dave@onfcanim.UUCP (09/21/86)
Some additional info on Jon's info: In article <266@msunix.UUCP> jon@msunix.UUCP writes: >> [me:] >> If you want to do input at video resolution, you just need a good >> video camera and a frame grabber. But to work at 2048 or 4096 pixels, >> about the only thing available is an Eikonix scanner that will cost you >> at least $30K. > >Someone is selling a video camera that does 2600 x 2048 for about >$30K also, if you need a camera instead of a scanner. I can't >recall the company's name. I was under the impression the Eikonix >scanner was much more expensive. For that price, people wouldn't >mind taking a picture of the image they want to scan in, then scan >the film on the scanner. The Eikonix isn't a film scanner, it's configured as a camera. It has a lens, which you normally point at the base of a copystand, but you could just as well aim it across the room. Of course, you can digitize film too with an appropriate light source. The imaging element in it is a linear photodiode or CCD array (depending on model) that is mechanically scanned across the aperture, making three passes in the case of colour digitization. Thus the name "scanner" seems more appropriate than "camera", even though it could be used to digitize anything that can stand perfectly still for several minutes. If you want faster digitization, you need a camera. But be careful - cameras that use CRT's suffer from non-linearity of the sweep across the tube, and are not absolutely accurate geometrically. The Eikonix geometric accuracy is about 1/2 pixel across the whole image. And yes, the Eikonix is around $30K US, depending on whether you get an optical viewfinder, buy their copystand, get long-line cables, and so on. (We're in the process of buying one, so I have the prices here.) One model gives 2K spatial resolution and 12 bits of intensity (good enough for the full luminance range of film), another gives 4K spatial resolution but only 8 bits of intensity. There is a third, low-cost model that is B&W only and intended specifically for use with PC's and the like. >Jim Dunn of Dunn Instruments in San Rafael, CA builds an 8K x 8K >film recorder also. I have seen some 8 x 10 transparencies from it, and >to my untrained eye, it looked pretty good. From talking to Jim >Dunn, it sounds like this film recorder is a real screamer. His literature >mentions a "proprietary bicubic interpolation scheme" for interpolating >any size input up to the full 8K x 8K resolution of the tube. This is a great idea when you are producing a bunch of single slides coming from a variety of sources at various resolutions. With almost any other film recorder, you'd have to use your own software to change the resolution of each images to whatever the "standard" resolution of your film recorder was. This is an advantage over fixed-resolution recorders like the Imapro/Matrix QCR. However, it isn't *always* what you want. The Dunn always takes a long time to plot a frame (4 minutes plus, if I remember correctly) because it's actually plotting 190 million individual pixels. For long runs of images that are all at the same resolution (e.g. animation), you want a film recorder that can be configured to work directly in the resolution you are using. For example, our Celco will plot at least at the resolution of the Dunn if we wanted it to, but we currently have it set up to plot 1024x768, and it does a frame in about 15 seconds at that resolution (on film with an effective ASA of 64). The Dicomed has a "programmable pixel format" that should give you some of the same flexibility in number of pixels in an image without the analog adjustments required to change resolution on the Celco. Also, be careful about confusing the "resolution" of positioning the beam on the tube face with the "resolution", in optics terms, of the resulting image. The best example of this is the Dicomed, which has at least 32Kx32K beam positioning resolution (in order to draw smooth vectors). However, its CRT spot size is .001 inches, and with a 5 inch (diagonal) tube, you can't expect to get more than about 4000 lines that are clearly resolved in a raster image. Celco claims a bit better for its recorder, with a .0008 spot size (varying with brightness) and a 7 inch tube. I've been told that the Dunn uses a CRT with a spot size of about .002, so it would be capable of even fewer clearly-resolved lines, regardless of 8000x8000 pixels being plotted. For a CRT output device, the CRT spot size divided into the CRT face dimension gives an absolute limit on real resolution. For a laser scanner, much smaller spot sizes are possible and the dimensions of the image are limited only by the size of the film you can mount. Dave Martindale