Magnification System Research Articles

How to perform and interpret capillaroscopy

The essence of capillaroscopy is to examine, noninvasively and safely the morphology of nailfold dermal papillary capillaries using a magnification system (microscopical lenses). Capillaroscopy may be performed with lenses with low (×20) and with high magnification (×200 up to ×600). The video-capillaroscope consists of an optical/digital probe which is moved to the finger of the patient and allows direct contact with the nailfold. Through qualitative assessment a normal capillaroscopy can be distinguished from a pathognomonic abnormal one due most frequently to systemic sclerosis (SSc). This pattern recognition relies on evaluating the morphology of the capillaries, their density (number) and dimensions 'at sight' of the capillaries and their architecture. In SSc three progressive capillaroscopic patterns have been described ('early', 'active' and 'late'). Quantitative assessment (quantitation of certain characteristics and semi-quantitative scoring) of the capillaroscopic pictures may also be performed. Qualitative and semi-quantitative assessments are used to predict SSc clinical complications. In other connective tissue diseases (CTDs) prospective clinical studies resulting in indices which can predict future clinical complications have not been published, as yet.

Theory and tradespace analysis of a reflective axial adaptive optical zoom system

Optical zoom enables wide and narrow fields-of-view within a single optical system. Traditional zoom designs translate elements along the optical axis, a technique that is generally prohibitive for large diameter optics. Adaptive optical zoom (AOZ) alters system magnification via variable focal length elements, a technique that has the potential to facilitate zoom in large diameter systems. This paper details a novel optical theory developed to design AOZ systems. The developed theory modifies existing techniques for telescope objective design and third-order aberration determination to accommodate the additional degrees of freedom found with AOZ. The derived theory also enables a large-scale tradespace analysis, allowing optical design to begin from a broad perspective and optimize a particular design. Using the tradespace analysis, a Cassegrain AOZ objective with a 3.3Xzoom ratio is designed, demonstrating the capability and validity of the theory.

Remotely scanned multiphoton temporal focusing by axial grism scanning

A simple technique for remote scanning of the focal plane in temporal focusing multiphoton microscopy is demonstrated both theoretically and experimentally. A new on-axis light propagation optical setup design enables this scanning, which was considered not feasible in previous studies. The focal plane is axially displaced by the movement of a remote optical device, consisting of a double prism grating, and optionally a cylindrical lens. The displacement is linear, and its slope is inversely proportional to the square of the optical system's magnification.

SU-E-J-158: A Prototype of a Real-Time Respiratory Motion Monitoring System Using Microsoft Kinect Sensor.

To investigate the feasibility of a low-cost respiratory motion monitoring system based on the Microsoft Xbox Kinect sensor. We improved Kinect's inherent depth resolution from 1 cm to 1 mm via a motion magnification system. Using the Kinect software development kit, we programmed the Kinect to capture depth images and determine the average depth over a thoracic region of interest, viewed almost parallel to the subject's surface. Kinect respiratory traces (average depth vs time at a rate of 30 Hz) were acquired from four volunteers and compared with those simultaneously acquired using a commercially available strain gauge respiratory gating system. The correlation coefficient (CC) between Kinect and strain gauge traces varied from 0.958 to 0.978, with a mean CC of 0.969. This strong correlation was also demonstrated by the joint probability distribution and visual inspection. This work demonstrates the feasibility of using the Kinect for respiratory motion tracking. Traces are similar to those of a clinically used strain gauge system. The Kinect-based system provides a new and economical way to monitor respiratory motion.

A real‐time respiratory motion monitoring system using KINECT: Proof of concept

The purpose of this study is to investigate the feasibility of a low-cost respiratory motion monitoring system based on the Microsoft KINECT sensor. The authors increased KINECT's inherent depth resolution from 1 cm to 1 mm via a motion magnification system. Using the KINECT software development kit, the authors programmed the KINECT to capture depth images and determine the average depth over a thoracic region of interest, viewed almost parallel to the subject's surface. KINECT respiratory traces (average depth vs time at a rate of 30 Hz) were acquired from four volunteers and compared with those simultaneously acquired using a commercially available strain gauge respiratory gating system. The correlation coefficient (CC) between KINECT and strain gauge traces varied from 0.958 to 0.978, with a mean CC of 0.969. This strong correlation was also demonstrated by the joint probability distribution and visual inspection. It is feasible to use the KINECT for respiratory motion tracking. Traces are similar to those of a clinically used strain gauge system. The KINECT-based system provides a new and economical way to monitor respiratory motion.

