flatbed Scanners: Reviews At A Glance Links to reviews of 10 scanners
• Fortune | Technology Buyers Guide (updated periodically)
• Computer Life: HP ScanJet 4p (May 1996)
• PC Computing: HPScanJet 4p (April 1996)
• Computer Shopper: Mustek Paragon 800 SP (June 1996)
• High-Resolution Scanning PC Today Processor - HP Vs. Microtek Vs. Agfa Vs. Pacific Image Electronics Vs. Mustek Vs. Ricoh
• Scan Perfect: Benchmarks Results of testing 11 scanners, June 1996
• Mustek Frequently Asked Questions
• 11/24/97 SCANNERS THAT FIT YOUR DESK--AND YOUR BUDGET "if you have room--try a flatbed scanner, such as UMAX Technologies Inc.'s new Astra 610S for $149 or Optic Pro 9630P from PlusTek, for $149. We also recommend HP's $299 ScanJet 5p."
• Yahoo! - Computer Buyer's Guide Top Sellers: Scanners
• How to Get the Most out of Your Scanner by Caere Corporation
• SOHO Scanners - PC Magazine 11/4/97
• Value-Minded Flatbeds - PC Magazine 11/4/97  "The $250 Visioneer PaperPort 6000, our Editors' Choice in this roundup, had the best combination of software and performance."
• ScannerUser: Tips & Tricks -- ZDNet Products
• Agfa Scanning Publications

New Links

• ScannerUser: Desktop Scanners -- ZDNet Products Links to scanner reviews 12/18/98
• Make a Connection with USB -- ZDNet Products 1/6/99
• Stump Jeff: Adding USB Ports To PCs And Macs (12/23/98)
• 28 Scanners: Cheaper, Smaller, Better -- ZDProducts 1/25/99
• Small Business Advisor - Buying Scanners for Your Business
• Instant Image: Digital Camera, Scanner, & Printer Superguide -- ZDNet Products 10/21/98
• Scanner Section Index by Graeme Bennett
• More Scanning Solutions by Graeme Bennett, 1/5/99
• Scanner Q&A by Graeme Bennett 10/27/98
• Review: ScanAce 1236s Macworld 7/98
• PPN: Review: Artec ViewStation AS6E 3/98
• ZDNet Scanner Reviews
• ZDNet: Artec ViewStation AM12E 1/25/99
• Visioneer PaperPort One Touch 5300 1/11/99
• Review: StudioStar 6/17/98
• PC Magazine: Desktop Scanners - 10/20/98
• Buyer's Checklist - Scanners - Computer Shopper
• Scanners for Your Business - ZDNet Small Business Advisor
• Getting Pictures into Your Computer - ZDNET 8/26/98
• Camera equipment and Scanners Review - A FLAAR Website
• TechWeb Scanners & Input Devices - reviews, specs, prices, comparisons, and ratings
• The PC Technology Guide - Scanners
• DIGITIZATION: A Literature Review and Summary of Technical Processes, Applications and Issues
• Professional Presence Network - Reviews
• Xerox DocuImage 620S
• USB Central
• WebShopper Scanners Roundup 6/8/98
• PrePRESS Technology Report - Scanners, Digital Cameras, and Photo CDs

Film Scanner Information

•  HP Photosmart Photo Scanners
• Digital Scanner Reviews: HP Photosmart, Nikon LS-2000, Olympus ES-10 film scanners
• CNET Reviews - Just In - Hewlett-Packard PhotoSmart PC Photography System
• Tony Sleep - Home Page (see section on film scanners)
• More Scanning Solutions - HP Photosmart Scanner
• Nikon Slide Scanner (Cameras Scanners.org)
• Graphic Arts: Nikon updates Coolscan 3/19/98
• Slide-Scanner Spectrum Macworld Magazine 12/95
• Olympus's High-Quality Slide Scanner (PC World Online 1/98)
• Photo.Net: Slide Scanners

OCR Software 

The process of optical character recognition is not an easy job. It requires a tremendous amount of computer power, and it's only with the more powerful processors like Pentiums has it become practical for home computer use. If you consider all the thousands of fonts that are available, in all different sizes and spacing, the OCR program has to be very flexible to be able to recognize them. Some characters are very difficult to tell apart, such as 1, I, l, 0, O, and o, especially with mixed fonts of different sizes. The better OCR programs can be "trained" to improve recognition quality, especially with unusual fonts. The quality of the original is alsoimportant for accurate scanning. Dirt or smudges on the original, or copies with blurry or broken letters are also difficult to scan. Decimal points can get lost if they're too small, or spots can appear as periods in the wrong place.

