[Cyan]<CedarChest6.0>Documentation>DunnDoc.tioga!26

DunnDoc.tioga

Julian Gomez, September 14, 1983

Mark Chow, August 16, 1985

Jules Bloomenthal, March 27, 1986 12:29:08 pm PST

CEDAR 6.0 — FOR INTERNAL XEROX USE ONLY

Dunn

a programming interface and computer tool for the Dunn camera

Jules Bloomenthal

Abstract: Dunn is a package of software callable procedures and user programs to provide software control of the Dunn Instruments 632 film recorder. This film recorder uses a high quality internal monitor to expose each color primary separately for maximal color presentation. 35mm recording is done with a Yashica camera, 16mm with a Bolex. The quality of the recorded images is sufficient for presentation to large audiences.

Keywords: Dunn, animation, film recorder, camera

XEROX Xerox Corporation
Palo Alto Research Center
3333 Coyote Hill Road
Palo Alto, California 94304

For Internal Xerox Use Only

Software Environment

Bringover -p /CedarCedarChest6.0/Top/Dunn.df.

For programming, refer to Dunn.mesa and DunnCommands.mesa for procedure descriptions.

Program Synopses

The following programs are registered in the ///Commands directory:

DunnSnap <color-ais-root-name, full-ais-name, or interpress name>

DunnView <color-ais-root-name, full-ais-name, or interpress name>

DunnTool [command] [argument]

DunnSnap

DunnSnap displays and photographs an image using the Dunn camera; usually this program is run on Reprisal.

The images displayed are without scroll bars or captions. The color display monitor should be set for 1024 by 768 resolution, as described below. Images larger than this resolution will be clipped; images smaller than this will be bordered by black.

If the argument to DunnSnap is the root of a color AIS triplet or the name of a color Interpress file, the red, green, and blue components are sequentially displayed and photographed before the film is advanced; otherwise a single grayscale image is displayed and photographed. All images are rapidly displayed if the file(s) are local.

DunnView

DunnView displays an image without actual use of the Dunn camera; this program may be run on any Dorado with a high-resolution color display.

If the argument to DunnView is the root of a color AIS triplet or the name of a color Interpress file, the image is displayed via dithering; otherwise it is displayed as a grayscale image. Dithered images take some time to compute; the grayscale images are rapidly displayed if the file(s) are local.

DunnTool

DunnTool, if called without argument, creates a viewer with button-activated functions useful for user interaction. Alternately, the program may be called with a command line argument specifying the Dunn function; this is useful for operation via a command file. Case is unimportant when specifying command line arguments.

The following functions are available only as a command line argument to Dunn:

DebugOn Enable certain debugging features.

DebugOff Disable debugging features.

Reserve No command-line-specified operations are possible until the Dunn is reserved.

Quit Release the Dunn.

The following functions are available as a command line argument or via a viewer:

Disable Allow the software to function without using the Dunn hardware.

Enable Enable the Dunn hardware.

Expose Expose film either as a composite or not, depending on the exposure mode.
Expose film either as color or black-and-white, depending on the film type.

The exposure mode may be set by Separate or Composite.

The film type may be set by BW or Color.

Composite Set the exposure mode for composite. If film type is color, each command
to expose results in sequential red, green, and blue exposures before the
film is advanced. For high (1024 by 768) resolution pseudo-color images.

Separate Set the exposure mode to be separate. If film type is color, three exposure
commands (one for red, for green, and for blue) are required before the
film is advanced. For high (1024 by 768) resolution true-color images.

Color Set film type to color. Film will be exposed sequentially through
red, green, and blue filtered exposures with corresponding video.

BW Set film type to black and white. Each command to expose results in
a single exposure of the green video channel through a transparent filter.

Dub <integer> All exposures will be repeated integer times (the default is 1).

Reset Reset the filter wheel; set film type to color and exposure mode to composite.