Prediction and Optimization of TIG Weldment Macrostructure Zones Using Response Surface Methodology

The present work discusses the modeling and optimization of tungsten inert gas arc welding (TIG) and graphical representation of weldment macrostructure zones' shape profiles based on full factorial design of experiments and response surface modeling. To accomplish the task, an in-house developed low cost arc image magnifying system was used. The welds were produced based on a full factorial design matrix of TIG process parameters such as welding current, arc length and traverse speed. Interaction effect plots of control factors indicated weld width is affected more by the welding arc length and current. Similar effects were also observed for depth of penetration and heat affected zone (HAZ). The full factorial experimental data was further analyzed for response surface regression modeling and the response surface regression equations were tested for a number of test case data for their adequacy. The response surface regression relations were further used to optimize the TIG welding process parameters using multi response optimization technique. A mapping scheme was also developed to map the TIG weldment cross-sections' macrostructure zones including that of HAZ. The responses predicted by the surface response regression equations for the test cases were further utilized for graphical representation of the welment shape profiles including that of HAZ. The modeling methodology, regression relations and weldment mapping scheme used in the present investigation were found to be adequate for the estimation of fusion and heat affected zone boundaries.

Task-based modeling and optimization of a cone-beam CT scanner for musculoskeletal imaging.

This work applies a cascaded systems model for cone-beam CT imaging performance to the design and optimization of a system for musculoskeletal extremity imaging. The model provides a quantitative guide to the selection of system geometry, source and detector components, acquisition techniques, and reconstruction parameters. The model is based on cascaded systems analysis of the 3D noise-power spectrum (NPS) and noise-equivalent quanta (NEQ) combined with factors of system geometry (magnification, focal spot size, and scatter-to-primary ratio) and anatomical background clutter. The model was extended to task-based analysis of detectability index (d') for tasks ranging in contrast and frequency content, and d' was computed as a function of system magnification, detector pixel size, focal spot size, kVp, dose, electronic noise, voxel size, and reconstruction filter to examine trade-offs and optima among such factors in multivariate analysis. The model was tested quantitatively versus the measured NPS and qualitatively in cadaver images as a function of kVp, dose, pixel size, and reconstruction filter under conditions corresponding to the proposed scanner. The analysis quantified trade-offs among factors of spatial resolution, noise, and dose. System magnification (M) was a critical design parameter with strong effect on spatial resolution, dose, and x-ray scatter, and a fairly robust optimum was identified at M ∼ 1.3 for the imaging tasks considered. The results suggested kVp selection in the range of ∼65-90 kVp, the lower end (65 kVp) maximizing subject contrast and the upper end maximizing NEQ (90 kVp). The analysis quantified fairly intuitive results-e.g., ∼0.1-0.2 mm pixel size (and a sharp reconstruction filter) optimal for high-frequency tasks (bone detail) compared to ∼0.4 mm pixel size (and a smooth reconstruction filter) for low-frequency (soft-tissue) tasks. This result suggests a specific protocol for 1 × 1 (full-resolution) projection data acquisition followed by full-resolution reconstruction with a sharp filter for high-frequency tasks along with 2 × 2 binning reconstruction with a smooth filter for low-frequency tasks. The analysis guided selection of specific source and detector components implemented on the proposed scanner. The analysis also quantified the potential benefits and points of diminishing return in focal spot size, reduced electronic noise, finer detector pixels, and low-dose limits of detectability. Theoretical results agreed quantitatively with the measured NPS and qualitatively with evaluation of cadaver images by a musculoskeletal radiologist. A fairly comprehensive model for 3D imaging performance in cone-beam CT combines factors of quantum noise, system geometry, anatomical background, and imaging task. The analysis provided a valuable, quantitative guide to design, optimization, and technique selection for a musculoskeletal extremities imaging system under development.

