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Abstract A panorama ensures a stunning wide-angle field of view up to 360° representation of a scene, exceeding the limits of a normal photograph. Panoramic cameras satisfy the single-viewpoint characteristic. There are several types of panoramic cameras for 360-degree imaging. Multi-camera panoramic imaging systems pose a difficulty in obtaining a single projection center for the cameras. In a variety of practical implementations of panoramic cameras, it is possible to calculate three-dimensional coordinates from a panoramic image, especially using the Direct Linear Transformation (DLT) method. In this study, not only a defining method of the non-uniform image coordinate system is presented by utilizing the C-Means algorithm for a single panoramic image, captured with a Ladybug2 panoramic camera in a panoramic calibration room but also the use of an elliptical panoramic projection coordinate system is defined by the Singular Value Decomposition method in a panoramic view. The results of the suggested method have been compared with the DLT algorithm for a single panoramic image which defined a conventional photogrammetric image coordinate system. It has been observed that the proposed method provides more accurate results for the 3D coordinate definition.

Purpose: Surgical extraction of third molars can be challenging due to several factors, including increased bone density, which causes the bone structures to lose their elastic properties. The purpose of this study is to compare the trabecular structure surrounding the impacted mandibular third molar (M3M) with the normal alveolar trabecular pattern using the fractal analysis method. Materials and Methods: A total of 47 dental panoramic radiographs (DPRs) of the patients were included in the study. The region of interest (ROI) was defined as the area between the distal root of the second molar and the mesial root of the third molar tooth (ROI1) and between the distal root of the first molar tooth and the mesial root of the second molar tooth (ROI2). Bone tissue was analyzed by FD analysis. Regions other than the area measured with FD were also evaluated using BMFD to assess the bone marrow. Fractal dimension (FD) and bone marrow fractal dimension (BMFD) analyses were performed on the selected ROIs using the ImageJ software. Results: The mean FD values of 47 patients were found to be 1.135 for ROI1 and 1.105 for ROI2, respectively. The mean BMFD values were found to be 1.591 for ROI1 and 1.587 for ROI2. The results of the FD analysis (p = 0.078) and BMFD analysis (p = 0.731) showed no significant difference between ROI1 and ROI2. Conclusions: It is crucial to evaluate the trabecular structure prior to surgery of the impacted M3Ms. Bone density surrounding the impacted M3Ms appears to be higher than that of healthy alveolar bone. Furthermore, the fact that males have denser bones than females should be considered in surgical procedures. The FD analysis method may be useful in evaluating the trabecular structure of impacted M3Ms. [ABSTRACT FROM AUTHOR]

A panorama ensures a stunning wide-angle field of view up to 360° representation of a scene, exceeding the limits of a normal photograph. Panoramic cameras satisfy the single-viewpoint characteristic. There are several types of panoramic cameras for 360-degree imaging. Multi-camera panoramic imaging systems pose a difficulty in obtaining a single projection center for the cameras. In a variety of practical implementations of panoramic cameras, it is possible to calculate three-dimensional coordinates from a panoramic image, especially using the Direct Linear Transformation (DLT) method. In this study, not only a defining method of the non-uniform image coordinate system is presented by utilizing the C-Means algorithm for a single panoramic image, captured with a Ladybug2 panoramic camera in a panoramic calibration room but also the use of an elliptical panoramic projection coordinate system is defined by the Singular Value Decomposition method in a panoramic view. The results of the suggested method have been compared with the DLT algorithm for a single panoramic image which defined a conventional photogrammetric image coordinate system. It has been observed that the proposed method provides more accurate results for the 3D coordinate definition. [ABSTRACT FROM AUTHOR]

