Modulation Transfer Function Curves Research Articles

Effect of decentration and tilt on the in vitro optical quality of monofocal and trifocal intraocular lenses.

To evaluate and compare the effect of decentration and tilt on the optical quality of monofocal and trifocal intraocular lenses (IOL). Optical quality of a monofocal IOL (AcrySof IQ SN60WF; Alcon Laboratories, Inc., USA) and a trifocal IOL (AcrySof IQ PanOptix; Alcon Laboratories, Inc., USA) was assessed using an in vitro optical bench (OptiSpheric IOL R&D; Trioptics GmbH, Germany). At apertures of 3.0mm and 4.5mm, modulation transfer function (MTF) at spatial frequency of 50 lp/mm, MTF curve and the United States Air Force (USAF) resolution test chart of the two IOLs were measured and compared at their focus with different degrees of decentration and tilt. Optical quality at infinity, 60cm and 40cm and the through-focus MTF curves were compared when the two IOLs were centered at apertures of 3.0mm and 4.5mm. Spectral transmittance of the two IOLs was measured by the UV-visible spectrophotometer (UV 3300 PC; MAPADA, China). The SN60WF and the PanOptix filtered blue light from 400 to 500nm. Both IOLs at the far focus and the PanOptix at the intermediate focus showed a decrease in optical quality with increasing decentration and tilt. The PanOptix demonstrated enhanced optical quality compared to the previous gradient at the near focus at a decentration range of 0.3-0.7mm with a 3.0mm aperture, and 0.5mm with a 4.5mm aperture, whereas other conditions exhibited diminished optical quality with increasing decentration and tilt at the focus of both IOLs. When the two IOLs were centered, the SN60WF had better optical quality at infinity, while the PanOptix had better optical quality at 60cm and 40cm defocus. The optical quality of the SN60WF exceeded that of the PanOptix at far focus, with a 3mm aperture decentration up to 0.7mm and a 4.5mm aperture decentration up to 0.3mm; this observation held true for all tilts, irrespective of aperture size. As both decentration and tilt increased, the optical quality of the SN60WF deteriorated more rapidly than that of the PanOptix at the far focal point. The SN60WF showed a decrease in optical quality with increasing decentration and tilt. Optical quality of the PanOptix at the near focus increased in some decentration conditions and decreased in some conditions, while it showed a decrease at the other focuses with increasing decentration. While tilt only had a negative effect on optical quality. When both IOLs were centered, the PanOptix provided a wider range of vision, while the SN60WF provided better far distance vision. At the far focus, the SN60WF has better resistance to tilt than the PanOptix, but the optical quality degrades more quickly when decentered and tilted.

Tolerance to decentration of biaspheric intraocular lenses with refractive phase-ring extended depth of focus and diffractive trifocal designs.

This study aimed to investigate the in vitro tolerance to decentration of biaspheric intraocular lens (IOLs) with refractive phase-ring extended depth-of-focus (EDOF) and diffractive trifocal designs. This experimental study was carried out at the Department of Optics and Optometry and Vision Science, University of Valencia, Spain. The modulation transfer function (MTF) of the ETLIO130C EDOF and the TFLIO130C trifocal IOLs (AST Products Inc., Billerica, MA, USA) were determined at different levels of decentration for a given wavelength and pupil diameter using the PMTF optical bench (Lambda-X Ophthalmics, Nivelles, Belgium). The modulation transfer function (MTF) curves, the through-focus MTF curves, and the Strehl ratios were measured at 3-mm pupil aperture for 0.25-, 0.50- and 0.75-mm decentration. The optical design of the trifocal TFLIO130C IOL is robust to small decentrations, with virtually no change in MTF response for 0.25 mm decentration. For greater decentration levels, the MTF response is slightly reduced with increasing decentration. The ETLIO130C EDOF design is robust to decentration, as the MTF response is only minimally affected when increasing the decentration up to 0.75 mm. MTF responses are slightly reduced with greater levels of decentration, but the range of focus provided by both trifocal and EDOF designs are preserved. The effects for average levels of decentration reported in the literature are minimum for both IOL designs.

Lightweight and High-Stiffness Metal Optical Systems Based on Additive Manufacturing.

