Analog Image Research Articles

Broadband and parallel multiple-order optical spatial differentiation enabled by Bessel vortex modulated metalens

Optical analog image processing technology is expected to provide an effective solution for high-throughput and real-time data processing with low power consumption. In various operations, optical spatial differential operations are essential in edge extraction, data compression, and feature classification. Unfortunately, existing methods can only perform low-order or selectively perform a particular high-order differential operation. Here, we propose and experimentally demonstrate a Bessel vortex modulated metalens composed of a single complex amplitude metasurface, which can perform multiple-order radial differential operations over a wide band by presetting the order of the corresponding Bessel vortex. This architecture further enables angle multiplexing to create multiple information channels that synchronously perform multi-order spatial differential operations, indicating the superiority of the proposed devices in parallel processing. Our approach may find various applications in artificial intelligence, machine vision, autonomous driving, and advanced biomedical imaging.

Journalistic Images: Contemporary Challenges for Visual Research in Digital Journalism

This article aims to identify contemporary challenges in researching digital journalism images and propose potential outcomes for addressing these challenges. We argue that the analysis of contemporary journalistic photography requires a departure from traditional approaches used for analog images. Instead, it should be viewed within the ever-changing digital ecosystem in which digital journalism circulates and the new forms of creating, sharing, and visualizing its content that arise from platform context and mobile consumption. We have divided these challenges into two categories: the first relates to topics associated with the studied object, and the second pertains to the research process itself. On the one hand, changes in the nature of the photographic medium, its transmission and profusion potentials, shifts in journalistic workflow and labor relations, evolving professional multimedia needs, audience participation, and new forms of consumption are some of the aspects that need to be considered. On the other hand, we also must deal with the ephemeral quality of digital objects and recognize that researching digital objects is inherently intertwined with understanding the digital ecosystem in which these objects exist. Finally, we identify the digital methods-oriented approach as a potential path to addressing these challenges, mainly because of its characteristics of following and adapting to the medium’s logic

Emissive Guanosine Analog Applicable for Real-Time Live Cell Imaging.

A new emissive guanosine analog CF3thG, constructed by a single trifluoromethylation step from the previously reported thG, displays red-shifted absorption and emission spectra compared to its precursor. The impact of solvent type and polarity on the photophysical properties of CF3thG suggests that the electronic effects of the trifluoromethyl group dominate its behavior and demonstrates its susceptibility to microenvironmental polarity changes. In vitro transcription initiations using T7 RNA polymerase, initiated with CF3thG, result in highly emissive 5'-labeled RNA transcripts, demonstrating the tolerance of the enzyme toward the analog. Viability assays with HEK293T cells displayed no detrimental effects at tested concentrations, indicating the safety of the analog for cellular applications. Live cell imaging of the free emissive guanosine analog using confocal microscopy was facilitated by its red-shifted absorption and emission and adequate brightness. Real-time live cell imaging demonstrated the release of the guanosine analog from HEK293T cells at concentration-gradient conditions, which was suppressed by the addition of guanosine.

Two-dimensional optical multiple-order differentiations based on spatial spectrum modulation.

Optical differential operations have recently attracted considerable attention owing to the capabilities of ultrafast speed and low power consumption. The transfer function, which embodies the frequency-domain characteristics of differential systems, plays an important role in differentiator design. Here, we report a super-Gaussian aperture differential filter, and we reveal unique characteristics of odd- and even-order transfer functions and corresponding differential effects via spatial spectrum modulation. We show that the feature of the transfer function is well maintained, and more precise differentiation can be achieved using the designed filter. Two-dimensional first- to fifth-order full and partial differentiations are implemented both theoretically and experimentally. Our work provides an approach for engineering customized multiple-order differentiators and promotes the advancements of related areas such as optical analog computing and image processing.

Safety, tolerability and efficacy of 212Pb-DOTAMTATE as a targeted alpha therapy for subjects with unresectable or metastatic somatostatin receptor-expressing gastroenteropancreatic neuroendocrine tumors (SSTR+ GEP-NETs): A phase 2 study.

