Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Three Dimensional Measurements by Deflectometry and Double Hilbert
  Transform   An improved phase retrieval method based Hilbert transform is introduced to
quantitatively calculate the phase distribution from distorted fringe pattern.
Also phase measurement deflectomety are widely used in specular type samples.
The background noise or bias should be suppressed prior to apply Hilbert
transform. A method for suppression background noise double Hilbert transform
is presented, which requires only one image. The method is easy to implement,
and it is able to conducting automated fast measurements. We have demonstrated
the double Hilbert transform method to retrieve the phase and background
suppression by computer simulation and experiment in phase measuring
deflectometry method.

36
The categories of this paper are: cmp-lg
2
The categories of this paper are: math
7
The categories of this paper are: hep-th
0
The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
28
The categories of this paper are: alg-geom
37
The categories of this paper are: supr-con
12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph
19
The categories of this paper are: eess