To build a long-wave infrared catadioptric optical system for deep space low-temperature target detection with a lightweight and wide field of view, this work conducted a study that encompasses a local cooling optical system, topology optimization-based metal mirror design, and additive manufacturing. First, a compact catadioptric optical system with local cooling was designed. This system features a 55 mm aperture, a 110 mm focal length, and a 4-degree by 4-degree field of view. Secondly, we applied the principles of topology optimization to design the primary mirror assembly, the secondary mirror assembly, and the connecting baffle. The third and fourth modes achieved a resonance frequency of 1213.7 Hz. Then, we manufactured the mirror assemblies using additive manufacturing and single-point diamond turning, followed by the centering assembly method to complete the optical assembly. Lastly, we conducted performance testing on the system, with the test results revealing that the modulation transfer function (MTF) curves of the optical system reached the diffraction limit across the entire field of view. Remarkably, the system's weight was reduced to a mere 96.04 g. The use of additive manufacturing proves to be an effective means of enhancing optical system performance.

The Feasibility of Cylindrical Step-Wedge Phantom for Evaluating Modulation Transfer Function of CT Image : Variation of Field of View

This study aims to evaluate the modulation transfer function (MTF) from a cylindrical step-wedge phantom having diameters of 8-32 cm at various field of views (FOVs). In this study, MTF curves were measured based on the edge spread function (ESF) using IndoQCT software. In addition, noises were also measured using IndoQCT software. It was found that the MTF curve decreased as the FOV increases. The difference in the MTF 10% from FOVs of 35-50 cm was 16-20% with a p-value of 0.392. Meanwhile, the difference in MTF 50% was 16-21% with the same p-value of 0.392. It was also found that MTF curve also decreased as the phantom diameter increases. The differences in MTF 10% and 50% from phantom diameter of 8-32 cm were 6-14% and 6-16%. It is resulted that the noise level decreases as the FOV increases and the noise level also decreased as the phantom diameter increases.

Improved method for modulation transfer function measurement of Bayer color cameras

Aiming at the difficulty of detecting the modulation transfer function (MTF) of Bayer color cameras during focusing, the traditional scheme is modified in this paper. First, through analysis, it is found that the MTF of the Bayer detector decreased substantially compared to the monochromatic detector, which was caused by the loss of a large amount of light from the Bayer detector. When the MTF is calculated for the color image after de-mosaicing, the degradation of image quality leads to the inability to obtain the full-frequency MTF curve. Therefore, this paper proposes a solution to detect the MTFs of the three primary colors in the Bayer image individually, and then weight the MTFs of each primary color to obtain the MTF of the color image based on the calibration results of the light source. Then, considering the steps of differentiation and Fourier transform in the slanted-edge method, this paper solves the problem of non-uniform sampling of edge spread function by using the modification of the slanted-edge method with non-uniform Fourier transform. Finally, the optimal imaging position of a certain type of Bayer color camera is determined using the methods proposed in this paper. Simulation and test results verify the effectiveness and accuracy of the methods in this paper.

Material decomposition using dual-energy CT with unsupervised learning.

Material decomposition (MD) is an application of dual-energy computed tomography (DECT) that decomposes DECT images into specific material images. However, the direct inversion method used in MD often amplifies noise in the decomposed material images, resulting in lower image quality. To address this issue, we propose an image-domain MD method based on the concept of deep image prior (DIP). DIP is an unsupervised learning method that can perform different tasks without using a large training dataset with known targets (i.e., basis material images). We retrospectively recruited patients who underwent non-contrast brain DECT scans and investigated the feasibility of using the proposed DIP-based method to decompose DECT images into two (i.e., bone and soft tissue) and three (i.e., bone, soft tissue, and fat) basis materials. We evaluated the decomposed material images in terms of signal-to-noise ratio (SNR) and modulation transfer function (MTF). The proposed DIP-based method showed greater improvement in SNR in the decomposed soft-tissue images compared to the direct inversion method and the iterative method. Moreover, the proposed method produced similar MTF curves in both two- and three-material decompositions. Additionally, the proposed DIP-based method demonstrated better separation ability than the other two studied methods in the case of three-material decomposition. Our results suggest that the proposed DIP-based method is capable of unsupervisedly generating high-quality basis material images from DECT images.

