SAMBA PRINCIPLE
 
 

 

Polarization-difference imaging is explained below, in the case of active imaging. The observed scene is illuminated by a controlled source with a known polarization state. In the example below, it is a verticall linear polarization state. The incident light is scattered by the object. The light collected by SAMBA carries both polarization states P and C. SAMBA camera successively acquires the crossed (C) and parallel (P) polarization state for each pixel of the image, at video rate.

SAMBA measures the depolarization of the polarized illumination for each pixel of the image. The acquisition of the 2 polarization images, P and C allows the calculation of various parameters for each pixels of the image:

Image
Formula
Specular (S)
S = P - C
Diffuse (D)
D = 2C
Intensity (I)
I = S + D = P + C
Degree of Polarization (DOP)
DOP = S/I = P-C/(P+C)
   
These polarization images contain numerous information about the observed scene. S is the specular image i.e. the image generated only by the light coming from the object surface. D is the diffuse image i.e. the image generated only by the light coming form the sub-surface/volume of the object. DOP is related to the gloss of the object (ratio specular/intensity).
For examples of images, applications and litterature about polarization difference imaging, please visit SAMBA resources page.
SAMBA can also be used in passive imaging, where the illumination is not controlled. SAMBA will detect the polarization of an un-polarized illumination (specular reflection for example). For more information about that application, please contact us.
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