4020 Background: 212Pb-DOTAMTATE is a Targeted Alpha Therapy (TAT) in clinical development for subjects with SSTR+ neuroendocrine tumors. A phase I dose-escalation study has already been completed (Delpassand et al. J Nucl Med 2022). TAT holds the promise to improve outcomes versus Peptide Receptor Radionuclide Therapy (PRRT) with beta-emitters like 177Lu-DOTATATE, currently considered the standard of care for subjects with GEP-NETs. Methods: ALPHAMEDIX 02 is a Phase II, open-label, multicenter study evaluating the safety, tolerability and efficacy of 212Pb-DOTAMTATE in PRRT-naïve (Cohort 1, N = 36) and PRRT-refractory (Cohort 2, Target N = 30) subjects with histologically confirmed unresectable or metastatic GEP-NETs, positive somatostatin analogue imaging and at least 1 site of measurable disease per RECIST 1.1. 212Pb-DOTAMTATE was administered at 67.6 μCi/kg per cycle, with a maximum activity administered per cycle of 5.5 mCi every 8 weeks, for up to 4 cycles. Primary endpoints include overall response rate (ORR) per RECIST1.1, and incidence and severity of adverse events (AEs). Secondary endpoints include progression free survival, overall survival , and health-related quality of life. Initial results of the already completed cohort 1 are presented. Results: In cohort 1, 17 out of 36 subjects with metastatic SSTR+ GEP-NETs achieved a confirmed response (ORR 47.2% (32.0-63.0%)). In the Phase I trial, five out of eight PRRT- naïve subjects with SSTR+ GEP-NETs treated with the same regimen of 212Pb-DOTAMTATE achieved a response (ORR 62.5% (30.6-86.3%)): the combined ORR from both studies is 50% (22 out of 44, 95%-CI:36% - 64%). Median Duration of Response (DOR) has not been reached in both studies. Four out of five subjects (80%) with confirmed response in Phase I had a DOR of ≥ 12 months. In the ongoing Phase II study the response follow-up for 10 subjects with confirmed response is currently shorter than 6 months: so far 7 out of 17 subjects (41%) with confirmed response had a DOR of ≥ 6 months, and one of these subjects had a DOR of ≥ 12 months. Lymphocytopenia is a lead cause of the 59% grade 3 and 4 AEs reported in subjects in cohort 1. Overall, 4 fatal AEs were reported: death / progressive disease (N = 2), carcinoid syndrome (N = 1) and sepsis (N = 1). Conclusions: In PRRT-naïve subjects with SSTR+ unresectable or metastatic GEP-NETs treatment with up to 4 cycles of ²¹²Pb-DOTAMTATE (67.6 μCi/kg/cycle) was well-tolerated, with a safety profile consistent with the underlying disease and expected toxicities of radioligand therapy, similar to 177Lu-DOTATATE. The ORR of 47.2% in cohort 1 (50% in the pooled dataset) appears to be substantially higher than the ORR previously reported for 177Lu-DOTATATE in the pivotal NETTER-1 study (ORR 18% (10–25%)). Clinical trial information: NCT05153772 .

Ultra-Efficient Low-Power Retinal Nano Electronic Circuit for Edge Enhancement and Detection Using 7 nm FinFET Technology

Ultra-Efficient Low-Power Retinal Nano Electronic Circuit for Edge Enhancement and Detection Using 7 nm FinFET Technology

The medium modulates the medusa effect: Perceived mind in analogue and digital images

We effortlessly attribute mental states to other people. We also attribute minds to people depicted in pictures, albeit at a reduced strength. Intriguingly, this reduction in intensity continues for images of people within a photograph itself—a phenomenon known as the Medusa effect. The present study replicates the Medusa effect for images shown digitally and on paper. Crucially, we demonstrate that we can reduce the magnitude of the Medusa effect by depicting people digitally within a computer screen (e.g., as if one were interacting with a person on a Zoom call). As well as modulating the quantity of the Medusa effect, changes in pictorial medium can affect the quality of the perceived mind. Specifically, the dimension of Experience—what a depicted person can feel—reflected participants' observations that they could interact with an onscreen person embedded in a digital image. This combination of a robust Medusa effect and the ability to control it both quantitatively and qualitatively opens many avenues for its future application, such as manipulating and measuring mind in immersive media.

