scholarly journals In situ measurement of the isoplanatic patch for imaging through intact bone

2020 ◽  
Author(s):  
Kayvan Forouhesh Tehrani ◽  
Nektarios Koukourakis ◽  
Jürgen Czarske ◽  
Luke J Mortensen
Keyword(s):  
Phase Conjugation ◽  
Field Of View ◽  
Optical Phase Conjugation ◽  
Optical Aberrations ◽  
Intact Bone ◽  
Old Adult ◽  
Wavefront Shaping ◽  
Age Range ◽  
Phase Accumulation

AbstractWavefront-shaping (WS) enables imaging through scattering tissues like bone, which is important for neuroscience and bone-regeneration research. WS corrects for the optical aberrations at a given depth and field-of-view (FOV) within the sample; the extent of the validity of which is limited to a region known as the isoplanatic patch (IP). Knowing this parameter helps to estimate the number of corrections needed for WS imaging over a given FOV. In this paper, we first present direct transmissive measurement of murine skull IP using digital optical phase conjugation (DOPC) based focusing. Second, we extend our previously reported Phase Accumulation Ray Tracing (PART) method to provide in-situ in-silico estimation of IP, called correlative PART (cPART). Our results show an IP range of 1-3 μm for mice within an age range of 8-14 days old and 1.00±0.25 μm in a 12-week old adult skull. Consistency between the two measurement approaches indicates that cPART can be used to approximate the IP before a WS experiment, which can be used to calculate the number of corrections required within a given field of view.Abstract Figure

scholarly journals Optical Phase Conjugation Using Nonlinear SOA for Nonlinearity and Dispersion Compensation of Coherent Multi-Carrier Lightwave Systems

IEEE Access ◽  
2021 ◽  
Vol 9 ◽  
pp. 44059-44068
Author(s):  
Lakshmi Narayanan Venkatasubramani ◽  
Aneesh Sobhanan ◽  
Anirudh Vijay ◽  
R. David Koilpillai ◽  
Deepa Venkitesh
Keyword(s):  
Phase Conjugation ◽  
Dispersion Compensation ◽  
Optical Phase Conjugation ◽  
Optical Phase

scholarly journals Enhancing the Signal Power Symmetry for Optical Phase Conjugation Using Erbium-Doped-Fibre-Assisted Raman Amplification

IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 222766-222773
Author(s):  
Mingming Tan ◽  
Tu Thanh Nguyen ◽  
Pawel Rosa ◽  
Mohammad Ahmad Zaki Al-Khateeb ◽  
Tingting Zhang ◽  
...  
Keyword(s):  
Phase Conjugation ◽  
Signal Power ◽  
Optical Phase Conjugation ◽  
Raman Amplification ◽  
Optical Phase ◽  
Erbium Doped

scholarly journals Extrinsic Camera Calibration with Line-Laser Projection

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1091
Author(s):  
Izaak Van Crombrugge ◽  
Rudi Penne ◽  
Steve Vanlanduit
Keyword(s):  
Camera Calibration ◽  
Real World ◽  
Large Scale ◽  
State Of The Art ◽  
Bundle Adjustment ◽  
Field Of View ◽  
Extrinsic Calibration ◽  
Practical Procedure ◽  
Partial Overlap

Knowledge of precise camera poses is vital for multi-camera setups. Camera intrinsics can be obtained for each camera separately in lab conditions. For fixed multi-camera setups, the extrinsic calibration can only be done in situ. Usually, some markers are used, like checkerboards, requiring some level of overlap between cameras. In this work, we propose a method for cases with little or no overlap. Laser lines are projected on a plane (e.g., floor or wall) using a laser line projector. The pose of the plane and cameras is then optimized using bundle adjustment to match the lines seen by the cameras. To find the extrinsic calibration, only a partial overlap between the laser lines and the field of view of the cameras is needed. Real-world experiments were conducted both with and without overlapping fields of view, resulting in rotation errors below 0.5°. We show that the accuracy is comparable to other state-of-the-art methods while offering a more practical procedure. The method can also be used in large-scale applications and can be fully automated.

Optical phase conjugation in novel azo-dye-doped PMMA films

1996 ◽  
Author(s):  
Andre Granger ◽  
Vinh P. Pham ◽  
Tigran V. Galstian ◽  
Roger A. Lessard
Keyword(s):  
Azo Dye ◽  
Phase Conjugation ◽  
Optical Phase Conjugation ◽  
Optical Phase
Sign in / Sign up

Export Citation Format

Share Document