Improving 3D cameras
Dr Adrian Dorrington from the School of Engineering at the University of Waikato is conducting research in the field of optoelectronics. His work is involved with finding out how 3D cameras can be improved to provide higher-quality images and more accurate information.
How we see 3D
Dr Adrian Dorrington, a scientist from the University of Waikato, explains how the brain interprets the images our two eyes receive. The net result is that we experience depth perception. 3D television works in a similar way. By wearing special glasses, two pictures are shown at the same time, one to each eye. The brain interprets this such that we see in 3D.
How we see 3D
The idea behind 3D is that we see stereoscopically. 3D TV or films work by showing two pictures at the same time, with each picture delivered to individual eyes – we see one picture with one eye and the other picture with the other eye – so it’s tricking the brain into seeing a three-dimensional image.
3D camera technology
Adrian’s research is looking at time-of-flight 3D cameras, which are different from stereoscopic 3D TV cameras. While three-dimensional cameras have been in use for a few years, the technology is still relatively new and needs to be refined.
Time-of-flight 3D cameras
University of Waikato scientist Dr Adrian Dorrington is investigating different applications of 3D cameras. The camera emits light, and the time of flight from camera to object and back again is measured. One application of this type of camera is in assessing the height of customers entering and leaving premises for security reasons.
A time-of-flight 3D camera records the amount of light arriving at each pixel in the image and also measures the distance between the object and the camera, providing information about depth and making it possible to create a 3D image of what has been photographed.
There is a problem that occurs often in current commercial 3D cameras – the multi-path problem – where the light takes a secondary route back to the camera, making the distance measured incorrect. For example, this can happen if the reflected light bounces off something else on its way, which can result in inaccurate readings. The 3D image produced in such a way contains incorrect distance measurements and is not very useful.
Improving accuracy of 3D cameras
Using time-of-flight 3D cameras for measurement applications has its operational problems. University of Waikato scientist Dr Adrian Dorrington explains what these are and how they can be remedied. For example, a solution to interference of light sent out by the camera has been solved by encoding the light. The reflected light received by the camera can be identified from this encoding.
The way Adrian tries to correct this problem is to take two measurements instead of one and to change the encoding method for each measurement. The information received still needs to be refined, which is achieved by applying mathematical formulae that address inaccuracies that are being measured and allow Adrian and his team to work out the real distance.
Adrian and his team run these mathematical simulations as well as practical experiments to help solve this problem, and their work is heavily maths based.
3D camera applications
Improving the accuracy of 3D cameras allows people to use them for interactive gaming and gesture control, as well as in medicine, for example, by using 3D images for more accurate and less invasive detection of tumours.
Applications of time of flight cameras
Time-of-flight technology can be adapted to suit a variety of applications. Dr Adrian Dorrington from the School of Engineering at the University of Waikato explains some of the medical applications as well as user-interface control. For example, the shape of a person can be measured using time-of-flight cameras, and this could be of assistance in reconstructive surgery.
3D imaging can also be used for security purposes, and Adrian and his team’s advances should help to make these more successful.