Vehicle-borne mobile mapping systems (MMSs) have been proven as an efficient means of photogrammetry and remote sensing, as they simultaneously acquire panoramic images, point clouds, and positional information along the collection route from a ground-based perspective. Obtaining accurate matching results between point clouds and images is a key issue in data application from vehicle-borne MMSs. Traditional matching methods, such as point cloud projection, depth map generation, and point cloud coloring, are significantly affected by the processing methods of point clouds and matching logic. In this study, we propose a method for generating matching relationships based on panoramic images, utilizing the raw point cloud map, a series of trajectory points, and the corresponding panoramic images acquired using a vehicle-borne MMS as input data. Through a point-cloud-processing workflow, irrelevant points in the point cloud map are removed, and the point cloud scenes corresponding to the trajectory points are extracted. A collinear model based on spherical projection is employed during the matching process to project the point cloud scenes to the panoramic images. An algorithm for vectorial angle selection is also designed to address filtering out the occluded point cloud projections during the matching process, generating a series of matching results between point clouds and panoramic images corresponding to the trajectory points. Experimental verification indicates that the method generates matching results with an average pixel error of approximately 2.82 pixels, and an average positional error of approximately 4 cm, thus demonstrating efficient processing. This method is suitable for the data fusion of panoramic images and point clouds acquired using vehicle-borne MMSs in road scenes, provides support for various algorithms based on visual features, and has promising applications in fields such as navigation, positioning, surveying, and mapping. [ABSTRACT FROM AUTHOR]

Unlike imaging in air, underwater panoramic imaging faces great challenges arising from water pressure and diminished light, necessitating special lens packaging and focused underwater illumination. The processing of underwater images from multiple channels necessitates adaptations to existing image processing algorithms to mitigate color cast, noisy points, and other imaging defects. And based on the hot research of panoramic video transmission, the underwater panoramic imaging system on the ROV platform holds great development potential.Based on the technical research of underwater panoramic photography, this paper first elaborates on the generation and transmission of underwater panoramic images and discusses two camera layouts: distributed and integrated, utilizing the remotely operated vehicle (ROV) platform as the carrier, through an analysis of camera hardware requirements. Subsequently, it introduces the creation of panoramic images from multiple channels of image data through a process involving image preprocessing, stitching, and fusion. Lastly, taking into account of remote video transmission through water boundaries, a self-adaptive multi-rate transmission scheme is presented, based on the stream division into slices (Tile stream) for panoramic videos. From the development of underwater panoramic technology, with the improvement of panoramic technologies such as lossless image stitching, iterative computing speed of image processors, image restoration, ultra bandwidth connection, and panoramic video transmission, ROV platform panoramic camera systems will be widely applied.

Ground testing results are presented for the landing platform television system (TSPP) within the complex of scientific payloads onboard the ExoMars-2022 spacecraft. In the course of the ground testing, the different operation modes have been checked and the camera characteristics have been measured and calibrated. The Space Research Institute (IKI RAS) has obtained photographic material from each camera, with the cameras being installed on a stand that simulates in full scale the ExoMars-2022 landing platform. In addition, special measurements have been collected for the cameras' most important characteristics: horizontal and vertical angular field of view, distortion, focal length, resolution, dynamic range, vignetting coefficient, and absolute sensitivity. [ABSTRACT FROM AUTHOR]

Background and purpose: Early diagnosis of jaw lesions is of great importance, especially in children. The aim of the present study was to investigate the frequency of jaw lesions in panoramic radiography of children (5-12 years old) in north of Iran. Materials and methods: In this study, 1000 panoramic images of children attending oral radiology centers (2012-2019) in north of Iran were studied during one year. Information, including the age, gender, and presence or absence of any jaw lesion were extracted from the radiographic images of patients. Data analysis was carried out in SPSS V22 applying Chi-square. Results: Out of 1000 panoramic images, 188 (18.8%) were found with jaw lesions. The mean age of children with these lesions was 8.64±2 years. Radiolucent lesions (in 185 images) were more frequent than radiopaque lesions. Conclusion: Radiolucent lesions were more of periapical lesions.

