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Phil Hobbs

Contex’ FSS 8300-PLUS DSP is an 800dpi monochrome, A0 scanner. It is a full-scale scanner, which refers to its ability to scan documents right up to A0 in size, and features Contex’ Area Diffusion Logic technology—designed to maintain image integrity while keeping file sizes compact.

Using a stabilized fluorescent lamp and dual CCD sensors, for a total of 16,000 scanning pixels, it allows a maximum scan width of 914mm (36") and unlimited scan length. Feedable document widths are from 152mm (6") to 1016mm (40"). Interfacing with the host computer (which can run Windows 95/NT or UNIX) is by a standard SCSI-2 connection.

The FSS 8300-PLUS DSP is designed as a high-volume workhorse and has physical dimensions of 1200 x 200 x 380mm (W x H x D), plus the optional stand.

After assembly, the first task in getting the Contex FSS 8300-PLUS DSP scanner up and running is to install the SCSI adapter board supplied into an empty slot in the PC. The board is an Adaptec with easy-to-follow software installation. I did not use the adapter board supplied, as I already had an Adaptec AVA-1505 installed. This worked fine.

The software supplied with the FSS 8300-PLUS is CADImage/SCAN, a program designed to interface the scanner with a wide range of software for CAD, desktop publishing, drawing archival and faxing. It also allows easy conversion between more than forty standard industry image file formats.  Using the copy feature in CADImage/SCAN with the Contex and a laser printer, it is an easy task to transform large-format drawings into a handy size for inclusion in a technical document or reports. You can, of course, make a full-size copy using any large-format plotter that can handle raster files.

I installed the CADImage/SCAN software on a PC with Windows 95 as the operating system: a typical wizard install in which I followed the prompts and all worked without problems. Any reasonably powered CAD workstation (Pentium 200+) will do just fine as the host.

After turning off the PC and connecting the SCSI cable, I fired up the computer again, the drivers loaded automatically and I started CADImage/SCAN.

The first task is to align the CCD cameras (adjust their height). To aid this a height alignment chart is supplied. Insertion of a thin screwdriver through a hole on the top of the scanner provides the adjustment that lines up the left and right cameras. I have found with our bureau’s other two scanners (also Contex models: an FSS 8000 and FSS 5000) that realignment need only be repeated when the scanner is moved. We still check it once or twice a year. The only other maintenance needed is regular cleaning of the scanning area.

When you start up CADImage/SCAN, you will see the main menus from which you can start the operation station screens: File, Scan, Convert, Print and View. The Scanner Setup choice in the File menu allows you to select the active scanner and your load method and to fine-adjust the scanner’s vertical precision setting. Also in the File menu there are the usual Save Settings On Exit, Save Settings, Load Settings and Exit.

To start scanning select Scan from the main menu and you will be presented with the Scanning Station screen. From here you can directly control all aspects of scanning a drawing. The scanning station screen is divided into five major areas: Filename and Scanwidth; Info; Detail and Overview Windows; Scanning Control Panel; and Scanning Options. I’ll cover the first four areas briefly and Scanning Options in more detail, as it is where the features of the scanner and software are exploited.

Filename and Scanwidth are destination fields which must be set before starting the scan/prescan, as they cannot be changed on the fly. The Info button pops up a window showing drawing width and length in pixels, resolution and size of the previously scanned file. In the middle of the scanning station are the detail window and the smaller overview window, both of which are active during prescanning or scanning. When scanning to file, clicking the mouse in the overview window moves the zoom-in view along the horizontal line of scanning. The Scanning control panel controls scanning and prescanning operations and threshold settings.

Scanning options: Setting the basic scanning options for the FSS is done by clicking on the corresponding buttons in the bottom line of the Scanning Station screen. Options are:

Type: Select the destination file format type.

DPI: Set resolution to a maximum of 800dpi. 300dpi is usually the maximum I use.

Mode:

Line – Uses threshold to determine if a pixel is black or white; used for drawings or line art;

Graytones – In this mode, 256 gray levels are recognized for each pixel;

Dither – Scans graytones as high-resolution, dithered black and white.

Proc [processing]:

Dynamic - The scanner analyses the information in the drawing and detects and emphasizes edges, fine lines and small details. This option is most useful with drawings that have poor contrast or weak definition;

Enhanced – Lines thinner than one pixel are increased to one pixel width. All other lines are increased by one pixel;

Dynamic+Enhanced – Both of the above.

Spck [speckle]: Despeckles on the fly by removing speckles fitting within a square of definable size.

Auto:

None – No auto selection (i.e., scanning in fixed-threshold or graytone mode). I found this to be best for batch runs, as I could select the threshold by prescanning a typical drawing and therefore had no holdups waiting for the software to determine the setting for each document. I suggest using the GL setting until you become more experienced;

Histogram – The scanner does an investigative scan of the original then returns it to the starting position. The image is analyzed and a histogram of the graytones displayed with a proposed threshold setting. You can accept or adjust this setting before final scanning. I found this method very time consuming;

GL-Global Autothreshold – Histogram analysis is performed as described above, but scanning to file proceeds automatically using the computed global threshold value;

Recall – Recall a previous histogram scan;

AN Adaptive Normal – For low-contrast and difficult-to-scan drawings. The scanner’s built-in digital signal processor (DSP) carries out two-dimensional, adaptive thresholding on the fly. Two controls, for adaptive level and background suppression, set the threshold for choosing data and the level of background darkness or patchiness to ignore;

AN Adaptive Normal Default – As above, but adaptive level and background suppression is set to default values for a normal drawing.

Special: Sets options for mirrored, reverse (negative) and rotated scanning, turns off the graphic display for improved speed, allows on-demand scans and enables automatic, incremental file naming for batch scans.

The online options of deskewing, despeckling and image rotation work fine but, if you have a large number of drawings to scan, you are better off performing these functions in a specialized program. I use Rasterex RxSpotlight to do it in a batch, so I can leave it cleaning up images overnight.

AutoCAD Release 14 can view raster files but, to edit the images, you will need a raster editing application. Rasterex RxSpotlight will perform standalone editing while Autodesk’s AutoCAD Overlay and Rasterex RxAutoImage Edit/Pro let you edit within AutoCAD. RxSpotlight Pro97 has the same functionality as RxAutoImage Pro 97. Images can be loaded automatically into Spotlight through Contex' TWAIN interface module. Also, RxAutoImage and RxSpotlight's intelligent raster entity-manipulation feature treats raster entities as "CAD-like" objects. Automatic raster-to-vector conversion can be easily done in seconds with either package inside AutoCAD or in standalone mode.

You can also use the Full Scale Scanner’s 256-level, greytone scanning with applications like AutoCAD Overlay to overlay satellite photos directly onto survey data in AutoCAD.

The Contex FSS 8300-PLUS DSP can scan A0 width at up to 800dpi and allows very high scanning speeds (up to 76mm/s at 400dpi). This, together with its robust construction, makes it an excellent choice as a production scanner for heavy-duty bureau use. It handled any originals I put into it, including some very ordinary originals in varying stages of disrepair and line quality, using the automatic feed. It autosenses input document size and, like the other Contex machines I have used over the last six years, was solid and simple to operate.

Phil Hobbs
CAD User - republished by arrangement

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