UofK ALPHA SCANNER DESIGN

Updated 2-9-2010

You can make a simple scanner out of wood. The idea is to fix the projector in place but have the camera rotate such that their optical axes can be aligned. Once aligned, the camera is locked in place. Then the sensor is calibrated. The rectangle unit that the camera and projector are on, can be rotated in elevation (tilt) so that the device can be aimed at different targets without recalibration. Azimuth (pan) angle is obtained by rotating the entire unit. You will need a drill, probably ¼-20 bolts and be a bit handy to build the simple scanner device. We have built these from 8020 aluminum extrusions. The system is easily scaled. The distance between the camera and projector is typically (1) 9 to 12 inches for a face scan, (2) 24 inches for an upper body scan and (3) 48 inches for a full body scan.

A uEye camera and 3M projector system is shown above. These were early scans so the problems may go away as we optimize the UofKscanner settings. The left scan of Alice shows a residual of the cross hair. May just require more delay before capturing the image (this is a setting in Projector Controls) and the right picture is a metallic surface on Alice showing something we have not seen before: Banding along the vertical (along the phase dimension)? This would either be aliasing with the low resolution 3M projector or something we do not understand? From what we can tell the uEye seems to be a good camera but we really need to evaluate this weird banding and verify giving it more time to capture. It also has sync capability which would probably make a profound improvement in speed. We have seen this with Matrix Vision BlueFoxes and video synching is extremely important if you want speed.

To demonstrate making your own scanner, the above scanner was made from a Logitech QuickCam Pro 4000 and a 3M MPro 110. This scanner is inexpensive and you can run on battery power only at remote sites albeit NOT ruggedized. I have made the simple scanner structure before but the truth is I have a lot of different parts to grab from and a lot of shop equipment to work with. So I removed the Pro 4000 from its little ball cover and mounted it in a lexan plastic plate. That is then mounted onto an articulating arm purchased from Edmunds scientific. At the base of the arm, a metal flange plate you can get at most hardware stores is used to mount the 3M projector. I glued some cork material (neoprene washer would work too) to the flange so the projector would not rotate and used a ¼-20 machine screw to clamp it down. The articulating base was pirated from an old Ethernet security camera and then mounted on a circular wood base. I used cable ties to strap down all the wires. One piece of advice is you should always use at least two ties to strap down your wires, else when the wire is moved, the torque is transmitted to the connector which will eventually fail, disconnect or misalign the camera or projector. You should also leave enough wire by the connector so you can unplug the connectors whenever you ship or transport the device, else if the connector is bumped hard enough during transport, it will break the device side of the connector. Below are some other photos of the device.