61 research outputs found
Colour Sensor White Balance Influence on White-Light Interferometer Resolution
Impact of a sensor color balance on white-light fullfieldoptical coherence tomography (FF-OCT)resolution is investigated in the paper. Full width athalf magnitude (FWHM) of a coherence pulse wascalculated for various white balance (WB) settings.Simulated dependence of FWHM on WB of asensor and experimental data are shown in thepaper. The minimum interference pulse width canbe achieved by the proper color balance coefficientschoice. And in this case the pulse is narrower thaneither one registered by colour image sensor withWB based on light source emission spectrum or bymonochrome image sensor
Dynamic time domain near-infrared optical tomography based on a SPAD camera
In many clinical applications it is relevant to observe dynamic changes in oxygenation. Therefore the ability of dynamic imaging with time domain (TD) near-infrared optical tomography (NIROT) will be important. But fast imaging is a challenge. The data acquisition of our handheld TD NIROT system based on single photon avalanche diode (SPAD) camera and 11 light sources was consequently accelerated. We tested the system on a diffusive medium simulating tissue with a moving object embedded. With 3D image reconstruction, the moving object was correctly located using only 0.2 s exposure time per source
Π’ΠΠΠ ΠΠ― ΠΠΠΠΠΠ‘-ΠΠ ΠΠ¦ΠΠ‘Π‘ΠΠ: Π€ΠΠ ΠΠΠΠ¬ΠΠ«Π ΠΠΠΠΠΠ Π ΠΠΠ’ΠΠΠ«
The basic directions of the modern theory of business processes. For each of these areas provides a brief overview of its main models and methods.Π Π°ΡΡΠΌΠ°ΡΡΠΈΠ²Π°ΡΡΡΡ ΠΎΡΠ½ΠΎΠ²Π½ΡΠ΅ Π½Π°ΠΏΡΠ°Π²Π»Π΅Π½ΠΈΡ ΡΠΎΠ²ΡΠ΅ΠΌΠ΅Π½Π½ΠΎΠΉ ΡΠ΅ΠΎΡΠΈΠΈ Π±ΠΈΠ·Π½Π΅Ρ-ΠΏΡΠΎΡΠ΅ΡΡΠΎΠ². ΠΠΎ ΠΊΠ°ΠΆΠ΄ΠΎΠΌΡ ΠΈΠ· Π½Π°ΠΏΡΠ°Π²Π»Π΅Π½ΠΈΠΉ ΠΏΡΠΈΠ²ΠΎΠ΄ΠΈΡΡΡ ΠΊΡΠ°ΡΠΊΠΈΠΉ ΠΎΠ±Π·ΠΎΡ Π΅Π³ΠΎ ΠΎΡΠ½ΠΎΠ²Π½ΡΡ
ΠΌΠΎΠ΄Π΅Π»Π΅ΠΉ ΠΈ ΠΌΠ΅ΡΠΎΠ΄ΠΎΠ²
Π€ΠΠ ΠΠΠΠ¬ΠΠ«Π ΠΠΠ’ΠΠΠ« ΠΠΠΠΠΠ ΠΠΠ Π ΠΠΠ ΠΠΠΠΠΠΠ¦ΠΠ ΠΠΠΠΠΠ‘-ΠΠ ΠΠ¦ΠΠ‘Π‘ΠΠ
The article describes a set of methods that allow keeping a formal investigation of business processes of enterprises and carrying out their functional-structural design, testing and verification.Π ΡΡΠ°ΡΡΠ΅ ΡΠ°ΡΡΠΌΠ°ΡΡΠΈΠ²Π°Π΅ΡΡΡ ΠΊΠΎΠΌΠΏΠ»Π΅ΠΊΡ ΠΌΠ΅ΡΠΎΠ΄ΠΎΠ², ΠΏΠΎΠ·Π²ΠΎΠ»ΡΡΡΠΈΡ
ΠΏΡΠΎΠ²ΠΎΠ΄ΠΈΡΡ ΡΠΎΡΠΌΠ°Π»ΠΈΠ·ΠΎΠ²Π°Π½Π½ΠΎΠ΅ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠ΅ Π±ΠΈΠ·Π½Π΅Ρ-ΠΏΡΠΎΡΠ΅ΡΡΠΎΠ² ΠΏΡΠ΅Π΄ΠΏΡΠΈΡΡΠΈΠΉ, ΠΎΡΡΡΠ΅ΡΡΠ²Π»ΡΡΡ ΠΈΡ
ΡΡΠ½ΠΊΡΠΈΠΎΠ½Π°Π»ΡΠ½ΠΎ-ΡΡΡΡΠΊΡΡΡΠ½ΠΎΠ΅ ΠΏΡΠΎΠ΅ΠΊΡΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅, ΡΠ΅ΡΡΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅ ΠΈ Π²Π΅ΡΠΈΡΠΈΠΊΠ°ΡΠΈΡ
Resolution and penetration depth of reflection-mode time-domain near infrared optical tomography using a ToF SPAD camera
In a turbid medium such as biological tissue, near-infrared optical tomography (NIROT) can image the oxygenation, a highly relevant clinical parameter. To be an efficient diagnostic tool, NIROT has to have high spatial resolution and depth sensitivity, fast acquisition time, and be easy to use. Since many tissues cannot be penetrated by near-infrared light, such tissue needs to be measured in reflection mode, i.e., where light emission and detection components are placed on the same side. Thanks to the recent advance in single-photon avalanche diode (SPAD) array technology, we