Measuring the retina optical properties using a structured illumination imaging system

2011 ◽  
Author(s):  
A. Basiri ◽  
T. A. Nguyen ◽  
M. Ibrahim ◽  
Q. D. Nguyen ◽  
Jessica C. Ramella-Roman
Keyword(s):  
Optical Properties ◽  
Imaging System ◽  
Structured Illumination

scholarly journals Bionic Birdlike Imaging Using a Multi-Hyperuniform LED Array

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4084
Author(s):  
Xin-Yu Zhao ◽  
Li-Jing Li ◽  
Lei Cao ◽  
Ming-Jie Sun
Keyword(s):  
Imaging System ◽  
Color Image ◽  
Digital Camera ◽  
Frame Rate ◽  
Digital Cameras ◽  
Structured Illumination ◽  
Pixel Resolution ◽  
Led Array ◽  
Frequency Aliasing ◽  
Imaging Sensors

Digital cameras obtain color information of the scene using a chromatic filter, usually a Bayer filter, overlaid on a pixelated detector. However, the periodic arrangement of both the filter array and the detector array introduces frequency aliasing in sampling and color misregistration during demosaicking process which causes degradation of image quality. Inspired by the biological structure of the avian retinas, we developed a chromatic LED array which has a geometric arrangement of multi-hyperuniformity, which exhibits an irregularity on small-length scales but a quasi-uniformity on large scales, to suppress frequency aliasing and color misregistration in full color image retrieval. Experiments were performed with a single-pixel imaging system using the multi-hyperuniform chromatic LED array to provide structured illumination, and 208 fps frame rate was achieved at 32 × 32 pixel resolution. By comparing the experimental results with the images captured with a conventional digital camera, it has been demonstrated that the proposed imaging system forms images with less chromatic moiré patterns and color misregistration artifacts. The concept proposed verified here could provide insights for the design and the manufacturing of future bionic imaging sensors.

scholarly journals A Multimodal Adaptive Super-Resolution and Confocal Microscope

2018 ◽  
Author(s):  
Liyana Valiya Peedikakkal ◽  
Andrew Furley ◽  
Ashley J. Cadby
Keyword(s):  
Imaging System ◽  
Imaging Modality ◽  
Super Resolution ◽  
Single Mode ◽  
Imaging Modalities ◽  
Structured Illumination ◽  
Wide Range ◽  
Transition Times ◽  
Localisation Microscopy ◽  
Microscopy Techniques

Existing optical microscopy techniques compromise between resolution, photodamage, speed of acquisition and imaging in to deep samples. This often confines a technique to a certain biological system or process. We present a versatile imaging system which can switch between imaging modalities with sub millisecond transition times to adapt to the needs of a wide range of sample types. The imaging modalities provide the minimally invasive but low-resolution epi-fluorescence though increasing invasive but higher resolution confocal and structured illumination until the highest resolution is achieved through the most intrusive, localisation microscopy. The ability of the system to overcome the limitations of conventional single mode microscopy is demonstrated by several biological investigations. The ideas presented in this work allow researchers to move away from the model of a single imaging modality to study a specific process and instead follow those processes using the most suitable method available during the lifetime of the investigation.

Verification of Long-Range MTF Testing Through Intermediary Optics

2020 ◽  
Vol 2020 (9) ◽  
pp. 346-1-346-7
Author(s):  
Alexander Schwartz ◽  
Sarthak Tandon ◽  
Jackson Knappen
Keyword(s):  
Optical Properties ◽  
Long Range ◽  
Real World ◽  
Imaging System ◽  
Imaging Systems ◽  
Depth Of Field ◽  
Use Case ◽  
Production Environment ◽  
Simulated Test ◽  
Working Distance

Measuring the MTF of an imaging system at its operational working distance is useful for understanding the system’s use case performance. However, it is often not practical to test imaging systems at long distances (several meters to infinity), particularly in a production environment. Intermediate optics (relay lenses) can be used to simulate longer test distances. The Imatest Collimator Fixture is a machine developed for testing imaging systems at specified simulated distances up to infinity through the use of a relay lens and a test chart. The relay lens’s optical properties dictate the required distance between the optic and the test chart, or Collimator Working Distance (WDC), to project the correct simulated distance (SD). This paper provides a method for validating the accuracy of simulated test distances. Successful validation is achieved when the distances at which peak MTF occurs in the real world match the simulated distances at which peak MTF occurs on the collimator fixture, or if both distances are within the depth of field (DoF) of the imaging system in use.