Reconfigurable image processing metasurfaces with phase-change materials.

Optical metasurfaces have enabled analog computing and image processing within sub-wavelength footprints, and with reduced power consumption and faster speeds. While various image processing metasurfaces have been demonstrated, most of the considered devices are static and lack reconfigurability. Yet, the ability to dynamically reconfigure processing operations is key for metasurfaces to be used within practical computing systems. Here, we demonstrate a passive edge-detection metasurface operating in the near-infrared regime whose response can be drastically modified by temperature variations smaller than 10 °C around a CMOS-compatible temperature of 65 °C. Such reconfigurability is achieved by leveraging the insulator-to-metal phase transition of a thin layer of vanadium dioxide, which strongly alters the metasurface nonlocal response. Importantly, this reconfigurability is accompanied by performance metrics-such as numerical aperture, efficiency, isotropy, and polarization-independence - close to optimal, and it is combined with a simple geometry compatible with large-scale manufacturing. Our work paves the way to a new generation of ultra-compact, tunableand passive devices for all-optical computation, with potential applications in augmented reality, remote sensing and bio-medical imaging.

Long-term monitoring of desert restoration processes using historical stereoscopic imagery and laser scanning data: An example of the Błędów Desert (Poland)

This study aimed to present the spatiotemporal changes associated with the loss and subsequent regaining of the original character of the Błędów Desert (Poland) as a result of restoration efforts. The study area is one of the few places in Europe with a sandy desert character. The research period covered nearly 40 years, covering an area of approximately 1400 ha.The methodology is based on comparing the height structure parameters by analyzing point clouds created from contemporary and historical stereoscopic images. For this purpose, four sets of stereoscopic images were used, including two historical analog images from 1982 to 1996 and contemporary digital data from 2012 to 2018. Additional datasets such as airborne laser scanning data and cadastral databases were used as auxiliary data. The results showed an increase in the area covered by tall vegetation from 2% in 1982 to 18% and 41% in 1996 and 2012, respectively, which decreased to 30% after the completion of restoration activities in 2018. The restoration process has enabled the revival of the original desert character of the study area, although the total area covered by sand decreased compared to its state in the early 1980s. These results indicate the significant potential of the presented methodology in supporting ecosystem management systems, where changes in the height structure of vegetation play a crucial role. This applies to monitoring land abandonment, forest management, and large-scale reclamation work.

Отдаленные результаты использования системы трехмерной визуализации в сравнении со стандартной аналоговой визуализацией в хирургии хрусталика

Abstract Long-term results of using a three-dimensional imaging system in comparison with standard analog imaging in lens surgery A.V. Zhuravlev, V.S. Stebnev, S.D. Stebnev, I.V. Malov, L.M. Nizamutdinova Samara State Medical University, Department of Eye Diseases, Department of Eye Diseases IPO, Samara, Russian Federation Eye Surgery LLC, Samara, Russian Federation Purpose. Assessment of the safety and effectiveness of lens surgery using three-dimensional visualization based on the analysis of long-term results of operations. Material and methods. The study involved 500 patients (500 eyes). The main group consisted of 250 patients with cataracts operated by phacoemulsification using the NGENUITY three-dimensional digital imaging system. The control group consisted of 250 patients using analog imaging, i.e. using standard eyepieces. Long-term results were evaluated 3, 6 and 12 months after surgery using parameters such as uncorrected and maximally corrected visual acuity, refractometry indicators and corneal endothelial cell density. Results. Although in the long-term period we did not record statistically significant differences between the achieved indicators of visual acuity, refractometry and density of corneal endothelial cells in the main and control groups, their average values were still slightly higher in the group of patients where three-dimensional digital imaging was used in the FEC process. Conclusion. The long-term results of a comparative study of visual acuity, endothelial cell density, spherical and cylindrical components of refraction when using analog and three-dimensional digital imaging in cataract surgery allow us to conclude that the latter method is still more effective than the standard one. All this, combined with great ergonomic capabilities, makes it possible to recommend three-dimensional digital visualization for wider dissemination in clinical practice. Key words:cataract surgery, three-dimensional digital visualization, standard analog visualization, visual acuity, refraction, density of endothelial cells

