|Knowledge about all aspects of 3D displays and their application.|
|We have used several setups for taking 3D photographs, our current hardware is described below, along with the basic steps for taking a photograph using the binocularity camera calculator spreadsheet (BCC).|
First chose which 3D display to target the photograph at, in this case it is the True3Di 26" HD display, which provides 1920x1200 resolution per eye. The display is 530mm wide and we choose a nominal viewing distance of 1400mm, and choose to use a display depth budget of +/-120mm.
Then compose the view of the scene and enter the camera and scene parameters, in this case a 50mm lens in portrait mode (and therfore a 24mm sensor width) and a total depth range in view of the camera of 200-240cm. The BCC will then work out the inter-axial setting for us (160mm).
The hardware rig using two Canon EOS 5D mkii cameras and wireless Pocket Wizards to synchonize them is illustrated below, the mechanics are standard items from Newport. Before taking a picture we setup and test the focus, aperture and white balance so that each camera is shooting with the same parameters, the cameras are switched to manual mode so that these settings don't change when we release the shutter for the stereo shot.
The images directly from the cameras need cropping to remove the horizontal offset and set the zero disparity plane correctly, the BCC calculates the cropping required, or more easily it can be removed using the StereoPhoto Maker (SPM) interactive cropping tools.
Even with the best cameras and careful mechanical alignment of the rig it is unlikely the stereo pair will be geometrically aligned. Therefore we normally run the SPM auto-alignment option to correct as much of the remaining geometric mis-alignments as possible. Unlike our earlier camera rigs the EOS 5D mkii seem to be well matched for colour and brightness and we have not needed to adjust these.
The resulting stereoscopic image of a simple test scene is shown below.
The equipment setup and image above by: Paul Gorley, Djamel Hassaine and Nick Holliman at the Durham Visualization Laboratory.
A full colour, high resolution (2Kx1K) stereoscopic version of the above can be downloaded from here DVL Stereoscopic Test Scene.
 PocketWizard multiMAX, in this setup we use three, one per camera in receive mode (with Canon trigger cables) and one in transmit mode to trigger them.
 Newport mounting mechanics:
1 x PRL-24 PRL Rail, 24 in. (609.6 mm)
2 x M-PRC-3 PRL Carrier, Metric
3 x CB-2-M Construction Bases, 63.5 x 88.9 mm, Metric
Plus assorted screws from these kits:
M-SK-SH-M6 Stainless Steel Screw Kit, M6 (for joining up the mechanics)
SK-25A Black Oxide Screw Kit, 1/4-20 (for the camera tripod mounting screw)
TA-M6Q20-10 M6 to 1/4-20 Adaptor screw (if you want to connect the camera directly to metric mechanics)
 Stereophoto Maker is free software (for windows only) and there is a link to it from the resources page.