Precision Calculation Algorithm and Error Analysis of Zoom Magnification Measurement

The high precise measurement for magnification of optical system of microscope has been demonstrated by using special barcode design and precise barcode image processing technologies. The magnification measurement with 50ppm accuracy is obtained. According to the measurement error estimation, the accuracy for system magnification device is about 0.06%. Barcode position is possible to reach 0.5μm for low magnification and 0.1μm for high magnification.

Su1538 Clinical Features of Early Depressed-Type Lesions and Diagnostic Significance of Endocytoscopic Classification As Well As Pit Pattern in the Colorectum

Observation of pit pattern of colorectal lesions with magnifying endoscopy is useful for qualitative diagnosis and prediction of invasion depth. The endocytoscopy, an ultra-high magnification system, can facilitate the observation of not only the structural atypia but also the cellular atypia in living colorectal lesions. We have already reported that our endocytoscopic(EC) classification corresponds well with the pathological diagnosis. Depressed type neoplasms are fairly rare, but have a prominent invasive tendency and are considered as candidates for precursors of ”de novo” cancers.

Imaging mechanisms analysis of compact digital holographic microscope for microparticles measurement

Conventional optical microscopy suffers from small depth of focus due to its high numerical aperture and magnification of the microscope objective. In comparison, digital in-line holographic microscopy (DIHM) provides information about the entire 3D volume through numerical reconstruction of the single hologram at several depths. This advantage makes DIHM an effective tool for the measurement of microparticles in suspension. Recently, our group has demonstrated the potential of DIHM for accurate measurement of particles with sizes ranging from 40 microns to a few millimetres. In this paper, the applicability of DIHM is extended for measurement of near-micron sized particles. A compact digital holographic microscope with a single microscope objective is presented. The system imaging mechanisms of the microscope is analyzed first and the recording distance of digital hologram is calculated using spatial frequency analysis. Then the system magnification, lateral resolution and depth resolution are analyzed in terms of the hologram recording distance. Finally, the characterization of microparticles with a diameter of 1 micron and 10 microns is demonstrated with the compact setup. The experimental results show the efficiency and accuracy of this method with a measured error less than 1.55% in the diameter of certified particles.

Microvascular anastomosis at 30-50× magnifications (super-microvascular anastomosis) in neurosurgery

Background:We report a safe and precise technique of microvascular anastomosis at higher magnifications (30 – 50 ×) in neurosurgery and evaluate our experiences to examine the utility of this method for cerebral revascularization in various situations.Methods:A retrospective review was carried out of patients who underwent microvascular anastomosis using a high-magnified operating microscope. This method was performed in 30 patients with 35 microvascular anastomoses in various situations. This microscope has two optical systems, a standard zooming system and a newly developed high magnification system. High resolution and good depth of focus are achieved by a new lens design in the optical system, which makes the image of the object very clear at higher magnifications. In this operating microscope, the combination of a 10 × eyepiece and the 200, 250, and 300-mm objective lens enables a range of final magnifications from 2.9 × to 50.4 ×.Results:This method enabled one to pay attention to performing atraumatic manipulations of small vessels and correct suturing, intima-to-intima, of vessel walls. Microvascular anastomoses were performed safely and precisely at higher magnifications. All anastomoses were patent.Conclusion:It is obvious that practical final magnifications of more than 30 × in neurosurgery would be super-magnified operative views. Microvascular anastomosis at 30 – 50 × magnifications (super-microvascular anastomosis) can help neurosurgeons to improve their skills, with good visualization, and to be safe and accurate when conducting cerebral revascularization in various situations.

Enlarging lens design with f-Θ lens for real time laser lithography inspections

An enlarging lens, composed of a charge-coupled-device (CCD) lens and an f-Θ lens, has been designed for real time laser lithography visual inspection purposes. The object of this design is to enlarge the image of the working specimens in real time, which used to be done by an independent magnifying system after the lithography process. F-Θ lens has both roles in this design, being a laser lithography lens and a specimen imaging lens. A beam splitter has been inserted between the f-Θ lens and the CCD lens, which divides the UV laser beam and the visible beam to form a coaxial system. This design also reaches the image requirements in both wavelength bands, that the value of MTF is nearly diffraction-limit in UV wavelength and greater than 0.45 at 40 c/mm in visible wavelength.