The hardware requirements for good OCR work is not too demanding. The scan resolution required depends on the size of the text. The smallest font size that can be scanned effectively is usually around 6 points. At this size, you need to scan it at 300-400 DPI. For bigger fonts, you can and should scan at a lower resolution. Over-scanning doesn't help and can even hurt. The OCR program has to sift through all that scan data to recognize the characters. No use overloading it with unnecessary samples. Normally, documents are scanned as line art.

The accuracy of the OCR process is mostly dependent on the software. There are many OCR programs. Most scanners come bundled with one. The OCR software bundled with lower-end scanners are often simpler versions or out-of-date versions of full-featured OCR packages. Which is the best OCR program? New programs and updates appear regularly, so the situation changes constantly. In general, Caere's Omnipage and Xerox's Textbridge have gotten the best ratings. A lite and old version of Omnipage came with my Scanmaker E3. It does a good job on text in the 10-point range. However, when I tried it on 6-point type, it made a lot of errors. I didn't try optimizing it, however. I later tried the latest and greatest version of Xerox's Textbridge (on a UMAX 600P scanner) with the default setup, and it read the same text with few errors. Many OCR programs, including Textbridge, allow for training the OCR to improve its accuracy. An OCR program can be setup to feed text directly into a word processor. It can appear as a menu item in the File menu of a word processor.

• Caere scanner ocr software
• Company Index - Software FAX/ OCR & Document Imaging WINDOWS
• NeuroWeb: Home of NeuroTalker OCR
• Ligature
• Voting OCR Software from PRIME RECOGNITION that is 65-80% more accurate than conventional OCR. OCR for Free at www.primerecognition.com
• Speed Reading OCR Software
• Xerox Scanning Solutions
• OCR Software - PC Magazine Online 1/20/98
• Benchin' - Business - Optical Character Recognition
• Review of Cuneiform 3.1 - Sharepaper.com
• Review of Omnipage Pro 9 - Windows Magazine Feb. 1999
• OCR Software - House of Scanning
• Pagis Awards & Reviews - Xerox Scansoft
• Book: OCR With a Smile - House of Scanning 7/24/98
• Yahoo - Character Recognition (OCR/ICR)
• OCR 70,000 Pages per Week at 99.985+ Accuracy
• From Books to the Web - The On-line OCR Lab - 1997 to 1998
• ScanFix image enhancement software
• Universal OCR v3.0 98 - teaches your scanner to read and type 33 languages!
• OmniPage Pro 7.0 - Web Developer's Journal
• OmniPage Pro 8.0 A Software Review by Tom Richardson Member of the Sarasota Personal Computer Users Group, Inc.
• LEON PERLMAN explains how "optical  character recognition" can cut out tedious re-typing
• Language Force Universal OCR, converts text files in 33 foreign languages
• Intelliscan Document Management Systems
• Cognitive Technology Corporation - Cuneiform
• Del Mar Data - Document Conversion Experts

Image Editing Software 

• Lightening, darkening the image.
• Adjusting the contrast.
• Sharpening, softening the image.
• Changing the color balance.
• Changing the dimensions and resolution of an image.
• Rotating or distorting an image or other special effects.
• Cloning: copying one portion of an image to another. This is a powerful tool for image editing, such as removing unwanted details.
• Combining multiple objects, including text, onto one image.
• Using "paint" tools to retouch the image.
• Erasing parts of the image, "bluescreen" effects.
• Removing "moire" effects--patterns that can appear when scanning halftoned images from printed materials.
• Adding frames or fancy edges.
• Converting and saving the image to different file formats.
• For more information on how to use some of these features to improve scan quality, see A few scanning tips - A Simple Way to Get Better Scans>

Image Editing Software Links 

• Adobe Systems Incorporated
• Alchemy Mindworks Inc.
• Corel Corporation Homepage
• Digital Workshop Web Site
• Fractal Design Online
• Welcome To G&A Imaging Ltd.
• Graphics :Picture Viewers and Editors
• Dreamscape Reviews: Hijaak Pro
• Image Editing Software Mini Reviews
• Inter Dimensions: gifx -- GIF Animation Magic
• Welcome to the Home of Jasc, Inc.
• LivePix
• MetaCreations Corporation
• MGI Software Corporation
• Microsoft Picture It! Home Page
• CNET reviews - just in - Picture It 2.0
• NewSoft, Inc Main Page
• Photodex - Graphics Utility/Management Software & Free Graphics Tutorial
• Pixel Translations - ISIS® Products
• Polaroid Software
• ScanTastic Sales Literature
• Stroud's Graphics Viewer Reviews
• Ulead Systems Innovative Multimedia Solutions
• CNET reviews - just in - PhotoImpact 3.01 with WebExtensions
• Lawrence Gozum's Page (at AOL): VidFun
• Yahoo! - Computers and Internet:Software:Reviews:Titles:Graphics:Photo Editing

