Portable Easy-To-Use Motion Controlled Tesselator
The Tesselator automates simple pan and tilt needs for shooting film. A camera controller is part of the system, which can be used with any stepper driven camera or switch-operated still camera. The system uses step and direction outputs for pan, tilt, and camera, which allows the system to be configured for any mechanical setup. All parameters are saved on an easy-to-use PC card. The system is run from a hand held jogbox with an LCD screen and a simple keypad.

The system is battery powered, uses only 2 watts, and can be powered with 7 to 63 volts DC, or 120VAC.

Tesselator Grids
In the Tesselator system, a grid is set up using the pan and tilt axes on a camera head.
The system automatically moves the head to each position on that grid and shoots film.
The film can either be a wedge on a film camera, or a shot bracket on a still camera.

The grid is set up using the field of view of the camera to calculate grid size.  The following variables can be modified from their defaults:

The focal length of the lens being used.
Actual film horizontal and vertical aperture.
Desired overlap (as a % of field of view).
Landscape/portrait camera orientation.
Pan and tilt start positions (in degrees).
  • The start positions define either the center or one corner of the grid.
Number of tiles for pan and tilt.
  • If the tile number is negative, the direction for that axis is reversed.
  • This allows the ‘move’ to start from any corner of the grid.
These items determine the grid. See the menu descriptions for more.
There is a built-in ? second delay after the head moves to a grid position before film is shot, to allow the mechanical system to settle.

Shooting Film
There are 2 possibilities for shooting film at each position on the grid, a still camera or a stepper driven film camera.
Still camera (EOS mode):
Film is shot using 1 or 2 dry-contact relay outputs as switch closures. There are two outputs for each relay, so the outputs are isolated. When a frame is shot, two things happen. The first relay closes, and a user-defined delay is started. After the delay time, the second relay closes. The user can enter any time duration for both relay closures. The idea is that the first switch is used to set (power) up a digital camera, and the second switch takes the frame (or a bracket). The first switch then continues to hold for as long as necessary to load the image.
Stepper driven film camera (Vista mode):
A film wedge needs to be shot at each grid position. The user defines the ramp-up and ramp-down accelerations separately, along with the maximum FPS of the camera. These three parameters determine the number of frames in the wedge.
The system records the frame number at every change in FPS. This allows exposure selection using frame numbers when editing. The system stores this information (in ascii format) along with a move when the move is saved on a PC card.
There is a shoot switch input on the system to trigger moves or slates.
A built-in camera controller allows slates to be shot. The user enters the number of frames to shoot (positive or negative), and the desired FPS. The bloop light triggers at the top speed of the camera ramp for all slate shots. The ‘slate’ bloop frame is displayed on the LCD screen and is saved to the card with a move. If you shoot another slate, the new bloop frame is displayed and overwrites the old one. The bloop light is also triggered at the top of the camera ramp on every wedge, so the user can position the bloop light anywhere in a scene. The ‘wedge’ bloop frame information is also saved in the move.
There is a preview mode built in to the ‘go to grid’ page. This can also be used for ‘manual’ shooting of a move. Just advance the camera head grid by grid in any direction with one button press, inspect the frame, and jog the head if you like to remove any flares. Then just press a button or the shoot switch to shoot a frame.

Pan and Tilt
The pan and tilt axes can be jogged with the arrow buttons on the jogbox, or with any 2 encoder wheels. The encoder inputs can be configured for response, smoothing and deadband. The jog buttons can be configured for top speed and smoothing.
User units are stored for both axes, in terms of pulses per 45 degrees.
This allows the jogbox screen to display degrees for pan and tilt.
Negative user units reverse the motor direction.
Soft limits (in degrees) are configurable for both axes.
The user can send pan and tilt to any grid number or position required.
The system is set up also to easily go to the start of a grid move, or to zero position.
The user can easily set zero or any position for pan and tilt.
There are also 6 user-defined positions available. Just set a desired position in memory, then send the pan and tilt to that position, each operation requires just 2 button presses.

PC Card
Moves are saved on an SRAM PC card (PCMCIA card).  All data is saved in a move.
The user can load, save and delete moves on the card, and format a new card.
Cards are hot-swappable; you can insert and remove them while the system is on.
When the camera is stepper based, ASCII data is included for every wedge shot.  This includes the latest slate bloop frame, number of frames in the wedge, and the frame number for every change in FPS for the last wedge shot. There is a bloop frame at the top of every wedge, which is recorded also.
The ASCII data is readable by any computer with a PC card slot.
This data can also be read on the LCD screen.
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