This video explains the difference between the three modalities of OCT : time-domain, Spectrum-domain and Swept source OCT. A simple explanation of FFT is included
Very informative, very nice way of explaining. One thing to also note here is that the intensity of the light is also affected by the absorption of the tissue, which means that sometimes the constructive interference does not lead to the maximum amplitude even though the object is focused. In other words, noise can be generated by light traveres different types of tissues with different absorption factors. This effect makes the images sometimes blurry and noisy. Allow me to add something here, Fast-fourier Transformation OCT is only achieved using specialized line-cameras.
This was just what I was looking for, linking the theory with the practice. Thank you Sir! I wonder what is the reason that the swept single frequency light ray method (narrow-band) can get to and hence measure the deeper layers, when compared to the broad band light source method? Is it a matter of increased light power density assuming distances are kept the same? Looking forward to watch your other two videos. Thank you.
Thanks for the wonderful tutorial, it's vary helpful! I wander is it convenient for you share the lecture slides or notes, hope to make a note for future reference!
@@adelabdelshafik For spectal OCT, an inverse FFT is necessary to transform light spectrum (from the line camera) into time/spacial domain relevant to the pachymetry of eye.
@@AH-oo1oq I believe an engineer is needed to discuss such statement, which is beyond my ability as an ophthalmologist. If you find it useful for ophthalmologists following this channel, you may further explain that point.
@@adelabdelshafik Hi, sir, Can you talk something more about enhanced depth imaging, and difference between EDI- Cirrus HD OCT 5000 and EDI Heidelberg Spectralis. I don't understand how EDI technique works "Spectral domain can show to a little extend these deep structures when using a technique known as enhanced depth imaging, by pushing the instrument closer to the eye " . Thank you so much.
Hello Sir, I have a doubt. As you mentioned, in TDOCT the light source is monochromatic, but in the literature, it is mentioned that the light source is broadband with continuous waveform. If we use a monochromatic light source then the interference pattern still observes at the unequal path length difference. Thanks in advance
Hi thanks for the video, some basic ideas are still unclear to me: is the mirror movable in time domain OCT so we do not get destructive interference? How do we know when to move the mirror? Is this a closed loop system where the detector tells the mirror to move back when destructive interference is detected? thanks!
Hi. To start with I am not an engineer, , I guess the mirror is moving all the time for a fixed distance , as rays are reflected from different layers of retina simultaneously the detector will capture subsequent layers with constructive interface, this will result in detecting 5-6 layers of the retina with certain distance in between with no layer detected hence we can get a section in the retina. Finally have a look at this video : ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-j-u3IEgcTiQ.html
