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Achieving high-resolution thermal imagery in low-contrast lake surface waters by aerial remote sensing and image registration
摘要： A two-platform measurement system for realizing airborne thermography of the Lake Surface Water Temperature (LSWT) with ~0.8 m pixel resolution (sub-pixel satellite scale) is presented. It consists of a tethered Balloon Launched Imaging and Monitoring Platform (BLIMP) that records LSWT images and an autonomously operating catamaran (called ZiviCat) that measures in situ surface/near surface temperatures within the image area, thus permitting simultaneous ground-truthing of the BLIMP data. The BLIMP was equipped with an uncooled InfraRed (IR) camera. The ZiviCat was designed to measure along predefined trajectories on a lake. Since LSWT spatial variability in each image is expected to be low, a poor estimation of the common spatial and temporal noise of the IR camera (nonuniformity and shutter-based drift, respectively) leads to errors in the thermal maps obtained. Nonuniformity was corrected by applying a pixelwise two-point linear correction method based on laboratory experiments. A Probability Density Function (PDF) matching in regions of overlap between sequential images was used for the drift correction. A feature matching-based algorithm, combining blob and region detectors, was implemented to create composite thermal images, and a mean value of the overlapped images at each location was considered as a representative value of that pixel in the final map. The results indicate that a high overlapping field of view (~95%) is essential for image fusion and noise reduction over such low-contrast scenes. The in situ temperatures measured by the ZiviCat were then used for the radiometric calibration. This resulted in the generation of LSWT maps at sub-pixel satellite scale resolution that revealed spatial LSWT variability, organized in narrow streaks hundreds of meters long and coherent patches of different size, with unprecedented detail.
关键词： Lake surface water temperature,Uncooled infrared camera,Image registration,Lake Geneva,Thermal imagery,Aerial remote sensing
更新于2025-09-23 15:23:52
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Automatic calibration of an arbitrarily-set near-infrared camera for patient surface respiratory monitoring
摘要： Purpose: A patient’s respiratory monitoring is one of the key techniques in radiotherapy for a moving target. Generally, such monitoring systems are permanently set to a fixed geometry during the installation. This study aims to enable a temporary setup of such a monitoring system by developing a fast method to automatically calibrate the geometrical position by a quick measurement of calibration markers. Methods: One calibration marker was placed on the isocenter and the other six markers were placed at positions 5-cm apart from the isocenter to the left, right, anterior, posterior, superior, and inferior directions. A near-infrared (NIR) camera (NIC) (Kinect v2 (Microsoft Corp.)) was arbitrarily set with ten different angles around the calibration phantom with a fixed tilting-down angle at approximately 45° in a linear accelerator treatment vault. The 3D coordinates in the camera (Cam) coordinate system (CS) (x and y are the horizontal and vertical coordinates of the image, respectively, and z is a coordinate along the NIR time-of-flight) were taken for one minute with 30 frames per second. The data corresponding to the measurement times of 1, 3, 10, 30, and 60 s were created to mimic various measurement times. These data were used to calculate the initial matrix elements, which included six parameters of the pitching, yawing, and rolling angles; horizontal 2D translation in the treatment room; and the source-to-axis distance of NIC, for a conversion from the Cam CS to the treatment-room CS for which the origin was defined at the isocenter (Iso coordinate). The six parameters were then optimized to minimize the displacements of the calculated marker coordinates from the actual positions in the Iso CS. The 3D positional accuracy and angular accuracy of the conversion were evaluated. The random error of the Iso coordinates was analyzed through a relation with the angle of each measurement setup. Results: Three angles of NIC and relative translation vectors were successfully calculated from the measurement data of the calibration markers. The achieved spatial and angular accuracies were 0.02 mm and 1.6°, respectively, after the optimization. Among the mimicked measurement times investigated in this study, both spatial and angular accuracies had no dependence on the measurement time. The average random error of a static marker was 0.46 mm after the optimization. Conclusion: We developed an automatic method to calibrate the 3D patient surface monitoring system. The procedure developed in this study enabled a quick calibration of NIC, which can be easily repeated multiple times for a frequent and quick setup of the monitoring system.
