Optical Engineering + Applications最新文献

{"title":"Cataractous eye fundus image enhancement by using multi-scale tone decomposition","authors":"Oscar Ramos-Soto, Diego Oliva, J. Gómez-Correa, S. Balderas-Mata","doi":"10.1117/12.2672348","DOIUrl":"https://doi.org/10.1117/12.2672348","url":null,"abstract":"Through optical equipment such as the ophthalmoscope, it is possible to visualize and image the inner surface of the eye, where the main structures of the retina can be observed. The visual analysis of the retinal vasculature is widely used by ophthalmologists for prevention, diagnosis, and monitoring of retinal diseases. Nevertheless, derived from pathologies that generate an opacity in the crystalline lens (such as cataracts), the task of visualize blood vessels becomes difficult, since there is a lack of contrast in the fundus image. In this work, a multiscale decomposition method based on the Weighted Least Squares (WLS) optimization is applied to cataractous eye fundus images, with the aim of obtaining a better blood-vessel to background contrast. The proposed scheme is implemented over a publicly-available cataract eye fundus dataset. The experimental results provide a notorious visual improvement in contrast and restoration of blood vessels pixels and, in addition, maintains adequate saturation and lighting for visual analysis. The visual improvement of the vasculature represents a potential benefit in the ophthalmic analysis of patients with cataracts, since it is possible to observe the vascular morphology in greater detail while keeping relevant image features.","PeriodicalId":434863,"journal":{"name":"Optical Engineering + Applications","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114913101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transverse and longitudinal magnification of reconstructed images using inline digital holography with the double-sideband filter","authors":"C. Ramírez, Luisa García-Canseco, Á. Lizana","doi":"10.1117/12.2677644","DOIUrl":"https://doi.org/10.1117/12.2677644","url":null,"abstract":"Inline digital holography is useful to reconstruct focused images of microscopic objects. This configuration is less sensitive to mechanical vibrations and refraction index variations. However, the blurred conjugate image is formed over the focused image. To remove the conjugate image a double-sideband (DSB) filter was proposed. The main sketch proposed to constitute the filter is as follows: first a collimated and linearly polarized wavefront illuminates microscopic objects to be studied. A convergent lens is placed in the overlap between the diffracted wavefront and illumination wavefront. Afterwards, at the focal plane of this lens a Liquid Crystal Spatial Light Modulator (SLM-LC) is positioned, followed by a linear polarizer. Finally, the resulting fringe patterns are recorded with a CCD. Under this scenario, two phase retardation values (0° and π) are addressed to each half of the SLM-LC screen. In this form, the half of spatial frequency spectrum is blocked. Next, the values of the phase retardation on each half of SLM-LC screen are digitally exchanged, and the other half of the spatial frequency spectrum is blocked. In the computer, both fringe patterns are processed to retrieve the complex amplitude with magnitude and phase (hologram) of the diffracted wavefront, and thus, one of the conjugated images is removed. A diffraction integral equation is used to propagate digitally the hologram. Sparsity metric is applied to determine the best focused image. In this work, we provide a theoretical analysis of the longitudinal and transverse magnifications of the reconstructed images. We demonstrate that transverse and longitudinal magnification depend on the focal length of the lens as well as the length from the lens to the CCD. If the object position changes, the reconstruction length is proportional to longitudinal magnification of the system, while the transverse magnification of the reconstructed image does not vary. This is desirable for the displacement trace of moving particles, or for reconstruction of microscopic objects in different planes, in a 3D volume. Finally, we present the experimental results obtained in the reconstruction of the images of microscopic objects. We reconstruct the image of glass microspheres (diameter: 14.5 μm ± 1 μm), a micrometric reticle (100 μm), and a resolution test chart 1951 USAF, to verify longitudinal and transverse magnifications. The proposed study is useful for the study and tracking of quasi-transparent microscopic samples with optimized magnification.","PeriodicalId":434863,"journal":{"name":"Optical Engineering + Applications","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114979486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance analysis of intelligent reflecting surface aided cell-free communications","authors":"Khushnub Anwar, Imtiaz Ahmed, M. Matin, Md. Sahabul Alam, Kamrul Hasan","doi":"10.1117/12.2676589","DOIUrl":"https://doi.org/10.1117/12.2676589","url":null,"abstract":"The next generation of cellular communication networks aims to enable ubiquitous connectivity with limited inter-cell interference through cell-free massive multiple-input multiple-output (CF-MMIMO) technology. Deploying an intelligent reflecting surface (IRS) in the cell-free (CF) architecture can significantly enhance coverage area and increase network spectrum efficiency. The signals reflected