Infrared Remote Sensing and Instrumentation XXXI最新文献

{"title":"System for continuous evaluation of optical path asymmetry","authors":"M. Špaček, J. Vojtěch, J. Roztocil","doi":"10.1117/12.2678936","DOIUrl":"https://doi.org/10.1117/12.2678936","url":null,"abstract":"Precise time and stable radio frequency dissemination is becoming standard application in optical networks. The White Rabbit system is commonly used for this purpose to support applications that require precise time and a stable frequency signal. Optical fibers are preferred for distributing the precise time and frequency signal in this system. To achieve best results, i.e. determine absolute offsets, it is necessary to know the asymmetry of the optical transmission path in which the system is deployed. We developed a device based on a MEMS optical switch that measures the delay of the optical path in both the forward and reverse directions. These measurements are used to continuously evaluate changes in the asymmetry of the transmission path, and the resulting asymmetry can be used to calibrate the time transfer system.","PeriodicalId":217084,"journal":{"name":"Infrared Remote Sensing and Instrumentation XXXI","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129005512","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":"Optical centroidal efficiency and energy on rectangular pixel","authors":"M. Strojnik, Yaujen W. Wang","doi":"10.1117/12.2680219","DOIUrl":"https://doi.org/10.1117/12.2680219","url":null,"abstract":"High performance megapixel focal plane arrays with small pixels have been widely used in modern optical remote sensing, astronomical, and surveillance instruments. In the prediction models applied in the traditional instrument performance analysis, the image of a point source is assumed to fall on the center of a detector pixel. A geometrical image of a point source in the realistic optical system may actually fall on any position on the detector pixel because the sensor’s line-of-sight includes pointing errors and jitter. This traditional assumption may lead to an optimistic error, estimated at between 10% and 20%. We present the critical factors that impact the performance estimate in a realistic instrument design based on the prediction for the noise equivalent power (NEP). They are the optical centroid efficiency (OCE) and the ensquared energy, or more precisely, the energy on the rectangular detector pixel (EOD).","PeriodicalId":217084,"journal":{"name":"Infrared Remote Sensing and Instrumentation XXXI","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133005441","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":"Finite element analysis of a thickness meter based on laser shock waves","authors":"J. R. González Romero, Roberto Carlos Barragán Campos, G. Gómez-Rosas, G. Garcia-Torales, M. Strojnik","doi":"10.1117/12.2677947","DOIUrl":"https://doi.org/10.1117/12.2677947","url":null,"abstract":"A laser shock wave is a pressure wave that travels through a material at supersonic speed induced by a high-power laser pulse. Shock waves suddenly change direction as reflected at the physical limits of the medium, producing interference between the wave remnants. The reflected wave reaches the front surface transiting a distance as a function of the thickness and the reflection angle. The time it takes for the shock wave from being induced to reflect toward the front surface of the material can be used to determine the thickness of the propagation medium. A finite element method estimate the propagation of a laser shock wave in four basic geometric shapes of 6061-T6 aluminum alloy. The time it takes to reach the front surface of the geometric shapes is measured. Its controlled the material thickness and spatial coordinate of the induction. The effects of the porosity, absorption and transmission of the medium are ignored. The results demonstrate the feasibility of use the time-of flight as a thickness measurement and a distribution of compression and pressure zones inside the medium generated by the wave interference. Some applications of this method are to determine the thickness of solid materials, the estimation of caverns or aquifers on geophysics, and the determination of the density of a material.","PeriodicalId":217084,"journal":{"name":"Infrared Remote Sensing and Instrumentation XXXI","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132534654","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":"Single spectral band of health vegetation detection using a conventional camera","authors":"Roberto Carlos Barragán Campos, G. Garcia-Torales, J. R. González Romero, M. Strojnik","doi":"10.1117/12.2677925","DOIUrl":"https://doi.org/10.1117/12.2677925","url":null,"abstract":"Remote sensing used in vegetation monitoring has been a significant study area for decades. With the advent of multispectral and hyperspectral cameras, detecting healthy vegetation in forests and crops were more accessible through the ratio of different spectral bands that resulted in other vegetation indices. However, even with the usefulness and practicality of these methods, they need to be more accurate since they are relative values that depend on several factors of the internal composition of the vegetation. This work proposes the analysis of a spectral bandwidth of a central wavelength of 1 μm, using a conventional CCD camera as a detector with a bandpass filter with a linewidth of 10 nm. This range presents characteristics of water absorption but also reflectance due to the cellulose of the cell walls of the leaves. In this way, using the electro-optical array, the radiation reflected changes by several leaves will be analyzed considering the hydration and deterioration of the leaf.","PeriodicalId":217084,"journal":{"name":"Infrared Remote Sensing and Instrumentation XXXI","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124853687","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":"Technology research of 1 km quantum lidar