关键词： near-infrared camera,respiratory monitoring,calibration
更新于2025-09-23 15:22:29
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The contribution to the modal analysis using an infrared camera
摘要： The paper deals with modal analysis using an infrared camera. The test objects were excited by the modal exciter with narrowband noise and the response was registered as a frame sequence by the high speed infrared camera FLIR SC7500. The resonant frequencies and the modal shapes were determined from the infrared spectrum recordings. Lock-in technology has also been used. The experimental results were compared with calculated natural frequencies and modal shapes.
关键词： resonance,infrared camera,modal analysis,vibration,modal shape
更新于2025-09-23 15:21:01
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Fatigue limit estimation using IR camera
摘要： Determination of fatigue limit by traditional method is associated with testing of large number of specimens. This is caused by more scatter in test results and therefore a higher amount of tests are needed to generate a statistically reliable trend. The paper presents rapid and reliable estimation of fatigue limit using infrared thermography. By analysing the temperature of the material surface during cyclic loading it is possible to evaluate the dynamic behaviour of a structure and determine the fatigue limit. The method provides reliable results using a very little number of specimens in a very short time compared with traditional method.
关键词： thermography,W?hler diagram,infrared camera,Fatigue limit
更新于2025-09-23 15:21:01
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Separation Between Coal and Gangue Based on Infrared Radiation and Visual Extraction of the YCbCr Color Space
摘要： Distinguishing between coal and gangue in the production lines of mining factories based on the thermal energy and infrared radiation emission of an object is feasible. In this paper, we use an infrared camera (IC) to distinguish between coal and gangue in the industrial mining field. Additionally, this system is considered to be a binary classification system that has two classes. We analyze the infrared images of coal and gangue; then extract the appropriate texture features from the infrared images in order to develop an accurate classification system by using support vector machine (SVM). The method applied in this work essentially depends on feature extraction of images. The statistical features based on gray level information (GLI), grey-level cooccurrence matrix (GLCM) and visual features are executed. Thus, we suggest preparation steps to obtain one select feature before importing the data into the SVM classifier, and this approach is adopted as the fundamental basis for our work. We exploit only one feature of the infrared image, namely, Cb, which is extracted from the YCbCr color space, and then compute the mean value of Cb after heating and capturing the photos for the coal and gangue samples. The proposed method achieves a high classification accuracy 97.83 % by using Gaussian-SVM.
关键词： YCbCr,SVM,emissive power,gangue recognition,infrared camera application,Industrial mining
更新于2025-09-19 17:13:59
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[ACM Press the 2nd International Conference - Sydney, NSW, Australia (2018.10.06-2018.10.08)] Proceedings of the 2nd International Conference on Graphics and Signal Processing - ICGSP'18 - Development of Communication Aid Device for Disabled Persons Using Corneal Surface Reflection Image
摘要： Improving quality of life (QOL) has become an important issue for patients with neurological diseases such as ALS (amyotrophic lateral sclerosis) and SMA (spinal atrophy). At the same time, it is indispensable to secure a communication device that displays its own intention, and various interfaces have been proposed. In this research, we developed a glasses-type switching wearable device focusing on eyeball movement. Here, images around the eyeball were obtained by USB-camera equipped with infrared LEDs, and pupils were extracted by Hough transform procedure. Furthermore, in order to apply a communication aid operation, a detection model of the line-of-sight direction was constructed by acquiring the coordinates of the cornea surface reflection image.
关键词： Image processing,Infrared camera,Eye movement,Non-contact switch
更新于2025-09-16 10:30:52
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Single track scanning experiment in laser powder bed fusion process
摘要： Laser powder bed fusion (LPBF) process utilizes laser source to melt the powder particles. As a result, melt pool is formed which develops along the scan track. In this study, single track scanning with Ti-6Al-4V alloy is performed in alternate layers over the supporting base pad. Multiple single scan tracks with scanning speeds of 200mm/s, 400 mm/s and 600 mm/s are defined and thermal responses are captured using infrared camera. The thermal images record the apparent temperature measurements; therefore, derivate method is used to find the liquidus-solidus transition region which is required to estimate the melt pool length and width. Based on the estimation, the average melt pool width of the single track decreased with increasing speed while the average melt pool length for 200 mm/s scanning speed was 438.62 μm, for 400 mm/s was 432.27 μm and for 600 mm/s was 451.2 μm. Besides, cylindrical powder container samples with enclosed single tracks were designed to investigate internal features using computed tomography (CT). The CT images showed that the scanning speed of 200 mm/s and 400 mm/s resulted in formation of significant number of pores due to keyhole formation which may contribute to variation in melt pool length.
