Results 331 to 340 of about 3,110,122 (363)

Contrast sensitivity of the visual system in speckle imagery

Journal of the Optical Society of America A, 1994
The contrast sensitivity function (CSF) of the whole visual system is determined with the use of coherent diffuse illumination. This function provides supplementary data about the effect of speckle on the ability of the visual system to perceive the spatial information contained in an image. The results show that speckle not only prevents perception of
M. J. Buades, A. Felipe, J.M. Artigas
openaire   +3 more sources

Efficient Processing of Laser Speckle Contrast Images

IEEE Transactions on Medical Imaging, 2008
Though laser speckle contrast imaging enables the measurement of scattering particle dynamics with high temporal resolution, the subsequent processing has previously been much slower. In prior studies, generating a laser speckle contrast image required about 1 s to process a raw image potentially collected in 10 ms or less.
Adrien Ponticorvo, Andrew K. Dunn, W. J. Tom   +2 more
openaire   +2 more sources

Clinical efficacy of bowel perfusion assessment during laparoscopic colorectal resection using laser speckle contrast imaging: A matched case–control study

Asian Journal of Endoscopic Surgery, 2019
Disadvantages of bowel perfusion assessment with indocyanine green fluorescence angiography include the need for a fluorophore and the subjective nature of the assessment.
Shigehiro Kojima, T. Sakamoto, Yutaka Matsui, K. Nambu, K. Masamune   +4 more
semanticscholar   +1 more source

Perceptual assessment of laser‐speckle contrast

Journal of the Society for Information Display, 2012
Abstract— A procedure is described for perceptually assessing the effects of laser speckle on target discrimination in the context of developing a laser‐display measurement standard. The perceptual approach avoids the difficulties inherent in assessing speckle contrast photometrically.
Logan Williams, George A. Geri
openaire   +2 more sources

Laser speckle contrast imaging in neurosurgery: a systematic review.

World Neurosurgery, 2022
A. Konovalov, V. Gadzhiagaev, F. Grebenev, D. Stavtsev, G. Piavchenko, Alexander Gerasimenko, Dmitry V. Telyshev, Igor V. Meglinski, S. Eliava   +8 more
semanticscholar   +1 more source

Fingerprint Presentation Attack Detection using Laser Speckle Contrast Imaging

Biometrics and Electronic Signatures, 2018
With the increased deployment of biometric authentication systems, some security concerns have also arisen. In particular, presentation attacks directed to the capture device pose a severe threat.
Pascal Keilbach, Jascha Kolberg, M. Gomez-Barrero, C. Busch, Hanno Langweg   +4 more
semanticscholar   +1 more source

Laser speckle contrast imaging of blood flow in the deep brain using microendoscopy.

Optics Letters, 2018
Poor blood flow circulation can occur in the subcortical regions of the brain in many brain diseases. However, the limitations of light penetration imaging techniques hinder the detection of blood flow in deep brain tissues in vivo. Hence, in this Letter,
Ming Chen, Dong Wen, Songlin Huang, Shen Gui, Zhihong Zhang, Jinling Lu, Pengcheng Li   +6 more
semanticscholar   +1 more source

Contrast Variation of Non-gaussian Speckle

Optica Acta: International Journal of Optics, 1980
Intensity fluctuations of laser light scattered from a random phase medium into a far-field on-axis observation point are analysed theoretically assuming a gaussian phase variation of the medium and a gaussian laser beam profile. The results give a theoretical background of the past experiments concerning the contrast variation of non-gaussian speckle ...
openaire   +2 more sources

Detrimental effects of speckle-pixel size matching in laser speckle contrast imaging

Optics Letters, 2008
Through a series of simulations and experiments, we demonstrate that the frequently cited criterion of matching speckle size to detector element (pixel) size in laser speckle contrast imaging (LSCI) has the detrimental effect of reducing the contrast and thereby decreasing the variation in the laser speckle contrast image.
Elaine M. Wells-Gray, Sean J. Kirkpatrick, Donald D. Duncan   +2 more
openaire   +3 more sources

Assessment of the test‐retest reliability of human gingival blood flow measurements by Laser Speckle Contrast Imaging in a healthy cohort

Microcirculation, 2018
The reliability of gingival blood flow measured by Laser Speckle Contrast Imaging is unknown. Our aim was to investigate the effect of factors inherent in oral mucosa measurement on intra‐day and inter‐day reliability.
E. Molnár, R. Fazekas, Zsolt M. Lohinai, Z. Tóth, J. Vág   +4 more
semanticscholar   +1 more source