The daily image quality assessment involves large datasets that consume a lot of time and effort. This study aims to evaluate a proposed automated calculator for image distortion analysis in 2-dimensional (2D) panoramic imaging mode for a dental cone beam computed tomography (CBCT) system in comparison with present manual calculations. A ball phantom was scanned using panoramic mode of the Planmeca ProMax 3D Mid CBCT unit (Planmeca, Helsinki, Finland) with standard exposure settings used in clinical practice (60 kV, 2 mA, and maximum FOV). An automated calculator algorithm was developed in MATLAB platform. Two parameters associated with panoramic image distortion such as balls diameter and distance between middle and tenth balls were measured. These automated measurements were compared with manual measurement using the Planmeca Romexis and ImageJ software. The findings showed smaller deviation in distance difference measurements by proposed automated calculator (ranged 3.83 mm) as compared to manual measurements (ranged 5.00 for Romexis and 5.12 mm for ImageJ software). There was a significant difference (p < 0.05) on the mean measured ball diameter between automated and manual measurement. For ball diameter measurement, there is a moderate positive correlation between automated measurement with the manual measurements (r = 0.6024 and r = 0.6358 for Romexis and ImageJ, respectively). However, there is a negative correlation between automated measurement for the distance difference with manual methods (r = −0.3484 and r = −0.3494 for Romexis and ImageJ, respectively). There was a good approximation between automated and ImageJ measurement of ball diameter in comparison to reference value. In conclusion, the proposed automated calculator provides faster method with an accurate and acceptable results for daily-basis image quality test in dental panoramic mode of a Dental CBCT imaging system in comparison to current manual method. An automated calculator is recommended for image distortion analysis on phantom images in routine image quality assessment for dental panoramic mode of Dental CBCT imaging system that may involve analysis of large image datasets. It offers improvement in routine image quality practice in term of time and accuracy. [ABSTRACT FROM AUTHOR]

Photoacoustic (PA) imaging has gained much attention, providing structural and functional information in combination with clinical ultrasound (US) imaging systems. 2D PA and US imaging is easily implemented, but its heavy dependence on operator skills makes 3D imaging preferable. In this study, we propose a panoramic volumetric clinical PA and US imaging system equipping a handheld imaging scanner weighing 600 g and measuring 70 × 62 × 110 mm3. Multiple PA/US scans were performed to cover a large field-of-view (FOV), and the acquired PA/US volumes were mosaic-stitched after manually correcting the positions and rotations in a total of 6 degrees of freedom. PA and US maximum amplitude projection images were visualized online, while spectral unmixed data was quantified offline. The performance of the system was tested via tissue-mimicking phantom experiments. The system’s potential was confirmed in vivo by panoramically imaging vascular networks in human arms and necks, with FOVs of 331 × 38 and 129 × 120 mm2, respectively. Further, we quantified hemoglobin oxygen saturation levels in the radial artery, brachial artery, carotid artery, and jugular vein. We hope that this system can be applied for various clinical fields such as cardiovascular imaging, dermatology, vascular surgery, internal medicine, and oncology.

Background and purpose: Early diagnosis of jaw lesions is of great importance, especially in children. The aim of the present study was to investigate the frequency of jaw lesions in panoramic radiography of children (5-12 years old) in north of Iran. Materials and methods: In this study, 1000 panoramic images of children attending oral radiology centers (2012-2019) in north of Iran were studied during one year. Information, including the age, gender, and presence or absence of any jaw lesion were extracted from the radiographic images of patients. Data analysis was carried out in SPSS V22 applying Chi-square. Results: Out of 1000 panoramic images, 188 (18.8%) were found with jaw lesions. The mean age of children with these lesions was 8.64±2 years. Radiolucent lesions (in 185 images) were more frequent than radiopaque lesions. Conclusion: Radiolucent lesions were more of periapical lesions [ABSTRACT FROM AUTHOR]