Digitizing Historical Aerial Images: Evaluation of the Effects of Scanning Quality on Aerial Triangulation and Dense Image Matching

In the last decade, many aerial photographic archives have started to be digitized for multiple purposes, including digital preservation and geoprocessing. This paper analyzes the effects of professional photogrammetric versus consumer-grade scanners on the processing of analog historical aerial photographs. An image block over Warsaw is considered, featuring 38 photographs acquired in 1986 (Wild RC10, Normal Aviogon II lens, 23 × 23 cm format) with a ground sampling distance (GSD) of 4 cm. Aerial triangulation (AT) and dense image matching (DIM) procedures are considered, analyzing how scanning modalities are important in the massive digitization of analog images for georeferencing and 3D product generation. The achieved results show how consumer-grade scanners, unlike more expensive photogrammetric scanners, do not possess adequate recording quality to ensure high accuracy and geometric precision for geoprocessing purposes. However, consumer-grade scanners can be used for time and cost-efficient applications where a partial loss of data quality is not critical.

Digital Templating of Hip Arthroplasty Using Microsoft PowerPoint: A Pilot Study with Technical Details.

Templating is essential in hip arthroplasty preparation, facilitating implant size prediction and surgical rehearsal. It ensures the selection of suitable implants according to patient anatomy and disease, aiming to minimize post-operative complications. Various templating methods exist, including traditional acetate templating on both analog and digital images, alongside digital templating on digital images, which is categorized into 2D and 3D approaches. Despite the popularity of acetate templating on digital images, challenges such as the requirement for physical templates and result preservation persist. To address these limitations, digital templating with software like OrthoSize and Orthoview has been suggested, although not universally accessible. This technical note advocates for Microsoft PowerPoint as an effective alternative for 2D digital templating, highlighting its user-friendly features for image manipulation without needing specialized software. The described method involves scanning acetate templates, adjusting the images in PowerPoint 365 for size, position, and calibration on patient radiographs, and demonstrating reliability through preliminary assessments, with intraclass correlation coefficient (ICC) values indicating a high level of agreement for cup and stem size (ICC = 0.860, 0.841, respectively) but moderate for neck length (ICC = 0.592). We have introduced a method for performing 2D digital templating in the clinical field without the need for specialized software dedicated to digital templating. We believe this method significantly improves the accessibility to 2D digital templating, which was previously limited by the need for digital templating software. Additionally, it enables surgeons to easily establish arthroplasty plans and share them, overcoming the limitations of acetate templates.

Descanning: From Scanned to the Original Images with a Color Correction Diffusion Model

A significant volume of analog information, i.e., documents and images, have been digitized in the form of scanned copies for storing, sharing, and/or analyzing in the digital world. However, the quality of such contents is severely degraded by various distortions caused by printing, storing, and scanning processes in the physical world. Although restoring high-quality content from scanned copies has become an indispensable task for many products, it has not been systematically explored, and to the best of our knowledge, no public datasets are available. In this paper, we define this problem as Descanning and introduce a new high-quality and large-scale dataset named DESCAN-18K. It contains 18K pairs of original and scanned images collected in the wild containing multiple complex degradations. In order to eliminate such complex degradations, we propose a new image restoration model called DescanDiffusion consisting of a color encoder that corrects the global color degradation and a conditional denoising diffusion probabilistic model (DDPM) that removes local degradations. To further improve the generalization ability of DescanDiffusion, we also design a synthetic data generation scheme by reproducing prominent degradations in scanned images. We demonstrate that our DescanDiffusion outperforms other baselines including commercial restoration products, objectively and subjectively, via comprehensive experiments and analyses.

Broadband and large-aperture metasurface edge encoders for incoherent infrared radiation.