A new practical model of an objective lens with assembling clearance for transmission electron microscope

A new objective lens model including magnetic pole pieces, coil windings, magnetic circuit as well as the assembling clearance between the pole piece and magnetic circuit is developed to obtain high simulation precision. The calculation is based on the second-order finite element method (SOFEM) with the measured B– H magnetization curves of the lens materials. The magnetic pole pieces and magnetic circuit are firstly optimized to reduce the lens saturation and obtain minimum spherical aberration coefficient, then modified to release the magnetic flux leakage caused by the increased clearance. In the end, an example is given for a 200 kV TEM with the point resolution of 0.25 nm and off-axis aberration coefficients at the image plane are calculated for dynamic correction. Results show that the magnetic circuit is unsaturated and the saturated area is only 0.8×4.8 mm 2 around the lower pole piece with a maximum magnetic flux density of 2.537 T. This model can reduce the magnetic flux leakage and obtain the point resolution with smaller excitation. The calculation also shows that the off-axis aberrations require correcting dynamically to acquire fine image quality under low system magnification.

Investigation of the Spatial Resolution and Field of View with Change of Magnification in VRX CT

Introduction: Variable resolution x-ray (VRX) CT is a new type of CT that can image objects at various spatial resolutions. In a VRX CT scanner, the spatial resolution increases at the cost of reduction in the field of view (FOV). An important factor that limits the spatial resolution of the VRX CT is the effect of focal spot size. Also, the optimum magnification is different at each incident angle. Material and Methods: To investigate the spatial resolution and the FOV in VRX CT, we used the numerical parameters of an actual VRX CT scanner. The effects of decreasing the focal spot size and optimizing magnification on the spatial resolution and the FOV of the system were studied theoretically. Results: The focal spot size was found to greatly limit the spatial resolution of the VRX CT at the small incident angles. By decreasing the focal spot size, the spatial resolution was comparatively improved. Optimization of the system magnification without decreasing the focal spot size could greatly increase the spatial resolution of the system. After optimization of magnification, the FOV of the system decreased significantly. Discussion and Conclusion: The spatial resolution of the system after optimizing the magnification increased from 7.5 to more than 35 cycles/mm and also the effect of the focal spot no longer limited the spatial resolution at incident angles smaller than 13˚. The disadvantage of optimization of magnification was a great decrease in the FOV of the system. The optimization of magnification has the reverse effect on the spatial resolution and the FOV of the system so at each incident angle, according to the importance of spatial resolution or FOV, the system magnification can be set to lead to the desirable condition.

New installation scheme for viscoelastic dampers using cables

Passive energy dissipation devices, such as, viscous, viscoelastic, and friction devices are generally installed in buildings using diagonal or chevron braces. To increase the effective damping force and to reduce the damper volume, various magnifying system of the damper displacement, such as, toggle brace system and scissor-jack-damper configuration have been developed with increase in installation cost. In this study, new installation scheme for passive dampers was proposed using cables installed in such a way that relative displacement equal to storey displacement occurs between the cable and the structure when the structure is subjected to lateral load. The cables can be installed continuously or discretely between base and top storey of the structure. To verify the validity of the proposed method nonlinear dynamic analysis of model structures with viscoelastic dampers installed using the proposed configuration scheme was carried out using three earthquake records and two sinusoidal forces. According to the analysis, the proposed method resulted in significant reduction in the size of dampers compared with the conventional installation methods.

S1620: Real Time Diagnosis in the Colorectum With Integrated Type Endocytoscope

We have reported usefulness of magnifying colonoscopy with which we can predict the histological type of a lesion or the depth of a cancer according to its surface microstructure (pit pattern).Endocytoscopy (EC), an ultra-high magnification system, enables us to observe not only the structural atypia but also cellular atypia in the colorectal lesions. The first prototype was a probe type, but an integrated type which enables in vivo ordinary view, low power magnification up to x80, and high power magnification of x450 was developed in 2005.