The panoramic annular lens (PAL) is renowned for providing simultaneous vision of the panoramic space. However, its inherent central blind area is a significant drawback. In this study, we aim to harness the benefits of the PAL while mitigating its limitations by proposing a dual-channel panoramic zoom system without a central blind area. The introduction of a positive front lens group for secondary imaging is a critical aspect of our design, which is guided and substantiated by our mathematical imaging model. The results from our design affirm the practicality and effectiveness of the secondary imaging. This design can achieve a zoom ratio of 1. 46 × and a maximum field of view (FoV) range of 71 ° ∼ 100 ° , enabling zooming from front to rear. Exemplifying compactness, our system measures just 60 mm in total length, while providing a high-resolution output, as indicated by a modulation transfer function exceeding 0.3 at 200 lp/mm. With an F − θ distortion of less than 3.3%, the system maintains low levels of distortion. The analysis is instructive and the design shows potential in situations that necessitate compliance with size and resolution requirements. • A mathematical model provides efficient guidance for panoramic zoom system design. • Simultaneous front and side channel zooming eliminates the blind area during zooming. • Secondary front imaging eases optimization and preserves consistent direction. [ABSTRACT FROM AUTHOR]

3D imaging based on single-photon avalanche diode (SPAD) arrays is of interest in many applications. Limited by the small array size and low fill-factor of the available SPAD array, it is difficult for SPAD array-based lidars to achieve high-resolution and high-quality 3D images currently. Here, we propose a sub-pixel continuously scanning panoramic 3D imaging method. This method uses sub-pixel scanning to increase spatial resolution and employs accumulating photon counts at the different pixel of the array for the same target point to improve 3D image quality. We have established an experimental system based on a 32 × 32 SPAD array and a diffraction optical element (DOE) with 32 × 32 beamlet. By sub-pixel scanning for a target 3 m away and accumulating photon counts, we demonstrated that the spatial resolution has been improved from 3 mm to 0.33 mm and the 3D image quality has been improved evidently.

For the gastroscopic examination of the stomach, the restricted field of view related to the „keyhole“-perspective of the endoscope is known to be a visual limitation. Thus, a panoramic extension can enlarge the field of vision, supports the endoscopist during the examination, and ensures that all of the inner stomach walls are visually inspected. To compute such a panorama of the stomach, knowledge about the geometry of the underlying structure is required. Structure from motion an approach to reconstruct the necessary information about the 3D-structure from monocular image sequences as provided by a gastroscope. We examine and evaluate an existing deep neuronal network for stereo reconstruction, in order to approximate the geometry of stomach parts from a set of consecutive acquired image pairs from gastroscopic videos.

The C-arm X-ray system is a common intraoperative imaging modality used to observe the state of a fractured bone in orthopedic surgery. Using C-arm, the bone fragments are aligned during surgery, and their lengths and angles with respect to the entire bone are measured to verify the fracture reduction. Since the field-of-view of the C-arm is too narrow to visualize the entire bone, a panoramic X-ray image is utilized to enlarge it by stitching multiple images. To achieve X-ray image stitching with feature detection, the extraction of accurate and densely matched features within the overlap region between images is imperative. However, since the features are highly affected by the properties and sizes of the overlap regions in consecutive X-ray images, the accuracy and density of matched features cannot be guaranteed. To solve this problem, a heterogeneous stitching of X-ray images was proposed. This heterogeneous stitching was completed according to the overlap region based on homographic evaluation. To acquire sufficiently matched features within the limited overlap region, integrated feature detection was used to estimate a homography. The homography was then evaluated to confirm its accuracy. When the estimated homography was incorrect, local regions around the matched feature were derived from integrated feature detection and substituted to re-estimate the homography. Successful X-ray image stitching of the C-arm was achieved by estimating the optimal homography for each image. Based on phantom and ex-vivo experiments using the proposed method, we confirmed a panoramic X-ray image construction that was robust compared to the conventional methods. [ABSTRACT FROM AUTHOR]

