Search Results for speckle

FIG. 4.3 Illustrating bright and dark speckle in one dimension. (a) An array of scatterers and (b) the corresponding OCT signal exhibiting regions of bright and dark speckle. More about this image found in Illustrating bright and dark speckle in one dimension. (a) An array of scat...

FIG. 4.10 (a) Speckle contrast as a function of the number of averaged independent speckle realizations, N, for amplitude and intensity. (b) Speckle SNR as a function of N for amplitude and intensity. More about this image found in (a) Speckle contrast as a function of the number of averaged independent sp...

FIG. 4.13 (a) Speckle contrast and (b) SNR in a region containing both a specular reflection and diffuse scatterers (resulting in a constant phasor plus random phasor sum) as a function of r. More about this image found in (a) Speckle contrast and (b) SNR in a region containing both a specular ref...

FIG. 4.14 Illustration of the relationship between speckle size and OCT resolution. (a) Simulated intensity for a single scatterer (representing the 2D PSF). (b) Simulated speckle pattern produced by a distribution of scatterers. (c) Plots comparing the PSF (blue) along the x-axis More about this image found in Illustration of the relationship between speckle size and OCT resolution. (...

FIG. 4.15 Demonstration of the relationship between speckle size and OCT resolution. Both images are of the same mouse aorta; however, (a) was taken on a system with an axial and lateral resolution (in air) of 7.8 µm and 11 µm, respectively, while (b) was taken on a system with a higher axial More about this image found in Demonstration of the relationship between speckle size and OCT resolution. ...

FIG. 4.16 Reducing speckle contrast using frequency compounding. OCT intensity B-scans of the same scattering phantom acquired with (a) a light source with a central wavelength of 1312 nm and a FWHM bandwidth of 36 nm and (b) a central wavelength of 1488 nm and a FWHM bandwidth of 57 nm More about this image found in Reducing speckle contrast using frequency compounding. OCT intensity B-scan...

FIG. 4.17 (a) OCT and (b) speckle-modulating (SM) OCT B-scans of a mouse cornea. (c) and (d) are magnified views of the regions indicated by yellow boxes in (a) and (b), respectively. (e) Microscope image of hematoxylin and eosin (H&E) stained mouse cornea at ten times magnification. Scale More about this image found in (a) OCT and (b) speckle-modulating (SM) OCT B-scans of a mouse cornea. (c) ...

FIG. 5.5 The impact of speckle on the accuracy of phase-sensitive OCT. Reference and translated scatterer locations, and corresponding OCT intensity, of (a) a single scatterer (specular reflector), (b) five scatterers constructively interfering (bright speckle), and (c) five scatterers More about this image found in The impact of speckle on the accuracy of phase-sensitive OCT. Reference and...

FIG. 5.9 Illustration of speckle tracking. Reprinted with permission from Zaitsev, V. Y. et al., J. Biomed. Opt. 19 (2), 021107 (2014a). Copyright 2014 SPIE. More about this image found in Illustration of speckle tracking. Reprinted with permission from Zaitsev...

FIG. 5.14 Changes of a speckle pattern in a homogeneous silicone phantom under an increasing compressive load applied to the top of the sample from (a) to (d). Note that the shape of the black outline changes as the load increases, highlighting changes in the speckle pattern. Image dimensions More about this image found in Changes of a speckle pattern in a homogeneous silicone phantom under an inc...

FIG. 4.9 Simulated OCT amplitude B-scans generated by averaging (a) 1, (b) 10, and (c) 100, independent speckle realizations. (d), (e), and (f) are speckle intensity B-scans from the speckle amplitudes in (a), (b), and (c), respectively. The speckle contrast in the OCT amplitude B-scans More about this image found in Simulated OCT amplitude B-scans generated by averaging (a) 1, (b) 10, and (...

FIG. 4.6 Scatterer distributions with different densities in (a), (b), and (c). Illustration of (d) no speckle, (e) partially developed speckle, and (f) fully developed speckle in the OCT amplitude corresponding to the scatterer distributions in (a), (b), and (c), respectively. Scale bars More about this image found in Scatterer distributions with different densities in (a), (b), and (c). Illu...

FIG. 4.8 B-scans of (a) amplitude, (b) intensity, and (c) phase for fully developed speckle. Analytical PDFs of (d) amplitude, (e) intensity, and (f) phase in fully developed speckle. Scale bars represent 20 µm. More about this image found in B-scans of (a) amplitude, (b) intensity, and (c) phase for fully developed ...

FIG. 4.1 OCT image of a human fingertip plotted on a logarithmic scale. A sweat duct obscured by speckle is highlighted in the inset. Examples of bright and dark speckle are indicated by the blue and red arrows, respectively. Scale bars represent 100 µm. More about this image found in OCT image of a human fingertip plotted on a logarithmic scale. A sweat duct...

FIG. 4.19 OCT, SNR, axial displacement, and axial strain A-scans of a mechanically homogeneous sample using compression OCE; (a)–(c) are generated without speckle reduction, and (d)–(f) are generated with speckle reduction brought about by spatial averaging. Adapted from Hepburn, M. S. et More about this image found in OCT, SNR, axial displacement, and axial strain A-scans of a mechanically ho...