Improved On-Orbit MTF Measurement Method Based on Point Source Arrays

The modulation transfer function (MTF) is a key characteristic used to assess the performance of optical remote sensing satellite sensors. MTF detection can directly measure a sensor’s two-dimensional (2D) point spread function (PSF); therefore, it has been applied to various high-resolution remote sensing satellites (e.g., Pleiades) using point sources. However, current point source methods mainly use 2D Gaussian functions to fit the discrete digital number (DN) of the point source on the image to extract the center of the point source and fit the PSF after encrypting multiple point sources; thus, noise robustness is poor and measurement accuracy varies widely. In this study, we developed a noise-resistant on-orbit MTF detection method based on the object space constraint among point source arrays. Utilizing object space constraint relationships among points in a point source array, a homography transformation model was established, enabling accurate extraction of sub-pixel coordinates for each point source response. Subsequently, aligning the luminosity distribution of all point sources concerning a reference point source, the encrypted PSF was obtained and then fitted to obtain the MTF. To validate the method, Gaofen-2 (GF-2) satellite images were used to conduct an in-orbit imaging experiment on the point source array of the Chinese Zhongwei remote sensing satellite calibration site. Compared with the Gaussian model methods, the proposed method yielded more accurate peak positions for each point source. Standard deviations of peak position constant ratios in along- and cross-track directions improved by 2.8 and 4.8 times, respectively. The root-mean-square error (RMSE) of the collinearity test results increased by 92%, and the noise resistance of the MTF curve improved by two times. Dynamic MTF values at the Nyquist frequency for the GF-2 panchromatic band in along- and cross-track directions were 0.0476 and 0.0705, respectively, and MTF values in different directions were well distinguished.

Comparison of astigmatism correction and visual outcomes in mix-and-match implantations of trifocal intraocular lenses with femtosecond laser-assisted arcuate keratotomy and contralateral bifocal Toric intraocular lenses.

Astigmatism reduces the postoperative visual performance after non-toric intraocular lenses (IOLs) implantation, and limits the use of refractive IOLs in cataract surgery. The purpose of this study was to compare the efficacy in astigmatism correction and the postoperative visual outcomes between the implantation of a trifocal IOL with femtosecond laser-assisted arcuate keratotomy (FSAK) in one eye and a bifocal toric IOL (TIOL) in the other, in patients with cataract and moderate astigmatism. This prospective observational paired-eye study enrolled patients with cataract and corneal astigmatism (CA) between 0.75 and 2.25 D in both eyes. The patients underwent a mix-and-match treatment comprising trifocal IOL implantation with FSAK and bifocal TIOL implantation. We compared the visual acuity (VA) at all distances, defocus curve, postoperative refractive astigmatism (RfA), CA, high-order aberrations, modulation transfer function (MTF) curve, and Strehl ratio between the two eye groups. In total, 41 patients (82 eyes) were enrolled and completed a 6-month follow-up. The 1- and 3-month uncorrected distance VA and 3-month uncorrected near VA were greater in eyes with bifocal TIOLs than with trifocal IOLs and FSAK (p = 0.036, 0.010, and 0.030, respectively), whereas the latter had greater uncorrected intermediate VA at every visit and greater VA in the intermediate range of defocus curve (at -1.50 and - 2.00 D) than the eyes with bifocal TIOLs. The postoperative RA of the eyes with trifocal IOL and FSAK was significantly higher than that of the bifocal TIOL-implanted eyes at the 3- and 6-month follow-ups. Both FSAK and TIOL implantation effectively reduce pre-existing moderate astigmatism in patients with cataract. The eyes with bifocal TIOLs had more stable long-term astigmatism correction, whereas those with trifocal IOLs and FSAK had better intermediate VA. Therefore, a mix-and-match implantation of trifocal IOL with FSAK and contralateral bifocal TIOL could achieve effective astigmatism correction and provide an overall optimal VA.

Optical Performance of a Segmented Extended-Depth-of-Focus Intraocular Lens under the Influence of Different Values of Spherical Aberration Generated by Refractive Surgery.