Command <string> Transmit the command represented by string to the Dunn;
string must be a Dunn.cmdCode (see Dunn.mesa).

Examples

% dunn
% dunn expose
% dunn dub 5
% dunn command openAuxShutter

Error Messages

Various errors may result from attempted Dunn operations. Error messages are printed either in the commander viewer (if a command was typed) or the message window (if the command was initiated through the Dunn viewer).

When first attempting to use the Dunn, the following errors may occur:

Can't open Dunn, or Either the IO stream was not properly established or the Dunn status reported
Not opened, or an unopened condition, even though the IO stream was established.
IO error
Check that the Dunn is powered on.
Check that the Dicentra (located next to the scanner) displays a number
between 0.00 and 0.05. If it doesn't, and the Dicentra is not being used
for scanning, reboot the Dicentra with the front panel circular white button.

Dunn in use... Only one user may use the Dunn at a time.

In addition, any of the commands sent to the Dunn may fail, in which case a ``<command> failed'' message is printed.

Set Up

The Dunn Camera

The Dunn camera allows one to expose 35mm still or 16mm movie film to images displayed on a color monitor attached to a Dorado. The Dunn is usually configured with the 35mm camera. Other photographic accessories are kept in medium security storage. Please be careful when mounting or dismounting cameras. Always place lens caps on lenses as soon as practical, and put the cover over the hole in the top of the Dunn cabinet if there is a delay in mounting a camera. Please remember that all the photographic equipment in the installation is breakable or easily damaged.

The Dunn film camera views a high-resolution black and white monitor with a color filter-wheel between the monitor and camera lens. The internal monitor scans at a 1024 (wide) by 768 (high) pixel resolution. It will not scan correctly images sent at other resolutions.

Various software in the Cedar environment can produce pictures at varying resolutions; any image not at 1024 by 768 resolution, must be converted before being sent to the Dunn.

The Dunn camera is used principally in two ways. The first is to take pictures of 8 bit images displayed in black-and-white or psuedo-color. The second is to take pictures of 24 bit images displayed as a sequence of three black-and-white images.

Computer Set Up

The Dunn camera is presently attached to the Reprisal Dorado located in Room 2301G (in the CSL maze). A rollback of the Dorado may provide improved performance.

The Dorado color display resolution must be 1024 by 768, 8 bits. This is automatically set by DunnView or DunnSnap, but not by Dunn. To manually perform this:

1. Run ColorDisplay.
2. Right button ``Color'' in the herald window.
3. Verify that ``1024x768'' is in reverse video, or select it.
4. Set the number of bits to 8.

The above may be automated during login by setting the followings user profiles:

ColorDisplay.Type: conrac7211Hi
ColorDisplay.BitsPerPoint: 8

Video Set Up

The video connections to the Dunn are ``looped through'' from the Dorado color monitor; any signal that goes to the Dorado monitor is also sent to the Dunn camera. During an exposure, internal electronics displays one of the R, G, or B signals. Until the expose button is pushed, the Dunn monitor is electronically blanked, so that no image is seen through the camera viewfinder. Normally the internal Dunn controls and external video connections from the Dorado display do not require adjustment.

If the image sent to the Dunn is to be viewed on the Dorado color display, the display resolution must be 1024 by 768. To achieve this:

1. Turn display power off.
2. Remove the cover.
3. Change the position of the white Molex connector located on the vertical PC board (to the
left as one faces the tube face) so that there is one pin exposed above and one exposed below
the plastic of the connector. In ``low resolution'' mode, where most people run the monitor,
the connector is positioned so that there are two pins exposed above the connector.
4. Replace the cover.
5. Turn power on.
6. If the image fails to synchronize properly, check that the Dorado is set for 1024 by 768 display.
If the image still fails to synch, it may be necessary to adjust a trimpot internal to the display.
Please seek technical assistance.

35mm Still Pictures

In general, it is best to shoot a minimum of two copies of a given image; invariably slides are scratched, lost, or given away.

