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SD-OCT Base Unit Chapter 3: Description
Page 20 MTN012389-D02
Based on the intensity and phase differences in the interference patterns detected by both sensors, net
polarization changes as a function of depth in the sample are determined with the typical spatial resolution of
an SD-OCT system. As a parameter to display the cumulative polarization effect, the phase retardation, optical
axis and degree-of-polarization uniformity (short: DOPU) are available. Details are provided in the OCT Software
Manual (chapter 3.10. Polarization Sensitive Mode).
Nomenclature in OCT imaging
Figure 19 A-Scan Data Set
As described before, the SD-OCT engine creates a depth profile from the interference of photons reflected off
layers of the sample with photons reflected in the reference arm. This depth profile is referred to as A-scan.
Figure 19 shows a tomato’s A-scan data. The ordinate of this graph represents the modulation amplitude based
on the number of measured electrons per camera pixel. Other scales do not change the measurement.
The imaging application can make use of up to two scanning directions. When scanning one direction while
collecting multiple A-scans, a 2-dimensional cross-sectional image is created. This is referred to as a B-scan.
Here, the depth information is typically displayed from top to bottom, while the scan axis is from left to right.
Figure 20 shows a B-scan data set.
Figure 20 B-Scan Data Set