have developed a compact reflection-mode time-domain (TD) NIROT system with a large number of channels, which is expected to substantially increase the resolution and depth sensitivity of the oxygenation images. The aim was to test this experimentally for our SPAD camera-empowered TD NIROT system. Experiments with one and two inclusions, i.e., optically dense spheres of 5mm radius, immersed in turbid liquid were conducted. The inclusions were placed at depths from 10mm to 30mm and moved across the field-of-view. In the two-inclusion experiment, two identical spheres were placed at a lateral distance of 8mm. We also compared short exposure times of 1s, suitable for dynamic processes, with a long exposure of 100s. Additionally, we imaged complex geometries inside the turbid medium, which represented structural elements of a biological object. The quality of the reconstructed images was quantified by the root mean squared error (RMSE), peak signal-to-noise ratio (PSNR), and dice similarity. The two small spheres were successfully resolved up to a depth of 30mm. We demonstrated robust image reconstruction even at 1s exposure. Furthermore, the complex geometries were also successfully reconstructed. The results demonstrated a groundbreaking level of enhanced performance of the NIROT system based on a SPAD camera
Development and validation of a sensor prototype for near-infrared imaging of the newborn brain
Imaging brain oxygenation is crucial for preventing brain lesions in preterm infants. Our aim is to build and validate a near-infrared optical tomography (NIROT) sensor for the head of neonates. This sensor, combined with an optoacoustic device, will enable quantitative monitoring of the structural and functional information of the brain. Since the head of preterm infants is small and fragile great care must be taken to produce a comfortable and compact device in which a sufficient number of light sources and detectors can be implemented. Here we demonstrate our first prototype. Heterogeneous silicone phantoms were produced to validate the prototype's data acquisition, data processing, and image reconstruction. Reconstructed optical properties agree well with the target values. The mechanical performance of the new NIROT sensor prototype confirms its suitability for the clinical application
Durability increase of mining dump trucks through the use of protective coatings of the body
The share of trucking in the total cost of open-cast mining is 50% or more. Therefore, reducing transportation costs is one of the tasks of increasing the technical and economic indicators of an open development method, which is an urgent task. Performance dump truck is estimated either by the volume of transported rock mass (in cubic meter or tons), or the value of cargo turnover (ton-kilometers). However, these indicators do not take into account the percentage of adhering rock that is transported uselessly and reduces productivity. The paper proposes methods for protecting the body of a mining dump truck from clay rocks adhering. Detail the method of protection with the help of vibration using metal structure is considered. A mathematical model of the stress-strain state of a two-layer beam is proposed. The dependence of the stress in the body on the stiffness of the elastic supports and impact energy when using a rubber lining is shown. Β© 2020 IOP Publishing Ltd. All rights reserved