Corneal refractive surgery induces high-order aberrations, specifically spherical aberration (SA). These aberrations can have implications when patients later develop cataracts and require the implantation of multifocal intraocular lenses (MIOLs). MIOLs with asymmetric designs pose challenges in predicting outcomes, particularly in these cases. The aim of this study was to evaluate how different values of SA, resulting from various types of refractive surgeries, affect the optical performance of the FEMTIS Comfort intraocular lens. The through-focus modulation transfer function (TF-MTF) curve and high-contrast images of tumbling E were used as parameters to assess the optical performance of the MIOL. These parameters were measured using an adaptive optics visual simulator. Increasingly negative values of SA make the MIOL more bifocal, moderating its extended-depth-of-focus characteristic. Conversely, higher positive SA values cause the TF-MTF curve to shift towards positive vergences, leading to worsened distance vision in the +1.00 to +2.00 D range, but improved vision in the +0.50 D to +1.00 D range. Assessing SA in patients prior to implanting MIOLs with asymmetric designs is necessary for predicting outcomes and making informed decisions based on the visual requirements of patients.

Effect of postoperative residual astigmatism on visual outcomes after trifocal intraocular lens implantation.

The aim of this study was to evaluate the effect of residual astigmatism on postoperative visual outcomes after trifocal intraocular lens implantation. In this prospective observational study, we divided 156 eyes into two groups according to postoperative astigmatism measured by subjective optometry and followed them up for 3 months. Visual acuity, modulation transfer function (MTF) curves, Strehl ratio (SR), Visual Function Index-14 scores, and photic phenomena were compared. Linear regression analysis revealed a weak correlation between residual astigmatism and uncorrected distance visual acuity (UDVA) (r = 0.190, P = 0.016) at 3 months and a significant between-group difference at 1- and 3-month postoperative UDVA (P = 0.038, P = 0.018, respectively). MTF curve values and SR (MTF-10 total, MTF-10 cornea, MTF-30 total, MTF-30 cornea, SR Total, and SR cornea) were significantly worse (P < 0.001), and the Visual Function Index-14 scores were lower in the 0.5 < astigmatism ≤ 1.25 D group (P < 0.05) than in the astigmatism ≤ 0.5 D group. No significant differences were found in the frequency, severity, and bothersomeness of photic phenomena (P > 0.05). Postoperative residual astigmatism affects the UDVA of the trifocal intraocular lens-implanted eyes. Although we found no significant differences in uncorrected intermediate and near visual acuity, both objective and subjective visual quality were affected, suggesting the need for surgical planning when the anticipated postoperative astigmatism is >0.5 D.

Comparison of visual outcomes in adult patients with different types of developmental cataracts after toric multifocal intraocular lenses implantation

Purpose To analyze and compare the visual performance and patient satisfaction following the implantation of toric multifocal intraocular lenses (TMIOLs) in adult patients with different types of developmental cataracts (DC) accompanied by corneal astigmatism (CA).Methods This is a prospective observational cohort study. Patients diagnosed with DC aged 18–30 years were divided into three groups according to the anatomic location of the lens opacity: cortical, nuclear, and posterior subcapsular (PSC) groups, and implanted with TMIOLs. Visual acuity (VA), postoperative refractive astigmatism (RA), intraocular lens (IOL) rotation, high-order aberrations (HOAs), modulation transfer function (MTF) curve, and Strehl ratio were compared. The functional vision and incidence of photic phenomena were surveyed using questionnaires.Results Fifty-five eyes of 37 patients were enrolled and completed a 1-year follow-up. The mean CA was 2.06 ± 0.79 D preoperatively, and the mean RA was 0.29 ± 0.30 D 3-month postoperatively. The IOL rotation was 2.48° ± 1.89°, with no deviation > 10°. At 12 months, mean uncorrected distance VA improved from 0.93 ± 0.41 preoperatively to 0.08 ± 0.08 logarithm of the minimum angle of resolution (logMAR), mean uncorrected near VA increased from 0.45 ± 0.30 preoperatively to 0.12 ± 0.11 logMAR, and mean uncorrected intermediate VA was 0.14 ± 0.08 logMAR. The cortical and nuclear groups displayed better improvements in uncorrected near and intermediate VA than that in the PSC group. Similar results were observed in the 3-month defocus curves, HOAs, MTF curve, halo incidence, and near vision satisfaction.ConclusionIn adult patients with DC accompanied by CA, TMIOLs implantation achieved good postoperative visual outcomes and significantly reduced glasses dependency. Patients with cortical or nuclear lens opacity showed better whole-course VA and quality of vision, while patients with PSC opacity showed unsatisfactory near vision and suffered more photic phenomena.