The prevalence of computer vision systems necessitates hardware-based approaches to relieve the high computational demand of deep neural networks in resource-limited applications. One solution would be to off-load low-level image feature extraction, such as edge detection, from the digital network to the analog imaging system. To that end, this work demonstrates incoherent, broadband, low-noise optical edge detection of real-world scenes by combining the wavefront shaping of a 24-mm aperture metasurface with a refractive lens. An inverse design approach is used to optimize the metasurface for Laplacian-based edge detection across the 7.5- to 13.5-μm LWIR imaging band, allowing for facile integration with uncooled microbolometer-based LWIR imagers to encode edge information. A polarization multiplexed approach leveraging a birefringent metasurface is also demonstrated as a single-aperture implementation. This work could be applied to improve computer vision capabilities of resource-constrained systems by leveraging optical preprocessing to alleviate the computational requirements for high-accuracy image segmentation and classification.

Retrospective clinical study of hip replacement in the treatment of traumatic arthritis secondary to acetabular fracture

To investigate the clinical effect of total hip replacement (THA) in the treatment of traumatic arthritis secondary to acetabular fracture. From October 2019 to June 2022, 15 patients with secondary traumatic arthritis of acetabulum fracture were treated with THA. There were 8 males and 7 females, aged from 40 to 76 years old with an average of (59.20±9.46) years old. Prosthesis loosening, dislocation of hip joint, range of motion of hip joint, nerve injury and other conditions were recorded before and after surgery. Harris score, visual analogue scale (VAS) and imaging were used to evaluate hip joint function and surgical effect. Follow-up time ranged 6 to 39 months with an average of (18.33±9.27) months. All the 15 patients successfully completed the operation, no nerve and blood vessel injury during the operation, postoperative wound healing was stageⅠ, no infection, one case of acetabular side prosthesis loosening at half a year after operation, and recovered well after revision surgery, one case of hip dislocation was cured after open reduction treatment, no adverse consequences. Harris score at the last postoperative follow-up was (88.60±4.01) points, compared with the preoperative (47.20±11.77) points, the difference was statistically significant (P<0.05), and VAS at the lateat postoperative follow-up was 1 (1) points, compared with the preoperative 8 (2) points, the difference was statistically significant (P<0.05). At the last follow-up, the pain symptoms were relieved or disappeared, and the joint function was satisfactory. The imaging data of the latest follow-up showed joint was well pseudoradiated, no abnormal ossification occurred, and the prosthesis was not loose. THA is effective in the treatment of traumatic arthritis secondary to acetabular fracture and can effectively improve the quality of life of patients. Preoperative comprehensive evaluation and bone defect evaluation of patients, and intraoperative management of acetabulum, femur, internal fixation and bone defect are key factors for the success of surgery.

Simple stochastic model with safe speed using Exchange approach to recognizing synchronized flow as speed-synchronized phase

In order to unravel the physical and mathematical mystery of synchronized-flow mechanism and to reveal the fundamental mechanism and origin of synchronized flow produced by nonlinear stochastic processes, we have produced simple stochastic traffic flow models (the gradual-NaSch, Phoenix and mPhoenix models) with nonlinear safe speeds. In the mNaSch model and our gradual-NaSch model, the [Formula: see text]th vehicle’s speed is the same as or different from the [Formula: see text]th vehicle’s speed because they are discrete values. In the mNaSch and gradual-NaSch models, the same discrete values of the [Formula: see text]th and [Formula: see text]th states make it easy to identify synchronized flow with speed-synchronized phase of the [Formula: see text]th and [Formula: see text]th states. On the other hand, when we deal with synchronized flow in continuous traffic flow models, we face a problem. Continuous values cause the difficulty in identification of synchronization. In order to definitely clarify whether or not synchronized flow occurs in continuous models, we have established a novel idea of Exchange approach to recognizing synchronized flow as speed-synchronized phase. Our idea is generated from the analogical image that the whole system of synchronized metronomes does not change even if the [Formula: see text]th and [Formula: see text]th synchronized metronomes are exchanged. The Exchange approach (exchanging the [Formula: see text]th vehicle’s state for any [Formula: see text]th vehicle’s state in the whole system of traffic flow), which causes distortion such as a collision if non-synchronized vehicle’s states are exchanged and makes it possible to definitely clarify whether or not synchronized flow occurs in continuous models, is applied to our simple stochastic continuous model (the mPhoenix model). On the basis of the Exchange approach, we can recognize that the mPhoenix model surely reproduces synchronized flow. In addition, we have proposed mathematical approach to deriving nonlinear safe speeds which guarantee collision free driving and reproduce synchronized flow.