Optical coherence tomography (OCT) is a noninvasive medical imaging modality, which provides highresolution transectional images of biological tissue. However, its potential is limited due to a relatively small field of view. To overcome this drawback, we describe a scheme for fully automated stitching of multiple 3D OCT volumes for panoramic imaging. The voxel displacements between two adjacent images are calculated by extending the Lucas-Kanade optical flow a lgorithm to dense volumetric images. A RANSAC robust estimator is used to obtain rigid transformations out of the resulting flow v ectors. T he i mages a re t ransformed into the same coordinate frame and overlapping areas are blended. The accuracy of the proposed stitching scheme is evaluated on two datasets of 7 and 4 OCT volumes, respectively. By placing the specimens on a high-accuracy motorized translational stage, ground truth transformations are available. This results in a mean translational error between two adjacent volumes of 16.6 ± 0.8 μm (2.8 ± 0.13 voxels). To the author’s knowledge, this is the first reported stitching of multiple 3D OCT volumes by using dense voxel information in the registration process. The achieved results are sufficient for providing high accuracy OCT panoramic images. Combined with a recently available high-speed 4D OCT, our method enables interactive stitching of hand-guided acquisitions.

The maintenance of underwater infrastructures and equipment remains dominated by manual operation, resulting in high costs and safety concerns. Recent advances in adsorptive-operating robots and intelligent controls offer new opportunities for underwater engineering operations. However, the universality and automation of robots are insufficient to support large-scale commercial applications. This review focuses on the fundamental design aspects in terms of adsorption, locomotion, visual observation, control, and autonomy. The approaches employed over the past two decades that enable robots to adsorb stably, locomote smoothly, make clear observations, and operate efficiently are described and compared. Robots with different applications are systematically introduced to illustrate the popular topics and value of research. This review aggregates these studies with the aim of revealing the state-of-the-art in underwater adsorptive-operating robots, and discussing future trends in this field. • This review discusses the state-of-the-art and future trends of UAORs. • The designs and performance of different adsorption methods for UAORs are reviewed. • The designs and performance of multiple locomotion methods for UAORs are reviewed. • Effective visual observation, control and autonomous technologies are presented. • The practical performance of UAORs with diverse designs are reviewed and compared. [ABSTRACT FROM AUTHOR]

We present here a comprehensive imaging theory about cone mirrors in a single-view-point (SVP) configuration and show that an SVP cone mirror catadioptric system is not only practical but also has unique advantages for certain applications. We show its merits and weaknesses and how to build a workable system.

Purpose: Lead shielding in the forms of thyroid straps and apron are known as protection devices in medical imaging. Recent data and guidelines do not recommend the routine use of lead shielding in dentistry imaging even for pregnant women. This study was conducted to investigate whether the application of these shielding is appropriate in our dental radiography. Materials and Methods: The study was conducted in five dental radiography centers that performed panoramic and intra oral imaging. A questionnaire consisting of five items was developed and technicians were asked to fill it out for a period of one month. Results: The results of this study showed that 72% of children and 70.3% of adults received protection by thyroid shielding. For 24% of children and 24.7% of adults no shielding was reported. In panoramic imaging of 55.5% children and 14.4% adult, thyroid shielding was used. Apron was applied for 33.3% of children and 54.4% of adults. No shielding was used for 11.1% of children and 30% of adults. Apron shielding in panoramic imaging for children was 33.3% and for adults 54.4% Conclusion: The results of this survey showed, in general, a routine behavior exists in shielding application for dental radiography which has not been updated. Then, it seems that there is a need for updating knowledge regarding appropriate use of thyroid and apron shielding for this imaging modality.