Comparison of MTFs Measured using IndoQCT and ImQuest Software on GE CT Phantom Images

Purpose: This study aims to compare the modulation transfer function (MTF) measured using IndoQCT and ImQuest software on GE CT phantom images with variations of slice thickness and reconstruction filter. Method: This study compared MTFs measured using two software (i.e., IndoQCT and ImQuest software) on GE CT phantom images. IndoQCT implemented automatic region of interest (ROI) determination, while ImQuest used manual ROI determination. Both software analysed images with three variations of slice thickness (i.e., 2.5, 5, and 10 mm) and reconstruction filter (i.e., standard, soft tissue, chest, and bone filters). Results: IndoQCT provides automatic ROI selection and produces stable MTF curves, while ImQuest provides manual ROI selection and produces more fluctuating MTF curves. In slice thickness variation, IndoQCT showed that different slice thickness did not significantly affect spatial resolution as suggested, while ImQuest showed significant differences in spatial resolution for thickest slice thickness. In filter variation, IndoQCT produced high spatial resolution value in bone filter, while ImQuest produced the lower spatial resolution value. Overall, both software showed MTF differences within 15%, except in certain conditions, for example on a slice thickness of 10 mm. Conclusions: We have compared MTFs measured using IndoQCT and ImQuest software. Both software can be used to measure MTFs on the GE phantom images with relatively accurate results. IndoQCT generally produces higher MTF values than those from ImQuest. However, the difference MTF is not statistically significant. This study found that at 10 mm slice thickness, ImQuest produced very low MTF, while IndoQCT produced stable results for different slice thicknesses and reconstruction filters.

Analysis of the Neutron Radiographic Image Quality and Beam Intensity Produced by a Compact Multichannel Collimator

We investigate the image quality and beam intensity of thermal neutron radiography after replacing a standard single-channel neutron collimator with a compact array of microcollimators. In this study, the MCNP6 Monte Carlo computer code was used to simulate a 2 × 2-cm-area isotropic thermal neutron source, which then was collimated by an array of micron-sized neutron collimators that measured 29.8 μm in diameter and with lengths that varied from 0.6 to 3 mm. These microcollimators were spaced 30 μm apart and assembled into a 2 × 2-cm array. The image quality of the neutron beams produced by the resulting collimator arrays was assessed by imaging the edge of a very thin (~0.01-mm) gadolinium foil to obtain the image Modulation Transfer Function (MTF). The MCNP6 resulting flux map from each simulation then was converted into a grayscale .tiff image and the image’s resulting MTF obtained using the ImageJ computer program with the imaging beam geometric unsharpness, which is a limiting factor in the image resolution determined at the 10% value of the MTF curve. In this study, we found that a 2 × 2× 0.298-cm microcollimator, corresponding to a length-to–hole diameter ratio of 100:1 and a collimator length of 2.98 mm produced a beam with a geometric unsharpness of 32 μm. Compared to a standard single-channel collimator with a 2 × 2-cm aperture, the single-channel collimator would need to be 660 cm long to produce an equivalent geometric sharpness. Yet because of its shorter length, the imaging beam intensity from our 2.98-mm-thick collimator array was approximately 50 times greater than that of an equivalent single-channel collimator.

Uniform design and deep learning based liquid lens optimization strategy toward improving dynamic optical performance and lowering driving force.