The following steps should be taken for all 35mm exposures:

Power on the Dunn. The 35mm camera should power on with the Dunn (a green LED should light); if it doesn't, use the switch located where the wind mechanism would normally be.

Verify the camera is loaded with film; this may be done by testing if the takeup reel spins freely (no film) or not (loaded). The film is loaded conventionally. Brian Tramontana (X4016) may be asked to provide and load film.

At the date of this writing, Ektachrome 200 is the preferred film (although 5247 may prove useful).

No focus adjustment should be made.

Settings

Unfortunately, a step wedge calibration to determine optimal f-stops for different film types has not been performed. F5.6 is suggested for Ektachrome 100; F11 for Ektachrome 200. F2.8 for Polarchrome (ASA 40). ``Bracketing'' the exposures is recommended.

Color calibration of the Dunn are not necessarily optimal; therefore do not expect precisely accurate colors.

8 Bit Images

An 8 bit image may be black-and-white, in which case black-and-white or color film may be used, or the image may be pseudo-color, in which case color film should be used. DunnSnap will automatically photograph a black-and-white image. The procedure may be manually performed with these steps:

1. Set the Dunn to normal (the default) mode (either via software or with the front panel switch).
2. Copy the 8 bit image into the Dorado frame buffer.
3. Expose the film (either via software or with the front panel switch). The camera will
automatically expose the three video components through red, green, and blue
filters, and advance the film. The camera is then ready for a new image.

24 Bit Images

24 bit images are real-color and color film should be used. Because the Dorado cannot display 1024 by 768 real-color images, the red, green, and blue components of the image must be separately exposed. DunnSnap will automatically photograph a 24 bit image. Or the image may be shot manually by following these steps:

1. Set the Dunn to separate mode (either via software or with the front panel switch).
2. Copy the red component of the image into the Dorado frame buffer.
3. Expose the film (either via software or with the front panel switch).
4. Copy the green component of the image into the Dorado frame buffer.
5. Expose the film.
6. Copy the blue component of the image into the Dorado frame buffer.
7. Expose the film. After this exposure, the film will automatically advance and
the camera is ready for a new image.

Previewing Images

To view the image being sent to the Dunn through the SLR camera:

1. Open the side panel to the Dunn.
2. Change the Video Preview from NORM to RED.
3. On the front panel, press FOCUS and EXPOSE (will automatically reset after 30 seconds).
4. Look only at Red, Green or Blue individually (switch using video preview); switching will
cause a glitch in the Dorado color monitor; this is okay.
5. When done previewing, set the Video Preview to Normal.
6. Close the panel door (to eliminate potential light leaks).
7. Switch from FOCUS to NORMAL.
8. Switch RESET until at beginning of Red-Green-Blue sequence.

Bugs

Techniques to establish, use, and maintain compensation tables (for grayscale and color) are needed.

The 16mm movie option for the Dunn is not discussed here. Ken Beckman is reputed to understand this option.

The conversion of resolution for the color monitor is awkward.

Notes

If a Dunn program is aborted, it may leave the Dunn in a reserved state, disallowing any further Dunn operations; the easiest solution is to reboot the Dicentra.

Unfortunately it is not yet known what warm-up period is needed for stable operation of the Dunn. It may be that the Dunn should always be left on.

Film is stored in the refrigerator of the video equipment room.

The ``exposure count'' of the Dunn refers to the number of frames, not exposures.

One should not adjust the internal controls unless strictly aware of the alignment procedures.

The Dunn box needs almost no maintenance. The only frequent operation is dusting the optics, which is done with a can of Dust-Off. Never touch the optics with a bodily surface; it will deposit oil on the glass. Never touch them with paper; the lenses are easily scratched.

Assistance with the hardware may be obtained through the Video Support Department (X4084), in particular, Mark Chow and Jim Cooper.