Scanner Manufacturers 

• A Buyer's Guide to Desktop Scanner: Companies
• Acer Peripherals Scanners
• Welcome to Adara Technology
• Agfa Scanner Product Family Overview
• Artec/Ultima International
• Avision Product Information
• Bell & Howell Scanner Division
• Canon Computer Systems Inc.
• Epson Digital Cameras and Scanners
• Fujitsu Scanners
• HP Printers and Digital Imaging
• Howtek
• IBM Announces Color Flatbed Scanner
• IBM Accessories Ideascan Color Flatbed Scanner
• Imacon
• Info Peripherals - Scanners
• Kodak Scanners
• Konica Digital Scanners
• LinoColor
• Logitech
• Memorex Scanners
• Microtek Home Page
• Minolta Scanners
• Mustek
• Welcome To Nikon Inc.
• Olympus Scanners
• Pacific Image Electronics Home Page
• Plustek USA
• Polaroid Scanners
• Relisys scanners
• Scanport Home Page
• Tamarack Technologies
• Welcome to UMAX
• Verbatim SS600 Storage Scanner
• Visioneer

Computer Art, Graphics, and Photography 

• Artistry online
• CSS: AIIM - Association for Information and Image Management
• Scanned photographs of various bands and artists
• UCR/California Museum of Photography
• California Views: The Pat Hathaway Photo Collection
• the gallery BY simon chow
• City Gallery (History of Photography)
• Digital Imaging Center Information
• Digital Photography Exhibit
• FileFormats.faq
• Ford Library Photo Collection
• Fondation Select
• J. Trant, Framing the Picture: Standards for Imaging Systems
• Getty Information Institute: Introduction to Imaging
• The Graphics File Format Page
• HyperZine: The Online Imaging Resource
• LensWork Home Page
• Library of Congress: Photographs, Prints & Drawings
• The Media History Project
• National Museum of American Art
• National Press Photographers Online
• KODAK: Photo CD Technical Papers
• PhotoGen FAQ Volume 1
• Photography Collection
• ONLINE PHOTOGRAPHY-Fine art photography-Terry Staler
• PEI Magazine
• Welcome to PhotoWeb
• Preparing Quality Images for Computer Networks: Table of Contents
• QBIC Home Page
• JWS - Goshen Cove, Scanned photographs
• Digital Camera Alternatives?

Retailers and Distributors 

• Armorware: A wholesale shop specializing in laptops, Canon printers, scanners, and computer accessories.
• CDW
• Central Computer Systems - Application Software
• Welcome to CompUSA Direct Shopping
• Compulink Compushop - Top Ten - Scanners
• Compumart Home Page
• ComputerESP Search
• Welcome to Computer Graphics Technology!
• Computown: Scanning Devices
• Digital Darkroom from Ted Pella, Inc.
• Electroweb: Scanners, Modems and More
• Envisions Online
• Graphtronix
• Hi-Tech USA: SCANNERS
• All LCD projectors, presentation products & support materials for presentations - Presenting Solutions
• Outpost.com
• Provantage
• PSI's Color Scanners for Desktops and Notebooks
• QCI Products - Scanners
• The Scanner Guys WEB Page
• Tech Shopper: Scanners & Input Devices
• Bob Weber Homepage for Scanner, agfa, Linotype, RIP, Harlequin (Professional scanners)
• Publishing Perfection
• Primary Simulation, Inc.
• ScanHelp.com - The Scanning Software Site
• Cavin's Document Imaging Division

1999 Update Note:

Recent hardware innovations that have popped up since the last update are the Universal Serial Bus interface and the Contact Image Sensor (CIS) technology, which I discuss above. I also got a new computer with a USB bus, but I haven't seen any reason to replace my good old reliable SCSI Microtek S3 with a hot new USB model.

I also added some more information about film scanners. I checked and deleted some of the dead links in the reviews links, but kept some of the old ones since some of the information is still valid, if not the prices. I updated the manufacturers links. Some manufacturers (like Storm recently) have died or changed names. New ones have popped up. The old reliable brands (HP, Microtek, Umax, and Mustek) are still plugging along. I added a few new retailers. I haven't gotten around to checking all the other links, so if there are a few dead ones, I'll prune them out later.

I admit that when I first created this page, I went overboard on animated GIFs and horizontal rules, and it's way too long. If I ever get time, I'll re-design and re-organize this page. I'm still dabbling with Web page styles. To see one of my latest pages, go to Bay Area Biking or the even more recent North Coast and Redwood Empire pages.

Click here to go to Ron Horii's Bay Area Back Pages (lots of scanned photos)

Previous version 12/11/97. Latest Update 3/10/99