My research is around 3D imaging, but my knowledge limited by techniques such as holography which I met in the daily life. And as a result, often I didn't notice the technical innovations in optics, which can be very practical and useful.
So, which optoelectronics elements developed in the last time you meted and how they can be applied in the 3D imaging?
The intention is not only to general methods, for example such as Integral Imaging, but more in the direction of the specific non ordinary details such as lenslet array. Details which we do not use in our everyday live.
Relevant references are welcomed.
Thank you in advance.
Little bit. I want to expand knowledge on the subject, to understand if it may or may not be relevant to my research.
Hi Vladimir,
I think the answer really depends on the scale of the objects you plan to measure. If you want to measure buildings, artwork, etc., then probably time-of-flight detectors can be sufficient. For example check this interesting TED talk:
http://www.ted.com/talks/ben_kacyra_ancient_wonders_captured_in_3d
However, if you want to create a 3D model of small scaled objects, then several other methods are commonly used:
1. Triangulation - in which the distance from a sensor to a given surface is measured by using a light source and a detector that are mounted with a known relative angle between them. Then, after identifying the energy distribution location of the reflected light on the sensor's detector, it is possible to calculate the distance using trigonometric identities. Note that shadowing effects prevent this technique from measuring steep angles and inside holes.
2. Structured light 3D scanning - in which a light pattern (usually fringes) is projected on the specimen, a camera records the bending of the light pattern, and computer algorithms compute the structure of the object:
http://en.wikipedia.org/wiki/Structured-light_3D_scanner
This technique allows fast data acquisition at the cost of measurement accuracy since the entire object can be measured at once (i.e., without the need for scanning motors).
3. Conoscopic holography - in which polarized light that hits a measured surface reflects back into the sensor and then guided through anisotropic optical crystal. In this way a fringe pattern is formed that can be calibrated to give the distance between the object and the sensor. Since the light leaves the detector and returns into it on the same path, these sensors are known as collinear and can measure inside holes and cover wide angles. Optimet sells and manufactures these sensors:
http://www.optimet.com/our_technology.php
I hope it helps,
Assaf
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