The pterygopalatine fossa is a small area between the posterior wall of the maxillary sinus and the anterior surface of the pterygoid process of the sphenoid bone. The pterygopalatine fossa can be seen clearly on panoramic imaging. We present the case of a 57-year-old man who exhibited right pterygopalatine fossa expansion on panoramic imaging. Computed tomography (CT), magnetic resonance imaging (MRI), and panoramic imaging all showed a tumor at the right pterygopalatine fossa in this patient. CT indicated that the tumor replaced right retromaxillary fat and displaced the posterior wall of the maxillary sinus. On MRI, the tumor showed intermediate signal intensity at the paranasal area on T1-weighted images, and variable intermediate and high signal intensities on fat-suppressed T2-weighted images. It was eventually diagnosed as a schwannoma. Thus, panoramic imaging can be used for disease screening at the posterior border of the maxilla. Our conclusion is based on this report of a patient with a schwannoma at the posterior wall of the maxillary sinus, which panoramic imaging revealed to have pterygopalatine fossa expansion. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine whether cone beam computed tomography (CBCT) before mandibular third molar removal can improve the risk assessment for neurosensory disturbances of the inferior alveolar nerve (IAN) compared to panoramic radiography (PAN). One hundred and six mandibular third molars examined by PAN and CBCT were removed. A temporary sensory disturbance of the IAN was present in 20 cases; a permanent disturbance was found in one case. Three blinded observers assessed radiographic risk factors in PAN and CBCT images. Positive (PPV) and negative (NPV) predictive values and positive (LR+) and negative (LR−) likelihood ratios were calculated for all parameters for all observers. Inter-observer reproducibility was expressed as both the percentage accordance and the kappa-statistic. Generally, the PPV and LR + were the same for PAN and CBCT, and there was good inter-observer reproducibility. The highest PPV and LR + for PAN were found when part of the roots were positioned inferior to the lower white border line of the canal, and for CBCT when the canal was positioned between the roots of the tooth. In conclusion, parameters assessed in PAN and CBCT are not reliable risk factors for neurosensory disturbances of the IAN, and CBCT appears not to improve the risk assessment. [ABSTRACT FROM AUTHOR]

We introduce a novel method to automatically adjust camera exposure for image processing and computer vision applications on mobile robot platforms. Because most image processing algorithms rely heavily on low-level image features that are based mainly on local gradient information, we consider that gradient quantity can determine the proper exposure level, allowing a camera to capture the important image features in a manner robust to illumination conditions. We then extend this concept to a multi-camera system and present a new control algorithm to achieve both brightness consistency between adjacent cameras and a proper exposure level for each camera. We implement our prototype system with off-the-shelf machine-vision cameras and demonstrate the effectiveness of the proposed algorithms on practical applications, including pedestrian detection, visual odometry, surround-view imaging, panoramic imaging, and stereo matching. [ABSTRACT FROM AUTHOR]

In order to reduce the volume of a panoramic optical system, a four-channel infrared dual-band panoramic imager was designed using spatial multicamera image mosaicking. Each optical system of the imaging channel was designed in a double imaging configuration with an F-number of 2, working bands of MWIR 3 to 5 μm and LWIR 8 to 12 μm, and a full field of view (FOV) of 122 deg. By adopting refractive-diffractive hybrid optical elements and introducing aspheric designs, the system was made to achieve temperature compensation from -40°C to 60°C by means of optical passive athermalization. Results indicate that the system attained almost 100% cold stop efficiency. At the Nyquist frequency of 18 lp/mm, the modulation-transfer-function (MTF) of the MWIR system was higher than 0.70 at the edges of the FOV, whereas the MTF of LWIR system was greater than 0.35 for the same condition, both approaching the diffraction limit. [ABSTRACT FROM AUTHOR]

Copyright of International Journal of Computerized Dentistry is the property of Quintessence Publishing Company Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With the rapid development of the virtual reality industry, one of the bottlenecks is the scarcity of video resources. How to capture high-definition panoramic video with depth information and real-time stereo display has become a key technical problem to be solved. In this paper, the optical optimization design scheme of panoramic imaging based on binocular stereo vision is proposed. Combined with the real-time processing algorithm of multi detector mosaic panoramic stereo imaging image, a panoramic stereo real-time imaging system is developed. Firstly, the optical optimization design scheme of panoramic imaging based on binocular stereo vision is proposed, and the space coordinate calibration platform of ultra-high precision panoramic camera based on theodolite angle compensation function is constructed. The projection matrix of adjacent cameras is obtained by solving the imaging principle of binocular stereo vision. Then, a real-time registration algorithm of multi-detector mosaic image and Lucas-Kanade optical flow method based on image segmentation are proposed to realize stereo matching and depth information estimation of panoramic imaging, and the estimation results are analyzed effectively. Experimental results show that the stereo matching time of panoramic imaging is 30 ms, the registration accuracy is 0.1 pixel, the edge information of depth map is clearer, and it can meet the imaging requirements of different lighting conditions.

