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7.
Measurement principle
7.1.
Step 1: Acquisition of images
Once launched, the first step of a
measurement is the acquisition of
many couples of parallel and
crossed images. The set of parallel
and crossed images are averaged
to obtain one couple of parallel (1)
and crossed images (2).
By subtracting the averaged
crossed image (2) to the averaged
parallel image (1), we obtain the
averaged specular image (3).
The
diffused
image
(4)
corresponds to twice the crossed
image (2).
The sum of the parallel image and
the crossed images corresponds to
the intensity image (5), which is
the image a classical camera would
give.
All the images are acquired with a
12-bit depth resolution. The size of
the images is 582 (width) by 782
(length) pixels. To each pixel
corresponds an intensity value
between 0 (black) and 4095
(white). The exposure time is the
same during the acquisition of the
parallel and crossed images.