system","authors":"S. Bi","doi":"10.1117/12.2676630","DOIUrl":"https://doi.org/10.1117/12.2676630","url":null,"abstract":"Lidar (laser radar) offers advantages over conventional radar in terms of higher resolution, greater anti-interference capability and ultra-low altitude detection performance. However, Lidar has now reached a bottleneck in terms of detection range and is no longer able to correctly identify targets beyond 500 meters, thus failing to meet the requirements for detection, measurement and imaging. To break this bottleneck, we have developed a Quantum Lidar with a detection range of up to one kilometre, which is based on a quantum vacuum squeezed laser and can compress the photon fluctuation by 5.6dB in the vacuum state through quasi-phase matching in non-linear crystals, reducing the quantum noise of laser which accounts for 73% of the lidar, thus reducing the overall noise of the quantum lidar by 3.27dB and improves the phase stability of the laser (from 10 minutes to more than 120 minutes) to achieve higher accuracy measurements, with a Signal-Noise Ratio (SNR) twice that of conventional lidar, and therefore a sensitivity twice as high. The basic technical implementation is to use a 20W power 1064nm wavelength continuous wave laser (CW, M2 less than or equal to 1.05) to irradiate a target located one kilometre away. By detecting a very weak reflected laser (power=10μW ± 5μW) which is exponentially attenuated by distance, We use noiseless amplification by a quantum vacuum-squeezed laser with the same power magnitude to obtain a higher power (7dB amplification) and higher signal-noise ratio (4.77dB SNR improvement). A reflective lens set (250mm aperture) of our design is used to receive the laser diffusion due to the 4mrad transmission angle of one kilometre. In the squeezed laser system, the resonant cavity locking efficiency is improved to 99.7%, and the re-locking time is less than 0.3s, it is directly switchable with the balance homodyne detection system. The mode cleaner improves the transverse mode quality(the mode bandwidth is reduced by 67%) while filtering high-frequency noise. The quantum lidar imaging system has been developed, and the experimental results show that the resolution of the laboratory-simulated long-range decay experiment is 3 times higher than that of traditional lidar is a promising development. This means that the system can detect and image smaller objects and features with greater accuracy and precision. The use of a self-developed quantum enhancement algorithm to obtain a 5 times higher contrast lidar image is also a significant improvement, and the use of a quantum denoising algorithm to reduce graphic distortion and image scatter caused by atmospheric pollution and environmental interference is a critical development. These issues can significantly degrade the quality of lidar images, so being able to mitigate their effects is a significant step forward. Through a self-developed LiDAR 3D reconstruction algorithm, the reconstruction efficiency is increased by 3 times and the resolution is increased by 2.5 times, which ","PeriodicalId":217084,"journal":{"name":"Infrared Remote Sensing and Instrumentation XXXI","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132931749","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":"Three-mirror optical system designs using y-y-bar diagram","authors":"M. Strojnik, Yaujen W. Wang","doi":"10.1117/12.2678374","DOIUrl":"https://doi.org/10.1117/12.2678374","url":null,"abstract":"The off-axis three-mirror optical system is derived from the classical Cooke triplet or a derivative of the inverse telephoto lens. By properly arranging an internal reimaging mechanism or altering the location of the optical stop, one can create different versions of three-mirror optical systems. They include very compact configurations and wide field of view imagers. Insights into the optical design process, manufacturing, stray light management, and remote sensing applications are presented.","PeriodicalId":217084,"journal":{"name":"Infrared Remote Sensing and Instrumentation XXXI","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124620584","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":"Thermal detection of thyroid pathologies using artificial neural networks","authors":"J. F. Flores Nuñez, Miguel Angel Jurado-Aguirre, Alfredo Pérez-Nájera, Adán Cruz, Francisco J. Gonzalez","doi":"10.1117/12.2682055","DOIUrl":"https://doi.org/10.1117/12.2682055","url":null,"abstract":"Thyroid cancer is the most common type of neoplasm in the head and neck regions, thermal imaging has been used successfully for medical diagnostic purposes in areas such as breast cancer, wound care, vascular diseases, skin cancer and eye diseases. The thyroid is a richly vascularized gland that is located close to the skin, its hyper or hypo activity modifies the temperature pattern of the neck making thermography a good candidate to evaluate possible pathologies by digital infrared thermography. In this work an Artificial Neural Network based on the Nested U-Net architecture is trained and used to detect thyroid pathologies. Two thermographic databases were used to train the artificial neural network, the dataset was split into 80% for training and 20% for testing, with cross-validation used to evaluate the network's performance. The error between the predicted masks and the actual masks is calculated with the combination of Binary Cross Entropy (BCE) Loss and Dice Loss using Adam algorithm as training rule, with a cosine annealing schedule during 1500 epochs with a learning rate of 0.003 and a batch size of 6. Results show that when calculating the correlation coefficient between these deltas and the results of thyroid ultrasound expressed in the ACR TI-RADS classification, a high degree of correlation is obtained.","PeriodicalId":217084,"journal":{"name":"Infrared Remote Sensing and Instrumentation XXXI","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117237202","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}