This study was designed to examine the prevalence of previously experienced maxillofacial injuries in athletes engaging in combat sports and to investigate any possible radiologic findings of dental and bone pathology that can be caused by repetitive head (jaw) impacts. Thirty-two boxers and thirty-two taekwondo athletes and sex- and age-matched non-athletes control group participated in the study. A special questionnaire was used with questions on previously experienced maxillofacial trauma and mouthguard use. Temporomandibular dysfunctions were also examined. Panoramic radiographs of the athletes and control group were examined by two radiologists. Both athlete groups experienced significantly more dental (p lt; 0.059), temporomandibular joint (TMJ) (p lt;0.05) and nasal (p lt;0.05)injury than non-athletes. In addition, boxers experienced more TMJ (p lt;0.05)and nasal injury (p lt;0.05) than taekwondo players. Although most of the athletes (96.9%) wore mouthguards in sports competitions, few of them (9.4%) used the guards while training. Temporomandibular dysfunction (TMD) was mostly examined in combat sport athletes (p lt;0.05; X2=10.494).There was no statistically significant difference between the athletes and the control group for the possible radiologic findings of dental and bone pathology that could be caused by the repetitive head (jaw) impacts on panoramic radiographs (p gt;0.05). Athletes engaging in combat sports, especially boxers, have significantly more maxillofacial injuries. Therefore, they should be educated to use more safety and protective guards not only in competitions but also in training to prevent maxillofacial injury. This is the first report of panoramic findings on dental and bone pathology that could be caused by repetitive head (jaw) impacts.

The ground-based arc-scanning synthetic aperture radar (ArcSAR) is capable of 360° scanning of the surroundings with the antenna fixed on a rotating arm. ArcSAR has much wider field of view when compared with conventional ground-based synthetic aperture radar (GBSAR) scanning on a linear rail. It has already been used in deformation monitoring applications. This paper mainly focuses on the accurate and fast imaging algorithms for ArcSAR. The curvature track makes the image focusing challenging and, in the classical frequency domain, fast imaging algorithms that are designed for linear rail SAR cannot be readily applied. This paper proposed an efficient frequency domain imaging algorithm for ArcSAR. The proposed algorithm takes advantage of the angular shift-invariant property of the ArcSAR signal, and it deduces the accurate matched filter in the angular-frequency domain, so panoramic images in polar coordinates with wide swath can be obtained at one time without segmenting strategy. When compared with existing ArcSAR frequency domain algorithms, the proposed algorithm is more accurate and efficient, because it has neither far range nor narrow beam antenna restrictions. The proposed method is validated by both simulation and real data. The results show that our algorithm brings the quality of image close to the time domain back-projection (BP) algorithm at a processing efficiency about two orders of magnitude better, and it has better image quality than the existing frequency domain Lee’s algorithm at a comparable processing speed.

Panoramic imaging has important applications in virtual reality. Current panoramic imaging only can create a 360∘ panorama but cannot change the focal surface or support depth cues. In this paper, we present a variable aperture panoramic imaging method based on a two-sphere panorama model (TSPM). Based on this model, we propose a definition of Aperture for TSPM, which can precisely control the depth of field (DOF) of panoramas. With same aperture size and focus distance, two similar panoramas could be synthesized from a range of capture camera configurations. Extensive experiments have been carried out to validate our panoramic imaging method. [ABSTRACT FROM AUTHOR]