An efficient optimization strategy for liquid lens combining the uniform design and the deep learning is proposed to achieve improved dynamic optical performance and lowering driving force simultaneously. The membrane of the liquid lens is designed into a plano-convex cross-section, in which the contour function of the convex surface as well as the central membrane thickness is especially optimized. The uniform design method is initially utilized to select a part of uniformly distributed and representative parameter combinations from all possible parameter range, and their performance data is then obtained through simulation using MATLAB to control COMSOL and ZEMAX. After that, a deep learning framework is employed to build a four-layer neural network with its input and output layer representing the parameter combinations and the performance data, respectively. After 5 × 103 epochs, the deep neural network has undergone sufficient training, demonstrating effective performance prediction capability for all parameter combinations. Finally, a "globally" optimized design can be obtained by setting appropriate evaluation criteria which take the spherical aberration, the coma and the driving force into consideration. Compared with the conventional design using uniform membrane thickness of 100 µm and 150 µm as well as the previously reported "locally" optimized design, distinct improvements in the spherical and the coma aberrations across the entire focal length tuning range have been achieved, whilst the required driving force is largely reduced. In addition, the "globally" optimized design exhibits the best modulation transfer function (MTF) curves and provides the best image quality.

Binocular Visual Outcomes Comparison of Two Trifocal Intraocular Lenses in High-Myopic Cataract Patients: A 1-Year Multicenter Study

To compare the postoperative visual outcomes and quality of vision obtained with 2 types of diffractive trifocal intraocular lenses (IOLs) in patients with highly myopic cataracts. Prospective, multicenter, randomized controlled trial. Patients with high-myopic cataracts were randomized to binocular implantation of either the TFNT00 (n=27) or the 839 MP (n=28) trifocal IOLs at 3 surgery centers in China and were followed up for 1 year. Postoperative uncorrected distance, uncorrected intermediate, and uncorrected near visual acuity, and best-corrected distance visual acuity were measured. The defocus curve, high-order aberrations, modulation transfer function curve, Strehl ratio, and reading ability were compared between both groups. The functional vision and incidence of photic phenomena were surveyed using questionnaires. Visual acuity at all ranges of vision was significantly improved in both groups. The TFNT00 group showed superior uncorrected intermediate visual acuity to that in the 839 MP group (P=.013). Reading ability at 40 and 60 cm was similar in both groups (P ≥ .05), whereas the preferred reading distances for near and intermediate were significantly different. The TFNT00 group had a significantly higher mean Visual Function Index 14 score, lower incidence of photic phenomena, and less posterior capsular opacity than the 839 MP group. Bilateral implantation of both types of trifocal IOLs in patients with high-myopic cataracts provided good whole-course visual restoration, although recognition of fine Chinese characters remained impeded. As compared with 839 MP IOL, TFNT00 IOL resulted in greater patient satisfaction in intermediate activities, with a lower photic phenomena incidence.

Super-resolution image reconstruction from sparsity regularization and deep residual-learned priors.

Computed tomography (CT) plays an important role in the field of non-destructive testing. However, conventional CT images often have blurred edge and unclear texture, which is not conducive to the follow-up medical diagnosis and industrial testing work. This study aims to generate high-resolution CT images using a new CT super-resolution reconstruction method combining with the sparsity regularization and deep learning prior. The new method reconstructs CT images through a reconstruction model incorporating image gradient L0-norm minimization and deep image priors using a plug-and-play super-resolution framework. The deep learning priors are learned from a deep residual network and then plugged into the proposed new framework, and alternating direction method of multipliers is utilized to optimize the iterative solution of the model. The simulation data analysis results show that the new method improves the signal-to-noise ratio (PSNR) by 7% and the modulation transfer function (MTF) curves show that the value of MTF50 increases by 0.02 factors compared with the result of deep plug-and-play super-resolution. Additionally, the real CT image data analysis results show that the new method improves the PSNR by 5.1% and MTF50 by 0.11 factors. Both simulation and real data experiments prove that the proposed new CT super-resolution method using deep learning priors can reconstruct CT images with lower noise and better detail recovery. This method is flexible, effective and extensive for low-resolution CT image super-resolution.

Enhanced Depth of Focus Intraocular Lenses: Through Focus Evaluation of Wavefront-Shaping versus Diffractive Optics