Challenges and prospects for multi-chip microlens imprints on front-side illuminated SPAD imagers
The overall sensitivity of frontside-illuminated, silicon single-photon avalanche diode (SPAD) arrays has often suffered from fill factor limitations. The fill factor loss can however be recovered by employing microlenses, whereby the challenges specific to SPAD arrays are represented by large pixel pitch (> 10β
Β΅m), low native fill factor (as low as βΌ10%), and large size (up to 10 mm). In this work we report on the implementation of refractive microlenses by means of photoresist masters, used to fabricate molds for imprints of UV curable hybrid polymers deposited on SPAD arrays. Replications were successfully carried out for the first time, to the best of our knowledge, at wafer reticle level on different designs in the same technology and on single large SPAD arrays with very thin residual layers (βΌ10β
Β΅m), as needed for better efficiency at higher numerical aperture (NA > 0.25). In general, concentration factors within 15-20% of the simulation results were obtained for the smaller arrays (32Γ32 and 512Γ1), achieving for example an effective fill factor of 75.6-83.2% for a 28.5β
Β΅m pixel pitch with a native fill factor of 28%. A concentration factor up to 4.2 was measured on large 512Γ512 arrays with a pixel pitch of 16.38β
Β΅m and a native fill factor of 10.5%, whereas improved simulation tools could give a better estimate of the actual concentration factor. Spectral measurements were also carried out, resulting in good and uniform transmission in the visible and NIR
ΠΠ½Π°ΡΠ΅Π½ΠΈΠ΅ Π΄Π΅ΡΠΌΠ°ΡΠΎΠ³Π»ΠΈΡΠΈΠΊΠΈ Π² ΠΊΡΠΈΠΌΠΈΠ½Π°Π»ΠΈΡΡΠΈΡΠ΅ΡΠΊΠΎΠΌ ΠΎΠΏΠΈΡΠ°Π½ΠΈΠΈ Π²Π½Π΅ΡΠ½ΠΎΡΡΠΈ ΡΠ΅Π»ΠΎΠ²Π΅ΠΊΠ°
Based on materials of combined anthropogenic enquiry of 2 620 men and 380 women, which included fingerprint and palmprint records, relations between dermatoglyphic and descriptive external characteristics have been studied with the aid of various statistical methods. The obtained data can significantly extend capabilities of expert examination concerning the criminalistic and medicolegal anthropometric identification in operational investigations.ΠΠ° ΠΌΠ°ΡΠ΅ΡΠΈΠ°Π»Π°Ρ
ΠΊΠΎΠΌΠΏΠ»Π΅ΠΊΡΠ½ΠΎΠ³ΠΎ Π°Π½ΡΡΠΎΠΏΠΎΠΌΠ΅ΡΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΎΠ±ΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ 2 620 ΠΌΡΠΆΡΠΈΠ½ ΠΈ 380 ΠΆΠ΅Π½ΡΠΈΠ½, Π²ΠΊΠ»ΡΡΠ°ΡΡΠ΅Π³ΠΎ ΡΠ½ΡΡΠΈΠ΅ ΠΎΡΠΏΠ΅ΡΠ°ΡΠΊΠΎΠ² ΠΏΠ°Π»ΡΡΠ΅Π² ΠΈ Π»Π°Π΄ΠΎΠ½Π΅ΠΉ, Ρ ΠΏΠΎΠΌΠΎΡΡΡ ΡΠ°Π·Π»ΠΈΡΠ½ΡΡ
ΡΡΠ°ΡΠΈΡΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΌΠ΅ΡΠΎΠ΄ΠΎΠ² ΠΈΠ·ΡΡΠ΅Π½Ρ ΡΠ²ΡΠ·ΠΈ ΠΌΠ΅ΠΆΠ΄Ρ Π΄Π΅ΡΠΌΠ°ΡΠΎΠ³Π»ΠΈΡΠΈΡΠ΅ΡΠΊΠΈΠΌΠΈ ΠΈ ΠΎΠΏΠΈΡΠ°ΡΠ΅Π»ΡΠ½ΡΠΌΠΈ ΠΏΡΠΈΠ·Π½Π°ΠΊΠ°ΠΌΠΈ Π²Π½Π΅ΡΠ½ΠΎΡΡΠΈ. ΠΠΎΠ»ΡΡΠ΅Π½Π½ΡΠ΅ Π΄Π°Π½Π½ΡΠ΅ ΠΌΠΎΠ³ΡΡ ΡΡΡΠ΅ΡΡΠ²Π΅Π½Π½ΠΎ ΡΠ°ΡΡΠΈΡΠΈΡΡ Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡΠΈ ΡΠΊΡΠΏΠ΅ΡΡΠ½ΠΎΠ³ΠΎ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ Π² ΠΏΠ»Π°Π½Π΅ ΠΊΡΠΈΠΌΠΈΠ½Π°Π»ΠΈΡΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΈ ΡΡΠ΄Π΅Π±Π½ΠΎ-ΠΌΠ΅Π΄ΠΈΡΠΈΠ½ΡΠΊΠΎΠΉ ΠΈΠ΄Π΅Π½ΡΠΈΡΠΈΠΊΠ°ΡΠΈΠΈ Π»ΠΈΡΠ½ΠΎΡΡΠΈ ΠΏΡΠΈ ΠΎΠΏΠ΅ΡΠ°ΡΠΈΠ²Π½ΠΎ-ΡΠ»Π΅Π΄ΡΡΠ²Π΅Π½Π½ΡΡ
ΠΌΠ΅ΡΠΎΠΏΡΠΈΡΡΠΈΡΡ
- β¦