关键词： Thermal image,Single track,Infrared Camera,Porosity,Melt pool
更新于2025-09-12 10:27:22
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Fields of application for laser beam polishing of optical glasses
摘要： Conventional manufacturing of freeform optics is expensive and elaborate. The laser beam as a polishing tool offers the possibility to produce optical surfaces fast and effective. The aim of new research on laser beam polishing of optical glasses is to achieve a polished surface finish irrespective of the surface geometrics. The carbon dioxide laser is applied to process pre-machined specimen with different roughness’s. During the polishing process an infrared camera is necessary to monitor the temperature on the surface. An annealing process reduces the process-related tensions. In addition, the cleaning process is investigated to minimize the surface damages. To characterize the surface topographic a white-light interferometer and a stylus instrument are applied. Laser beam polishing of minerals glasses such as N-BK7?, BF33? and fused silica enables surface roughness of less than Ra < 5 nm by form maintenance. By means of self-design setup, the adaption of laser beam polishing on glass cylinders, lenses or freeform is possible. As a result a parallel laser beam with a diameter of 12.65 mm is applied to process tilted surfaces up to 45°. With a laser parameter modulation, the angle-dependent absorption depending on the intensity of the laser radiation is considered.
关键词： white-light interferometer,surface finish,optical glasses,annealing process,cleaning process,infrared camera,carbon dioxide laser,laser beam polishing,stylus instrument
更新于2025-09-11 14:15:04
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Thermometry of photosensitive and optically induced electrokinetics chips
摘要： Optically induced electrokinetics (OEK)-based technologies, which integrate the high-resolution dynamic addressability of optical tweezers and the high-throughput capability of electrokinetic forces, have been widely used to manipulate, assemble, and separate biological and non-biological entities in parallel on scales ranging from micrometers to nanometers. However, simultaneously introducing optical and electrical energy into an OEK chip may induce a problematic temperature increase, which poses the potential risk of exceeding physiological conditions and thus inducing variations in cell behavior or activity or even irreversible cell damage during bio-manipulation. Here, we systematically measure the temperature distribution and changes in an OEK chip arising from the projected images and applied alternating current (AC) voltage using an infrared camera. We have found that the average temperature of a projected area is influenced by the light color, total illumination area, ratio of lighted regions to the total controlled areas, and amplitude of the AC voltage. As an example, optically induced thermocapillary flow is triggered by the light image-induced temperature gradient on a photosensitive substrate to realize fluidic hydrogel patterning. Our studies show that the projected light pattern needs to be properly designed to satisfy specific application requirements, especially for applications related to cell manipulation and assembly.
关键词： Thermocapillary flow,Optically induced electrokinetics,Infrared camera,Hydrogel patterning,Temperature distribution,OEK chip
更新于2025-09-10 09:29:36
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[IEEE 2018 IEEE XXVII International Scientific Conference Electronics (ET) - Sozopol, Bulgaria (2018.9.13-2018.9.15)] 2018 IEEE XXVII International Scientific Conference Electronics - ET - Implementation of Internet of Things based solutionof wireless infrared camera with MLX90621 sensor
摘要： In this paper a low-cost solution applicable in the field of continuous monitoring of critical equipment in industry and smart homes is described. It employs a relatively new IR array sensor MLX90621 and implements the IoT concept and three-layer architecture. The implementation of this IoT solution is based on an open source hardware microcontroller development board PIC32-T795 and wireless MOD Wi-Fi ESP8266 module. It is considered to be with reasonable cost and affordable for the potential users. The paper demonstrates the benefits of having an inexpensive infrared sensor as a part of the developed solution for continuous monitoring of critical equipment for overheating.
关键词： Internet of Things,Three layers architecture,Wireless Infrared Camera,IR array sensor
更新于2025-09-09 09:28:46