Device for optical coherence tomography
In certain embodiments, a device for optical coherence tomography (OCT) includes a signal detection device and a computer arrangement. The signal detection device is designed to detect an interference signal (G(ω)) for an object to be imaged in an optical frequency range (ω). The computer arrangement is designed to determine intermediate signals (G 1 (k), G 2 (k)) in a spatial frequency range (k) from the interference signal (G(ω)), whereby each of the intermediate signals (G 1 (k), G 2 (k)) is dispersion-compensated for a different depth (z 1 , z 2 ) of the object. A locally resolved image signal (FFT 1 , FFT 2 ) is determined for each of the intermediate signals (G 1 (k), G 2 (k)) by applying a Fourier transformation to the particular intermediate signal (G 1 (k), G 2 (k)). A tomography signal (G(z)) is determined from the image signals (FFT 1 , FFT 2 ).
1. A device for optical coherence tomography (OCT), comprising:
a signal detection device designed to detect an interference signal (G(ω)) for an object to be imaged in an optical frequency range (ω), and
a computer arrangement designed to calculate, for each depth of a plurality of different deaths (z 1 , z 2 ) of the object, association instructions (M 1 , M 2 ) that are adapted for the particular depth (z 1 , z 2 ) to the dispersion caused by the object and to store the instructions (M 1 , M 2 ) in a memory,
the computer arrangement is further designed to determine:
a plurality of intermediate signals (G 1 (k), G 2 (k)) in a spatial frequency range (k) from the interference signal (G(ω)), whereby each of the intermediate signals (G 1 (k), G 2 (k)) is dispersion-compensated for the different depths (z 1 , z 2 ) of the object, each of the intermediate signals (G 1 ( k ), G 2 ( k )) determined starting from the interference signal (G(ω)) using the corresponding association instructions (M 1 , M 2 ),
a locally resolved image signal (FFT 1 , FFT 2 ) for each of the intermediate signals (G 1 (k), G 2 (k)) by applying a Fourier transformation to the particular intermediate signal (G 1 (k), G 2 (k)), and
a tomography signal (G(z)) from the image signals (FFT 1 , FFT 2 ).
2. The device according to claim 1 :
whereby the computer arrangement is furthermore designed to calculate association instructions (M 1 , M 2 ) with a model of the object.
3. The device according to one of claims 1 and 2 ,
whereby the computer arrangement is furthermore designed to determine an intermediate signal ({hacek over (G)}(k)) for depth determination in a spatial frequency range (k) from the interference signal (G(ω)) using given association instructions (T) for depth determination,
to determine a locally resolved image signal ({hacek over (G)}(z)) by applying a Fourier transformation (FFT T ) to the intermediate signal ({hacek over (G)}(k)) for depth determination, and
to determine the different depths (z 1 -z 2 ) for the intermediate signals (G 1 (k), G 2 (k)) on the basis of a detection of extreme points (E 1 , E 2 ) of the image signal ({hacek over (G)}(z)) for depth determination that represent local changes of the refraction index in the object.
4. The device according to claim 3 ,
whereby the computer arrangement is furthermore designed to calculate the association instructions (M 1 , M 2 ) on the basis of the positions (z 1 , z 2 ) and/or of the mutual intervals (|z 2 -z 1 |) of the detected extreme points (E 1 , E 2 ) of the image signal ({hacek over (G)}(z)) for depth determination, taking into account one or more refraction indices that is/are characteristic for the object medium in areas up to the positions (z 1 , z 2 ) of the extreme points (E 1 , E 2 ).