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The underground mine environment is dangerous and harsh, tracking and detecting humans based on computer vision is of great significance for mine safety monitoring, which will also greatly facilitate identification of humans using the symmetrical image features of human organs. However, existing methods have difficulty solving the problems of accurate identification of humans and background, unstable human appearance characteristics, and humans occluded or lost. For these reasons, an improved aberrance repressed correlation filter (IARCF) tracker for human tracking in underground mines based on infrared videos is proposed. Firstly, the preprocess operations of edge sharpening, contrast adjustment, and denoising are used to enhance the image features of original videos. Secondly, the response map characteristics of peak shape and peak to side lobe ratio (PSLR) are analyzed to identify abnormal human locations in each frame, and the method of calculating the image similarity by generating virtual tracking boxes is used to accurately relocate the human. Finally, using the value of PSLR and the highest peak point of the response map, the appearance model is adaptively updated to further improve the robustness of the tracker. Experimental results show that the average precision and success rate of the IARCF tracker in the five underground scenarios reach 0.8985 and 0.7183, respectively, and the improvement of human tracking in difficult scenes is excellent. The IARCF tracker can effectively track underground human targets, especially occluded humans in complex scenes.

Purpose Dosimetry of ionizing radiation in the presence of strong magnetic fields is gaining increased relevance in light of advances for MRI‐guided radiation therapy. While the impact of strong magnetic fields on the overall response of ionization chambers has been simulated and measured before, this work investigates the local impact of the magnetic field on dose response in an ion chamber. High‐resolution 1D and 2D response maps have been created for two small clinical thimble ionization chambers, the PinPoint chambers 31006 and 31014 (Physikalisch Technische Werkstaetten Freiburg, Germany). Methods Working on the Imaging and Medical Beam Line of the Australian Synchrotron an intense kilovoltage radiation beam with very low divergence, collimated to 0.1 mm was used to scan the chambers by moving them on a 2D motion platform. Measured current and beam position were correlated to create the response maps. Small neodymium magnets were used to create a field of about 0.25 T. Chamber axis, magnetic field, and beam direction were perpendicular to each other. Measurements were performed with both orientations of the magnetic field as well as without it. Chamber biases of 5 and 250 V in both polarities were used. Results The local distribution of the response of small thimble‐type ionization chambers was found to be impacted by a magnetic field. Depending on the orientation of the magnetic field, the chamber response near the stem was either enhanced or reduced with the response near the tip behaving the opposite way. Local changes were in the order of up to 40% compared to measurements without the magnetic field present. Bending of the central electrode was observed for the chamber with the steel electrode. The size of the volume of reduced collection near the guard electrode was impacted by the magnetic field. As the here investigated beam and field parameters differ from those of clinical systems, quantitatively different results would be expected for the latter. However, the gyroradii encountered here were similar to those of a 6–7 MV MRI linac with a 1.5 T magnet. Conclusions Magnetic fields impact the performance of ionization chambers also on a local level. For practical measurements this might mean a change in the effective point of measurement, in addition to any global corrections. Further knowledge about the local response will help in selecting or constructing optimized chambers for use in magnetic fields.

Background: The Integral Quality Monitor (IQM®) is an independent online dosimetry device attached to the treatment machine to monitor the accuracy of radiation delivery. Objective: This study investigates the influence of beam segment size and displacement as projected onto the IQM chamber on the signals and determine how individual signals can be added to get a combined segment signal made up of smaller segments.Material and Methods: This is an experimental original research type of study. IQM response maps were generated by irradiating the IQM sensitive area with small elementary segments and measuring their corresponding signals per monitor unit (MU). The output signal/MU was measured for regular and irregular fields and compared with the predicted signal/MU obtained from decomposing the open segment into a set of smaller regular segments and summing their signals from their respective response maps. The dependence of signals on segment size, shape, location and combination was investigated. Results: Predicted signals were calculated within 95-98 % accuracy for regular fields and 90-98% for irregular fields. More uniform fluence contain distribution for larger segments was observed. Response maps were consistent with the geometrical symmetry in the chamber’s wedge shape and the symmetry in the linac fluence. Conclusion: The field decomposition method allows the pre-calculation of known segment output signals per MU within 2% error, although the accuracy drops significantly for smaller, irregular fields. A method of correcting predicted signals in smaller segments needs to be laid down to get a better match with measured signals.