from IRS can be superposed coherently at the user by introducing the phaseshift with passive reflecting elements (PREs) on IRS. Non-terrestrial communications via unmanned aerial vehicles (UAVs) are critical in providing the seamless connection of the next generation of cellular communication systems. In the current terrestrial network, the signal strength of aerial platforms like UAVs is compromised as the access points (APs) are, in general, aimed at serving ground user ends (GUEs). This challenge can be addressed by incorporating IRS into the CF-MMIMO network. In this paper, we present an IRS-assisted CF-MMIMO network architecture that provides coverage for conventional terrestrial and evolving non-terrestrial aerial user equipment (UEs) simultaneously. The terrestrial UEs experience Rayleigh fading in this architecture, while the non-terrestrial aerial UEs experience Rician fading. To assess the performance of the considered system intuitively, we derive closed-form expressions for both the downlink (DL) spectral efficiency (SE) and the overall system outage probability. These analytical tools allow us to gain valuable insights into the design of CF systems for the next generation of communication systems. To further demonstrate the effectiveness of our developed analytical framework, we validate the developed theoretical tools with Monte Carlo computer simulations for various use cases of the CF-MMIMO network.","PeriodicalId":434863,"journal":{"name":"Optical Engineering + Applications","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129626330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Breast abnormalities classification using deep learning feature extraction","authors":"Vladislav Pryadka, Andrei Krendal, J. González-Fraga, V. Kober, A. Kober","doi":"10.1117/12.2677167","DOIUrl":"https://doi.org/10.1117/12.2677167","url":null,"abstract":"In this study, the main goal is to improve the performance of existing computer diagnostic systems by proposing new processing methods. We use the public CBIS-DDSM dataset for training and validation. The dataset consists of normal screenings with benign tumors and malignant tumors, with all pathologies carefully selected and checked by a radiologist. The data set also includes ROI masks and pathology bounding boxes, as well as labels corresponding to the class of each pathology diagnosis. To achieve better results on the dataset, we transform the data for their more efficient representation using autoencoders in order to obtain features with low intraclass and high interclass variance, and apply LDA to the encoded features to classify pathologies. Methods for automated pathology detection are not considered in this article, since it is mainly focused on the classification task itself. The entire pipeline of the system consists of the following steps: first, feature extraction using pathology segmentation; dividing the data into two clusters; feature transformation using linear discriminant analysis to minimize intra-class variance; finally, the classification of pathologies. The results of this study for the classification of pathologies using various deep learning methods are presented and discussed.","PeriodicalId":434863,"journal":{"name":"Optical Engineering + Applications","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121987513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Holographic shearing interferometry and its implications for freeform characterization","authors":"Demetrious Dowdell, Isabella Feraca, Thomas Brown","doi":"10.1117/12.2675532","DOIUrl":"https://doi.org/10.1117/12.2675532","url":null,"abstract":"This work explores combining the reference sphere and nulling hologram for freeform measurements by using a nulling reflection hologram in a Fizeau geometry. To do this, we combined standard phase shifting with an iterative algorithm to solve for errors in the phase steps, obtained a phase surface, and ultimately fit it to a set of Zernike polynomials. Preliminary results show that we can characterize a surface via Zernike coefficients using in situ holographic exposures followed by a sequence of interferograms using small (<100μm) values of lateral shear.","PeriodicalId":434863,"journal":{"name":"Optical Engineering + Applications","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134132107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamic tool influence function on SiC mirror surfaces for space optical telescopes using orthogonal velocity tool","authors":"Jeong-Yeol Han, M. Bog, Ji-Woo Lee, J. Suk","doi":"10.1117/12.2677871","DOIUrl":"https://doi.org/10.1117/12.2677871","url":null,"abstract":"The quality of mirror surface is a crucial factor in enhancing the optical performance of space telescopes, and the Tool Influence Function (TIF) is an important parameter that determines the surface quality by measuring the unit removal volume. Although TIF studies have traditionally been performed under static conditions, there is a growing interest in studying dynamic TIF using a moving polishing head. In this presentation, we report on initial dynamic TIF patterns on SiC mirror surfaces for Space Optical Telescopes using the Orthogonal Velocity Tool (OVT) at KASI.","PeriodicalId":434863,"journal":{"name":"Optical Engineering + Applications","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114651886","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Low-to-mid spatial