scholarly journals Depth estimation of the absorbing structure in a slab turbid medium using point spread function

2020 ◽  
Vol 3 (SI3) ◽  
pp. First
Author(s):  
Ngoc An Dang Nguyen ◽  
To Ni Phan Van ◽  
Kohei Yamamoto ◽  
Minh Quang Nguyen ◽  
Anh Tu Tran ◽  
...  
Keyword(s):  
Blood Vessel ◽  
Point Spread Function ◽  
Near Infrared ◽  
Fluorescent Imaging ◽  
Turbid Medium ◽  
New Technique ◽  
Infrared Light ◽  
Near Infrared Light ◽  
Point Spread ◽  
Spread Function

Nowadays, transillumination imaging is more popular used in the medical field with the development of the vein finder and the non-invasive diagnosis applications. Near-infrared light with a wavelength of 700 - 1200 nm has relatively high transmission through biological tissue. Using near-infrared light, we can able to obtain a two dimensional (2D) transillumination image of the internal absorption structure such as blood vessel structure, liver ... in the body noninvasively. Even with a simple system (light-emitting diode (LED)'s array and low-cost camera), we could obtain the blood vessel transillumination image of human arm. However, the image is severely blurred due to the strong scattering in the tissue. We have devised the depth-dependent point spread function (PSF) to suppress the scattering effect in fluorescent imaging. In previous studies, we successfully applied this principle and developed a technique to reconstruct the absorbing structure in a turbid medium without using fluorescent material. The feasibility and effectiveness of the proposed technique were verified in experiments. However, this point spread function (PSF) is depth dependence, so that the depth information is required in practice. In order to make this method more practical, the new techniques for estimating the parameters of absorbing structure (depth and width) in the turbid medium by convolution and de-convolution with the point spread function (PSF) were devised. This paper presents a new technique for the estimation depth of an absorber in 2D transillumination image. This new technique was developed to estimate the depth of the absorber in turbid medium by convolution operation with the point spread function (PSF). By observing images with two-wavelength selected at which the scattering property of the medium is different. The transillumination image at one of the wavelengths is convolved with the PSF of another wavelength. Two images of alternative wavelengths are compared while changing the depth of the PSF. We can obtain the correct depth that gives a minimum difference between the two convoluted images. This technique does not require the repetition of the unstable deconvolution operation. The effectiveness of the proposed technique was verified in simulation and experiment.

scholarly journals Deep point spread function photometric catalog of the VVV survey data

2019 ◽  
Vol 632 ◽  
pp. A85
Author(s):  
M. Zhang ◽  
J. Kainulainen
Keyword(s):  
Point Spread Function ◽  
Near Infrared ◽  
Infrared Imaging ◽  
Galactic Plane ◽  
High Reliability ◽  
Point Spread ◽  
Deep Point ◽  
Spread Function ◽  
Local Crowding ◽  
Source Number

Context. The Vista Variables in the Vía Láctea (VVV) survey has performed a multi-epoch near-infrared imaging of the inner Galactic plane. High-fidelity photometric catalogs are needed to utilize the data. Aims. We aim at producing a deep, point spread function (PSF) photometric catalog for the VVV survey J-,H-, and Ks-band data. Specifically, we aim to take advantage of multiple epochs of the survey to reach high limiting magnitudes. Methods. We developed an automatic PSF-fitting pipeline based on the DaoPHOT algorithm and performed photometry on the stacked VVV images in J,  H, and Ks bands. Results. We present a PSF photometric catalog in the Vega system that contains about 926 million sources in the J,  H, and Ks filters. About 10% of the sources are flagged as possible spurious detections. The 5σ limiting magnitudes of the sources with high reliability are about 20.8, 19.5, and 18.7 mag in the J,  H, and Ks bands, respectively, depending on the local crowding condition. Our photometric catalog reaches on average about one magnitude deeper than the previously released PSF DoPHOT photometric catalog and includes less spurious detections. There are significant differences in the brightnesses of faint sources between our catalog and the previously released one. The likely origin of these differences is in the different photometric algorithms that are used; it is not straightforward to assess which catalog is more accurate in different situations. Our new catalog is beneficial especially for science goals that require high limiting magnitudes; our catalog reaches such high magnitudes in fields that have a relatively uniform source number density. Overall, the limiting magnitudes and completeness are different in fields with different crowding conditions.

Hardware and Software Complex for Detection and Visualization of Subsurface Blood Vessels During Brain Tumors Resection

2021 ◽  
Vol 91 (3) ◽  
pp. 55-66
Author(s):  
A. M. Udeneev
Keyword(s):  
Brain Tumor ◽  
Brain Tumors ◽  
Blood Vessel ◽  
Blood Vessels ◽  
Endoscopic Resection ◽  
Near Infrared ◽  
Bovine Brain ◽  
Infrared Light ◽  
Near Infrared Light ◽  
Different Depths

Purpose: The purpose of this work is to prove the possibility of subsurface blood vessels detection during endoscopic resection of brain tumors using the method of endoscopy in red and near infrared light. Material and methods: This work was accomplished with an experimental setup, simulating the geometry of endoscopic resection of brain tumor. The setup realizes the backlight of operational field with light from diagnostic window of electromagnetic spectrum (650 1000 nm) and takes photos of operational field. After that special algorithm increases the contrast of the photos and detect subsurface blood vessels. The pieces of bovine brain have served as brain samples. And thin-walled transparent plastic tube with an internal diameter 1 mm filled with bovine blood has served as a blood vessel. The tube was placed into brain samples on different depths. Results: During the experiments the series of photos of bovine brain with artificial blood vessels located on different depths was received. For every photo contrast was increased and blood vessel was recognized. Conclusion: The series of experiments has showed the possibility to detect the blood vessels with outer diameter 1 mm in the depth of 2 mm and 3 mm in brain tissues using the method of endoscopy in red and near infrared light. The depth of 3 mm is enough for preliminary detection of blood vessel during the endoscopic resection of brain tumor.

PERFORMANCE OF BLIND DECONVOLUTION IN OPTOACOUSTIC TOMOGRAPHY

2011 ◽  
Vol 04 (04) ◽  
pp. 385-393 ◽  
Author(s):  
THOMAS JETZFELLNER ◽  
VASILIS NTZIACHRISTOS
Keyword(s):  
Point Spread Function ◽  
Near Infrared ◽  
Blind Deconvolution ◽  
Photoacoustic Imaging ◽  
Reconstructed Image ◽  
Optoacoustic Tomography ◽  
Point Spread ◽  
Spread Function ◽  
Old Mice ◽  
Unknown Point

In this paper, we consider the use of blind deconvolution for optoacoustic (photoacoustic) imaging and investigate the performance of the method as means for increasing the resolution of the reconstructed image beyond the physical restrictions of the system. The method is demonstrated with optoacoustic measurement obtained from six-day-old mice, imaged in the near-infrared using a broadband hydrophone in a circular scanning configuration. We find that estimates of the unknown point spread function, achieved by blind deconvolution, improve the resolution and contrast in the images and show promise for enhancing optoacoustic images.

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