Introduction: A new class of nondiffractive, wavefront-shaping Enhanced-Depth-of-Focus (EDoF) IOLs has been introduced very recently to cope with photic phenomena known from diffractive EDoF IOLs. We investigated the through focus modulation transfer function (MTF) of two wavefront-shaping EDoF IOLs compared to an established diffractive EDoF IOL on the optical bench. Such comparison on the optical bench had not been performed before and is of high clinical importance for the cataract surgeon. Material and Methods: Tecnis Symfony (diffractive) and the wavefront-shaping Acrysof IQ Vivity and LuxSmart Crystal IOLs (22 D each) were assessed by the OptiSpheric IOL PRO 2 imaging test bench with an ISO-2 cornea and a wavelength of 546 nm. Apertures of 3 mm and 4.5 mm were applied. Results: For all three IOLs, two peaks showed up in the through focus MTF curves representing the primary and secondary focus. For Symfony, these peaks were most distinct. Power difference between far and intermediate focus was 1.25 D (Symfony), 1.75 D (Vivity), and 1.5 D (LuxSmart) with an aperture of 3 mm. With an aperture of 4.5 mm, only for LuxSmart, power difference diminished slightly to about 1 D, and only the MTF in the intermediate focus decreased for all lenses. Conclusion: For all three IOLs, we could confirm a considerable depth of focus that was most extended for Vivity. Both new wavefront-shaping IOLs had lower values of peak MTF but a markedly more continuous through focus behavior compared to the diffractive EDoF IOL.

Optical design and implementation of a compact and long focal length imaging system

In this paper, we demonstrate a compact and long focal length imaging system for building detection. This system is an all-spherical system. In order to avoid the use of aspheres, the system relies on two groups of correction elements to correct aberrations. This allows for short manufacturing cycles and simplified adjustments. The system works in the visible band from 460 nm to 750 nm. The focal length is 900 mm, and the optical length is only 280 mm. The designed modulation transfer function (MTF) is consistent with the diffraction limit. The MTF curve is 0.63 at the Nyquist frequency of 78 lp/mm. The optomechanical structure is developed based on the analysis consequence of tolerance and stray light, and a device is fabricated. We also propose a simplified method for measuring the space between the primary mirror and the secondary mirror in a compact coaxial optical system. According to the experimentation, the device is proven to meet the application requirement. Detailed descriptions of the design and implementation are provided.

Using symmetric illumination and color camera to achieve high throughput Fourier ptychographic microscopy.

This study aims to develop a high throughput Fourier ptychographic microscopy (FPM) technique based on symmetric illumination and a color detector, which is able to accelerate image acquisition by up to 12 times. As an emerging technology, the efficiency of FPM is limited by its data acquisition process, especially for color microscope image reconstruction. To overcome this, we built an FPM prototype equipped with a color camera and a 4×/0.13 NA objective lens. During the image acquisition, two symmetric LEDs illuminate the sample simultaneously using white light, which doubles the light intensity and reduces the total captured raw patterns by half. A standard USAF 1951 resolution target was used to measure the system's modulation transfer function (MTF) curve, and the H&E-stained ovarian cancer samples were then imaged to assess the feature qualities depicted on the reconstructed images. The results showed that the measured MTF curves of red, green, and blue channels are generally comparable to the corresponding curves generated by conventional FPM, while symmetric illumination FPM preserves more tissue details, which is superior to the results captured by conventional 20×/0.4 NA objective lens. This investigation initially verified the feasibility of symmetric illumination based color FPM.

Optical design of athermalized infrared dual-band annular folded lens with multilayer imaging diffractive optical elements

In order to realize the miniaturization of the infrared dual-band imaging system, a common optical path annular folded lens (AFL) with multilayer imaging diffractive optical element (MIDOE) is designed in this paper. The design principle of the AFL is studied, and the relationship between the obscuration ratio and the field of view is given. For the wide temperature range, the theoretical model of the optimal substrate materials selection for the MIDOE is established to achieve the high diffraction efficiency. According to theory analysis, the infrared dual-band AFL with IRG26-ZNS MIDOE is designed in the mid-wave infrared (MWIR) 3∼5 μm and long-wave infrared (LWIR) 8∼12 μm. The focal length is 50 mm, the equivalent F number is 1, and the full field of view is 14 ° The modulation transfer function (MTF) curves of each field of view are close to the diffraction limit when the spatial frequency is 20lps/mm, and the MTF values are greater than 0.61 and 0.28 in MWIR and LWIR, respectively. When the ambient temperature ranges from -40 °C to 80 °C, the high image quality is achieved in dual-band. In addition, the tolerance analysis is performed to verify machinability of the system. The research in this paper has important significance for the realization of a new generation of the low-cost, integrated dual-band imaging system.