8.10.1: Large format image display and hardware for DEIMOS

The graphics interfaces for all of the options discussed below have servers for the X Window System. Use of a dedicated image display without X could result in better performance, but the costs of creating non-interoperable software for unique hardware do not justify such an effort. The X Window System has advantages of portability, interoperability, and familiarity. DEIMOS image display will use the X Window System.

DEIMOS direct images will be roughly 8k x 3k pixels. DEIMOS spectral images will be 8k x 8k pixels, although it seems likely that these will be stored as four 2k x 8k images. These images are larger than the pixel resolution of all existing monitors. During typical operation at the summit there could be a desire to display two DEIMOS images with one as quick-look and another for reduction.

Commonly available high resolution monitors for computers have no more than 1280 x 1024 pixels. This implies binning by a factor of 8 to display an entire image. Commercial availability of HDTV will not solve this problem because its vertical resolution does not exceed currently available monitors. The advantages and costs of various possibilities are described below. 2k x 2k Monitors

2k x 2k monitors are currently a specialty item used only in a few air traffic control and satellite imaging operations. These monitors require hardware interface cards to the CPU and X server software tailored for that hardware. (One vendor supplies a complete hardware solution that plugs directly into an s-bus slot of a Sun or a u-channel slot on IBM. Others provide frame buffer cards intended to fit in a separate 6U VME chassis.)
	    item                                 cost
	1 2k x 2k monitor                       $32000
	1 graphics interface card + SW          $5000 - $10000
	1 keyboard & mouse                      counter top space
	1 bus slot  [optionally]
  [or]  1 6U VME chassis with CPU               $$$$
A few systems exist where these 2k x 2k monitors have been arrayed into a video wall of 4k x 4k pixels. However the costs of such a system are beyond the DEIMOS budget. It is unlikely that spare hardware components could be purchased, so this system would be unique. Arrays of commonplace monitors

X server software which can drive multiple screens as a single display is freely available for Sun platforms and commercially from Quadrate and X/software for several other brands of CPU. A desktop Sun system can accommodate up to 4 additional graphics S-bus cards. These could be stacked into a 2x2 video wall with the original console at the side. This arrangement provides a display surface of 2560x2048 pixels plus the original console. The price of such a video wall would be less than for a single 2k x 2k monitor, but it would effectively consume an entire machine.

There are various possible configurations for such monitors. A workstation's original monitor could be supplemented by 4 more to give an image interaction array plus a console; or by only 3 screens to produce a 2x2 array; or simply add one extra monitor and bin by a factor of 8.

	N 19-inch hi-res color monitors         $2500 each
	N graphics interface cards              $800 each
	N bus slots
	N times 2 Mbytes of memory              $80 each
	  software license from vendor          $1000 Analysis

Even the best conceivable hardware would still require binning of the image and interaction with more than one window. For this reason the software for image display and interaction should make it easy to place a full frame image in one window and a zoomed image in another window. It should be possible to place different windows on different X screens or even on different X servers. This will permit operation of the software with any configuration of color X hardware.
Steve Allen <sla@ucolick.org>
$Date: 1996/03/18 23:40:21 $