Auditing the inference processes of medical-image classifiers by leveraging generative AI and the expertise of physicians.

The inferences of most machine-learning models powering medical artificial intelligence are difficult to interpret. Here we report a general framework for model auditing that combines insights from medical experts with a highly expressive form of explainable artificial intelligence. Specifically, we leveraged the expertise of dermatologists for the clinical task of differentiating melanomas from melanoma 'lookalikes' on the basis of dermoscopic and clinical images of the skin, and the power of generative models to render 'counterfactual' images to understand the 'reasoning' processes of five medical-image classifiers. By altering image attributes to produce analogous images that elicit a different prediction by the classifiers, and by asking physicians to identify medically meaningful features in the images, the counterfactual images revealed that the classifiers rely both on features used by human dermatologists, such as lesional pigmentation patterns, and on undesirable features, such as background skin texture and colour balance. The framework can be applied to any specialized medical domain to make the powerful inference processes of machine-learning models medically understandable.

All-optical geometric image transformations enabled by ultrathin metasurfaces

Image processing plays a vital role in artificial visual systems, which have diverse applications in areas such as biomedical imaging and machine vision. In particular, optical analog image processing is of great interest because of its parallel processing capability and low power consumption. Here, we present ultra-compact metasurfaces performing all-optical geometric image transformations, which are essential for image processing to correct image distortions, create special image effects, and morph one image into another. We show that our metasurfaces can realize binary image transformations by modifying the spatial relationship between pixels and converting binary images from Cartesian to log-polar coordinates with unparalleled advantages for scale- and rotation-invariant image preprocessing. Furthermore, we extend our approach to grayscale image transformations and convert an image with Gaussian intensity profile into another image with flat-top intensity profile. Our technique will potentially unlock new opportunities for various applications such as target tracking and laser manufacturing.

Modeling of space debris fragment restoring technologies in the non-redundant array of aperture synthesis

The problem of monitoring space debris (SD) of anthropogenic origin is discussed to ensure the safety of near-Earth space environment exploration. For dynamic low-orbit SD fragments, acquisition and processing technologies of short-exposure image series, obtained in a non-redundant aperture synthesis array, are proposed and investigated. Specific features of the optical transfer function (OTF) of the non-redundant array, namely, its "insular" character, lead to difficulties in restoring the spatial spectrum of the control object, undistorted by the atmosphere, in the whole spatial-frequency domain of the array. It is shown that to restore the object's spatial spectrum module, undistorted by the atmosphere, in the whole spatial frequency domain of the array, it is necessary to use algorithm of the Labeyrie method, modified by the authors of the present work. To restore the phase of the spatial spectrum, it is necessary to use the algorithms of unfolding the closed phase equations of the triple correlations method. By physical modeling of the formation and registration processes of analog images in the atmosphere-array system and subsequent statistical processing of digitized images, experimental evidence is given of the effectiveness of the proposed restoring technologies to achieve high resolution of SD fragments in the array, aimed at their subsequent identification and removal. Recommendations are given for practical implementation of the considered promising construction and application technologies of optical systems to control SD fragments.

Analog image processing with nonlinear nonlocal flat optics

Digital signal processing has revolutionized many fields of science and engineering, but it still shows critical limits, mainly related to the complexity, power consumption, and limited speed of analogue-to-digital converters. A long-sought solution to overcome these hurdles is optical analog computing. In this regard, flat optics has been recently unveiled as a powerful platform to perform data processing in real-time, with low power consumption and a small footprint. So far, these explorations have been mainly limited to linear optics. Arguably, significantly more impact may be garnered from pushing this operation towards nonlinear processing of the incoming signals. In this context, we demonstrate here that nonlinear phenomena combined with engineered nonlocality in flat optics devices can be leveraged to synthesize Volterra kernels able to outperform linear optical analog image processing.