Abstract:
The invention concerns an optical imaging apparatus comprising (o) a light source (1) , (p) sample holding means, (q) an interferometer, (r) reference means, (s) an objective (8) which is adapted to have its sample side focal plane crossing a sample held in said sample holding means, (t) optical or electro-optical means (2, 3, 5, 16) adapted to produce a ring shaped or multi-spot light source in the front focal plane (17) or any conjugated plane (17') of said objective (8) , at least one detector. The invention also includes a method for using said apparatus where the sample is illuminated by an interference pattern and the depth information is obtained by using optical Coherence Tomography.
Abstract:
The present invention relates to an apparatus and a method combining achromatic complex FDOCT signal reconstruction with a common path and dual beam configuration. The complex signal reconstruction allows resolving the complex ambiguity of the Fourier transform and to enhance the achievable depth range by a factor of two. The dual beam configuration shares the property of high phase stability with common path FDOCT. This is of importance for a proper complex signal reconstruction and is in particular useful in combination with handheld probes such as in endoscopy and catheter applications. The advantages of the present invention are in particular the flexibility to choose arbitrarily positioned interfaces in the sample arm as reference together with the possibility to compensate for dispersion.
Abstract:
Es wird beschrieben eine Vorrichtung zur interferometrischen Messung einer Probe, insbesondere des Auges, mit einer Interferometeranordnung, welche einen ersten Meßstrahlengang, durch den ein Meßstrahl auf die Probe fällt, und einen ersten Referenzstrahlengang aufweist, durch den ein Referenzstrahl läuft, der mit dem Meßstrahl zur Interferenz gebracht wird, wobei die Interferometeranordnung einen zweiten Meß- und/oder zweiten Referenzstrahlengang aufweist, dessen/deren optischen Weglänge sich von der eines der ersten Strahlengänge unterscheidet, wobei die Weglängendifferenz gemäß einem Abstand zweier in Tiefenrichtung der Probe beabstandeter Meßbereiche gewählt ist.
Abstract:
The subject of invention is a method of fast imaging of objects by means of spectral optical coherence tomography using partially coherent light comprising a matrix of detectors with a memory, specially suitable for medical imaging. This is accomplished with a partially coherent light source 1, an interferometer equipped with a beam splitter 2 and reference mirror 3, a probing scanner 4, a matrix of sensors with a memory 8, a spectrograph comprising 7, and a data processor. It is distinguished from other methods of synchronization of probing scanner 4 movements with the recording of interference spectra, by recording the signals originating from the interference spectra of consecutive points of the object 6 in the matrix of photo-detectors 8. Simultaneously with the probing scanner 4 movement to the next point in the cross-section of the object 6, all previously registered spectra are transferred to the memory within the detector matrix 8. The information is subsequently transferred to an appropriate data processor and the cross-sectional image reconstructed by means of numerical Fourier transform.
Abstract:
The present invention relates to an apparatus and a method combining achromatic complex FDOCT signal reconstruction with a common path and dual beam configuration. The complex signal reconstruction allows resolving the complex ambiguity of the Fourier transform and to enhance the achievable depth range by a factor of two. The dual beam configuration shares the property of high phase stability with common path FDOCT. This is of importance for a proper complex signal reconstruction and is in particular useful in combination with handheld probes such as in endoscopy and catheter applications. The advantages of the present invention are in particular the flexibility to choose arbitrarily positioned interfaces in the sample arm as reference together with the possibility to compensate for dispersion.
Abstract:
The invention relates to a device for the interferometric measurement of a sample, in particular the eye, comprising an interferometer arrangement which comprises a first measurement beam path, through which a measurement beam falls onto the sample, and a first reference beam path, through which a reference beam runs, which is applied to the measuring beam for interference. The interferometer arrangement comprises a second measuring beam path and/or second reference beam path, whereby the optical wave lengths thereof are different from one of the first beam paths. The wave length difference is selected according to a distance of two measuring areas which are arranged at a distance in the depth direction of the sample.
Abstract:
Es wird eine Vorrichtung beschrieben zur interferometrischen Messung einer Probe (P), insbesondere des Auges (A), mit einer Interferometeranordnung (1), welche einen ersten Meßstrahlengang, durch den ein Meßstrahl auf die Probe fallt, und einen ersten Referenzstrahlengang (R) aufweist, durch den ein Referenzstrahl lauft, der mit dem Meßstrahl zur Interferenz gebracht wird, wobei die Interferometeranordnung einen zweiten Meß- und/oder zweiten Referenzstrahlengang (R2) aufweist, dessen/deren optischen Weglange sich von der eines der ersten Strahlengange unterscheidet, wobei die Weglangendifferenz gemäß einem Abstand zweier in Tiefenrichtung der Probe beabstandeter Meßbereiche (5, 6, 7) gewählt ist.
Abstract:
Optical Coherence Tomography (OCT) is an imaging technique with high axial resolution in the micro-meter-scale range combined with a high sensitivity allowing for example to probe weakly back-scattering structures beneath the surface of biological tissues up to several millimeters. A major improvement of this conventional technique represents Fourier Domain OCT with a further decrease in image acquisition time and additional sensitivity. The apparatus including appropriate signal processing reconstructs the depth profile from the spectrally resolved light signal generated by a broadband source and an interferometric imaging system. By frequency shifting the light fields with frequency shifting means in the reference and sample arm a phase resolved signal at high speed can be registered. Therefore the reference arm does not rely on arm length changes or delays. The beating signal generated in this way shows high phase stability. The phase of this beating signal is not wavelength dependent, as the frequency shift applied is the same for all wavelengths. Moreover this results in an additional suppression of unwanted auto-correlated distortion as well as an extended depth range.