frequency wavefront error control for off-axis freeform three-mirror KASI-deep rolling imaging fast telescope","authors":"G. Lee, Yunjong Kim, Daewook Kim, Woowon Byun, Changsu Choi, Yongseok Lee, Dohoon Kim, Seunghyuk Chang, J. Ko","doi":"10.1117/12.2676309","DOIUrl":"https://doi.org/10.1117/12.2676309","url":null,"abstract":"We have developed the KASI-Deep Rolling Imaging Fast Telescope (K-DRIFT), adopting a 300 mm aperture off-axis freeform three-mirror design to detect faint and diffuse low-surface-brightness structures. By conducting the on-sky test observations and performing a series of simulations to analyze the performance of the K-DRIFT, we confirmed three main error sources causing optical performance degradation. The imaging performance of the K-DRIFT has successfully improved by correcting low-to-mid spatial frequency wavefront errors based on performance analysis results. This paper presents the K-DRIFT’s optical performance analysis algorithm and the optical performance improvement.","PeriodicalId":434863,"journal":{"name":"Optical Engineering + Applications","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126597994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Non-contact surface roughness measurement of round bars considering the effect of machining striations","authors":"Y. Igarashi, Kazunori Yamazaki","doi":"10.1117/12.2677141","DOIUrl":"https://doi.org/10.1117/12.2677141","url":null,"abstract":"By measuring scattered light, our goal is to improve the accuracy and automation of manual inspection. In this study, we attempted to measure the non-contact surface roughness of the curvature surface of a round bar sample by capturing and analyzing the scattered light distribution. We also evaluated the influence of machining marks on the round bar. A round bar workpiece (cold forged material, surface polished) was irradiated with a He-Ne laser (spot diameter Φ0.8 mm, maximum power 8 mW, wavelength 632.8 nm) and a PIN photodiode (sensor size Φ1.5 mm) was scanned to acquire the scattered light intensity distribution. The detected scattered light distribution was fitted to a scattered light distribution model based on the generalized Harvey-Shack theory to calculate surface roughness parameters. The extracted roughness parameters are root mean square roughness ”Rq” and half width of autocovariance ”lc”. The PIN photodiode was scanned in the direction of the machining striations and in the direction orthogonal to the striations, and the ratio of the lc in the two directions was used to evaluate the surface roughness anisotropy parameter ”Str”. By determining ”Str”, we can consider the effect of machining striations on machine performance. This paper presents the results of the evaluation of Str compared to the conventional method, which allows non-contact, non-destructive measurement.","PeriodicalId":434863,"journal":{"name":"Optical Engineering + Applications","volume":"350 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126029867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimizing design decision-making for remote sensing instrument specification via tolerance sensitivity analysis of Ritchey–Chrétien telescope","authors":"Sheng-Feng Lin","doi":"10.1117/12.2676010","DOIUrl":"https://doi.org/10.1117/12.2676010","url":null,"abstract":"The objective of thisstudy was to assess the tolerance sensitivity of various aperture sizes in the Ritchey–Chrétien telescope employed in remote sensing instruments. A comparative analysis was performed to identify the optimal system specification considering different aperture sizes and marginal tolerances. The results were then utilized in the Formosat– 8 satellite program to determine the most suitable aperture size for fabricating the mirror components and establish the tolerances budget for the system alignment of the Formosat–8 satellite remote sensing instrument.","PeriodicalId":434863,"journal":{"name":"Optical Engineering + Applications","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134167582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On-orbit thermal control system design and analysis for space optical telescope ROKITS","authors":"Jaegun Yoo, Jeong-Yeol Han, H. Kim, Woo-Kyoung Lee, Seonghwan Choi, Dukhang Lee, Chanhaeng Lee, Daewook Kim","doi":"10.1117/12.2676760","DOIUrl":"https://doi.org/10.1117/12.2676760","url":null,"abstract":"Space telescopes are exposed to extreme hot and cold temperature variations in the space environment depending on their orbit conditions. These temperature variations cause a significant effect on the opto-mechanical structures and lead to the final optical performance degradation. The development of space optical telescopes must achieve a thermally stable and reliable system through thermal analysis for on-orbit temperature prediction and thermal control design maintaining all components within their operating/survival temperature limits during entire mission phases. In this paper, we report the analysis results of passive and active thermal design for the ROKITS mission based on on-orbit thermal analysis taking into account the worst hot and cold conditions in the space environment using thermal analysis program - Thermal Desktop®, SINDA/FLUINT®.","PeriodicalId":434863,"journal":{"name":"Optical Engineering + Applications","volume":"226 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133367076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}