The LENSAR® Laser System–fs 3D for Femtosecond Cataract Surgery

2014 ◽  
Vol 08 (02) ◽  
pp. 93 ◽  
Author(s):  
Mark Packer ◽  
Stephen D Klyce ◽  
Craig Smith ◽  
◽  
◽  
...  
Keyword(s):  
Cataract Surgery ◽  
Imaging System ◽  
Intraoperative Imaging ◽  
Full Range ◽  
Laser System ◽  
Structured Illumination ◽  
Operating Environment ◽  
High Definition ◽  
Corneal Incision ◽  
Safety Margins

The LENSAR® Laser System’s ergonomic design permits flexible functionality in any operating environment. Its low-pressure liquid interface eliminates corneal compression and facilitates accurate and complete capsulotomy construction. The Augmented Reality™ imaging system utilises a variable super luminescent diode for scanning structured illumination to provide high-contrast, high-definition targets, which guide the laser. Real-time imaging adjustments compensate for minute degrees of tissue displacement, permitting unrivalled precision in corneal incision architecture. Precise laser spot application allows fragmentation of all grades of cataract, without the need for unnecessarily large safety margins. Iris registration compensates for cyclotorsion in the construction of arcuate incisions by aligning preoperative corneal biometry to intraoperative imaging. The ability to define the cataract grade intraoperatively facilitates efficient phacofragmentation by permitting surgeon-specified preset patterns for the full range of nuclear densities. The LENSAR Laser System represents the state of the art in femtosecond cataract surgery.

Time-resolved imaging of fluorescent inclusions in optically turbid medium — phantom study

2010 ◽  
Vol 18 (1) ◽  
Author(s):  
M. Kacprzak ◽  
A. Liebert ◽  
P. Sawosz ◽  
N. Żołek ◽  
D. Milej ◽  
...  
Keyword(s):  
Optical Properties ◽  
Imaging System ◽  
Single Photon ◽  
Photon Counting ◽  
Turbid Medium ◽  
Time Resolved ◽  
Excitation Light ◽  
Time Resolved Imaging ◽  
Fish Tank ◽  
Surrounding Liquid

AbstractWe present results of application of a time-resolved optical system for imaging of fluorescence excited in an inclusion containing indocyanine green (ICG), and located in optically turbid medium. The developed imaging system enabled simultaneous acquisition of fluorescence and diffusive reflectance. Eight independent time-resolved measurement channels based on time-correlated single photon counting technique were applied. In four of these channels, used for the fluorescence detection, sets of filters were applied in order to block the excitation light. Fast optomechanical switches allowed us to illuminate sequentially nine different spots on the surface of the studied object and finally 4×4 pixels maps at excitation and emission wavelengths were obtained. A liquid phantom used in this study consists of the fish tank filed with a solution ofmilk and water with black ink added to obtain optical properties in the range of the optical properties typical for the living tissue. A gel ball of a diameter of 5 mm with precisely controlled concentration of ICG was immersed in the liquid. The measurements were performed for inclusion located at different depths and for various ICG concentrations in the gel ball and in the surrounding liquid. The recorded distributions of times of arrival (DTA) of fluorescence photons and times of flight (DTOF) of diffusely reflected photons were analyzed by calculation of their statistical moments. We observed specific changes in moments of the measured DTAs as a function of depth of immersion of the fluorescent inclusion in the medium. We noted also that the changes of moments depend significantly on concentration of the dye in the fluorescence inclusion as well as in the surrounding liquid.

A 3-D fluorescence imaging system incorporating structured illumination technology

2010 ◽  
Author(s):  
L. Antos ◽  
P. Emord ◽  
B. Luquette ◽  
B. McGee ◽  
D. Nguyen ◽  
...  
Keyword(s):  
Fluorescence Imaging ◽  
Imaging System ◽  
Structured Illumination ◽  
Fluorescence Imaging System

scholarly journals Extended mechanical force measurements using structured illumination microscopy

2021 ◽  
Vol 379 (2199) ◽  
Author(s):  
Kseniya Korobchevskaya ◽  
Huw Colin-York ◽  
Liliana Barbieri ◽  
Marco Fritzsche
Keyword(s):  
Imaging System ◽  
Three Dimensional ◽  
Traction Force ◽  
Super Resolution ◽  
Mechanical Force ◽  
Structured Illumination ◽  
Structured Illumination Microscopy ◽  
Biological Studies ◽  
Wide Range ◽  
Spatio Temporal

Quantifying cell generated mechanical forces is key to furthering our understanding of mechanobiology. Traction force microscopy (TFM) is one of the most broadly applied force probing technologies, but its sensitivity is strictly dependent on the spatio-temporal resolution of the underlying imaging system. In previous works, it was demonstrated that increased sampling densities of cell derived forces permitted by super-resolution fluorescence imaging enhanced the sensitivity of the TFM method. However, these recent advances to TFM based on super-resolution techniques were limited to slow acquisition speeds and high illumination powers. Here, we present three novel TFM approaches that, in combination with total internal reflection, structured illumination microscopy and astigmatism, improve the spatial and temporal performance in either two-dimensional or three-dimensional mechanical force quantification, while maintaining low illumination powers. These three techniques can be straightforwardly implemented on a single optical set-up offering a powerful platform to provide new insights into the physiological force generation in a wide range of biological studies. This article is part of the Theo Murphy meeting issue ‘Super-resolution structured illumination microscopy (part 1)'.

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