Nowadays, visual object tracking becomes a hotspot and difficulty to achieve a real-time and accurate target tracking, but the Siamese network has solved these difficulties because of its good tracking effect and real-time performance. The location of the target in the previous frame is the template, and the similarity matching is carried out in the search area of the current frame. However, it uses Alexnet network with simple structure and fewer layers to extract features, and just uses a score map to predict the final position of the object. Aiming at these problems, in this paper, we propose the Siamese network of fused response map that use the Alexnet network with fine tuning to extract target features, and weight fusion of score maps to estimate the final position of object. Sufficient experiments on the VOT2015 and OTB100 benchmarks validate that our tracker can improve tracking performance, and perform at 60FPS.

Att maximera sjukhusens och räddningstjänstens täckning av befolkningen är en viktig säkerhetsfråga som diskuteras inom bland annat hälsovårdsplaneringen. Geografiska informationssystem (GIS) kan användas som ett hjälpmedel för att analysera och presentera andelen befolkning som är utanför sjukvårdens täckningsområden och även visa variationer på täckningsområdena när anläggningar slås ihop eller läggs ned. Syftet med arbetet är att presentera en ny, vektorbaserad nätverksanalys i GIS-miljö för att undersöka hur täckningsområdena för räddningstjänsten i Uppsala kommun påverkas. För att utföra nätverksanalysen användes data från Nationella Vägdatabasen (NVDB) över Uppsala kommun. Attributen som användes från NVDB innehöll information om framförallt hastighetsbegränsningar, väghierarki, tid, restriktioner och gatunamn. Täckningsområdena beräknades med ArcGIS och tilläggsprogrammet Network Analyst och resulterade i en översiktlig karta med räddningstjänstens insatstider och även enskilda insatskartor. Jämfört med tidigare resultat av insatskartor för samma områden, gav nätverksanalysen mer noggranna resultat med utökade täckningsområden för varje räddningstjänststation. Antalet täckta tätorter ökades och även andelen tätortsbefolkning. Metoden som beskrivs är användbar för att beräkna geografiska täckningsområden och andelen population som tjänas inom en specifik tid. Det är ett särskilt viktigt verktyg som kan nyttjas av politiker vid till exempel beslutsfattande. Maximizing the catchment areas of emergency services is an important safety question that is discussed in health planning. Geographic Information Systems (GIS) can be used as a support to analyse and present the percentage of the population that is outside the hospital catchment area and also show catchment area variations by restructuring the organization. The aim of this thesis is to present a new, vector-based network analysis and to investigate how the catchment areas for the emergency service in Uppsala municipality will be affected. To perform the network analysis, data over Uppsala municipality was used from Nationella Vägdatabasen (NVDB). The attributes that were used contained information about speed limits, road hierarchy, restrictions, time and road names. ArcGIS and the extension Network Analyst were used to calculate the catchment areas. The results obtained from the analysis were shown in a regional chart and individual maps with the emergency service drive time for each station. In comparison with previous results, the network analysis presents more accurate catchment areas. The method described is very useful when calculating geographic catchment areas and the percentage of the population that is served within a certain time. It is an important tool that can be used by politicians within decision making.

Porphyrins consist of twenty-atom rings containing four nitrogen atoms and can be used as sensor to detect odours and gases. This thesis investigates whether or not porphyrins can be used as functional materials on grid gate devices. Drops of PVC embedded porphyrins were deposited on the surface of a grid gate which is a Metal Oxide Semiconductor (MOS) capacitor. In order to detect the gas sensing properties of the porphyrins a light addressable method called Scanning Light Pulse Technique (SLPT) has been used. Drops of porphyrins were deposited with a stretched capillary tube (1 mm diameter). The MOS capacitor has been exposed to nitrogen atmosphere as reference environment, while the target gases were carbon monoxide (100 ppm) and ammonia (500 ppm). The result from the eight porphyrins is that one of them [Pt(II) TPP] has a response for both gases, ammonia induces a change in both the work function and surface resistance, while the carbon monoxide induces only a change in the surface resistance.