Implantable miniature telescope: Lessons learned

Background The Implantable Miniature Telescope (IMT™) is a telescopic prosthesis that, combined with the optics of the cornea, constitutes an intraocular magnifying system. It is indicated for use in patients with stable, nonfoveal sparing, bilateral, stable, age-related macular degeneration (end-stage) with associated scotomas. The telescope prosthesis is implanted in only one of the patient's eyes. In this way, the implanted eye provides improved visual acuity, and the nonimplanted eye continues to provide peripheral vision for ambulation. Two hundred seventeen patients with end-stage AMD were enrolled in a prospective, multicenter, open-label trial (IMT-002) beginning in 2003. The implanted eye was the worse eye for most patients based on a selection rule set by the U.S. Food and Drug Administration (FDA) protocol; however, in most cases (90%), visual acuity improvement goals were met with the device. This report will retrospectively look at 2 selected patients implanted at the Emory Eye Center in Atlanta as part of that trial to derive lessons for subject and eye selection criteria. Case Reports Two cases were selected to represent patients' levels of functional success and satisfaction. Determination of their visual and functional outcome at 1-year postimplantation was based on best-corrected visual acuity and the National Eye Institute Visual Functioning Questionnaire 25-Item quality-of-life survey. Four years after implantation, 1 patient continued to use the telescope prosthesis eye for all visual activities; the other patient did not perceive any benefit from the device and continued to primarily use the fellow nonimplanted eye. The benefit of the telescopic prosthesis was most likely accounted for by the level of visual acuity in both eyes postimplantation and eye dominance. Conclusion Proper eye selection chosen for implantation with the telescope prosthesis appears to be an important if not critical factor in determining patient satisfaction for visual processing and functional success. Based on the author's experience with the IMT, optometrists can aid the multidisciplinary team by preoperatively determining which eye, if implanted, offers the optimal potential functional benefit for appropriate candidates.

High resolution in vivo micro-CT with flat panel detector based on amorphous silicon

A high-resolution in vivo micro-CT system for combining with fluorescence molecular tomography (FMT), was constructed and applied in small animal imaging. The fast scanning micro-CT system designed to provide high-resolution anatomic information and reconstruction priors, consisted of a flat panel detector (FPD) based on amorphous silicon (a-Si) and a micro-focus x-ray tube. The Feldkamp algorithm was adopted in image reconstruction with graphic processing unit (GPU). The system spatial resolution of 13 lp/mm was achieved when the diameter of image field was 6 cm with the system magnification factor of 4. No obvious beam hardening artifact was observed in transaxial image of a water phantom after correction. The contrast-to-noise ratio (CNR) study of various tissue phantoms was also presented. The in-vivo imaging of an anesthetic mouse was performed to demonstrate the feasibility of our system.

Size measurement in endoscopic images by low coherence interferometry

We present a novel optical sensor that is able to measure the real dimensions and areas of anatomical objects in endoscopic images by taking advantage of the knowledge of the real distance from the endoscope tip to the anatomical wall under examination. At present the major obstacle to quantitative endoscopy is the inability of calibrating the acquired images because of the magnification system. In order to solve this problem in a satisfactory way we have studied and realized a new system combining an imaging system, applied to a clinical endoscope, with an absolute distance sensor based on fiber optic low coherence interferometry (FOLCI). Up to now the sensor has been tested on pig trachea, simulating the real humidity and temperature (37 °C) conditions. The sensor show high sensitivity, providing correct measurements of the size of biological samples even in the case of very low reflected power (down to 2–3 nW).

Proposal for measuring the quantum states of neutrons in the gravitational field with a CCD-based pixel sensor

An experimental setup is proposed for the precise measurement of the quantum states of ultracold neutrons bound in the earth's gravitational field. The experiment utilizes a CCD-based pixel sensor and magnification system to observe the fine structure of the neutron distribution. In this work, we analyzed the sensor's deposited energy measurement capability and found that its spatial resolution was 5.3 μ m . A magnifying power of two orders of magnitude was realized by using a cylindrical rod as a convex mirror.