To solve the systematic errors caused by lens machining errors, optical distortion and alignment errors, the calibration ol catadioptric panoramic inlrared imaging system is presented. Based on the fabrication of infrared target, the calibration method based on planar grid points is studied, including the extraction of feature points based on morphology, system parameter selection, and the minimum value of the objective function using Jacobi iteration method. Experimental results show that the calibration method can accurately obtain 10 internal parameters such as mirror surface parameter, radial and tangential distortion parameters and camera model parameters, and 7 external parameters such as translation parameters and rotation parameters. The re-projection error is controlled within 3 pixels, and this calibration method is important for the determination of the imaging position. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin: Newsletter of the Society of Radiographers of Slovenia & the Chamber of Radiographers of Slovenia is the property of Slovenian Society of Radiographers and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introduction The accuracy of position of miniscrew implants is utmost important for implant success. In this study, we investigated whether the routine 2D ortopantomogram can be used to assess the accuracy in the placement of miniscrews as compared with 3D radiography and direct measurements on a dried skull. Methods: Miniscrew implants were placed in between premolar and molar areas at an angulation of 40΀ to 50΀ for maxilla and 10΀ to 20΀ for mandible on dried skull. Linear and angular measurements were taken on these dried skulls using direct method, ortopantomogram and 3D radiography. Analysis of variance (ANOVA) and multiple comparison Tukey′s test were used to test for differences in three methods. Results: The results shows 20% vertical magnification for maxilla and mandible whereas horizontal measurements shows 54.2% of variations in maxilla and 27.1% of variations in mandible on panoramic radiographs as compared to direct method and 3D radiography. Angular measurements show 9΀ to 10΀ of variation on panoramic radiographs as compared to direct method and 3D radiography for both maxilla and mandible. Conclusion: Ortopantomogram shows more variations on linear and angular measurements as compared to direct method and 3D radiography whereas direct method and 3D radiography show no difference. But, we can calculate the angulations of miniscrew implant placement by angular regression model.

In order to create a perspective drawing on a curved surface, the quadraturista had to face, in addition to the flat perspective drawing issues, also the ones related to the mapping of the three dimensional surface. In literature we can find two methodologically different approaches related to the flat design transposition procedures onto the curved surface: indirect and direct method. The indirect one, partially described by Vignola, is based on the use of pre-designed cartoons on the ground. The direct one, described by Andrea Pozzo, is based on the direct projection of a flat grid onto the curved surface. Both the ceiling painting of the Church of San Matteo in Pisa and the parietal one of the Church of S. Caterina in Livorno show, even if observed from the privileged viewpoints, some irregularities. These irregularities, as we are going to show, are actually the consequences of the method applied for the transposition of the flat drawings onto the curved surfaces. [ABSTRACT FROM AUTHOR]

This paper presents a novel panoramic hyperspectral stereo imaging system with depth map estimation capability. Images are collected from two line scan hyperspectral cameras in stereo configuration, while the platform is rotating. The proposed system combines the strengths of hyperspectral, stereo, and panoramic imaging. In addition, the proposed system uses passive sensors and hence does not need any radiation source, unlike LiDAR-based systems. In this paper, the proposed system, which captures hyperspectral data from 400 to 1000 nm wavelengths, is introduced, the stereo calibration procedure is described, corresponding analytic analyses are carried out with relation to rotating line-scan camera theory, and critical system parameters and aspects are addressed. In addition, a novel multiband stereo matching approach, which introduces multiband Census transform and SAD-based cost aggregation to stereo matching literature, is proposed. Experimental results are evaluated using two hyperspectral datasets, and the performance of the proposed algorithm is compared with the performance of several prominent matching algorithms available in the literature. A LiDAR-based system is used to enable an analysis of depth information accuracy. The experimental results show the enhanced matching and depth estimation performance of the proposed matching approach over standard stereo methods, and the consistency of depth values between LiDAR and the proposed system. The proposed system, which combines the strengths of panoramic imaging and stereo imaging with the high spectral resolution of hyperspectral cameras, uses passive imaging solutions and is fit to be used in applications requiring depth computation, target detection, and change detection. [ABSTRACT FROM PUBLISHER]

Panoramic cameras have become popular because they provide impressive and immerse experience of the scene and allow several interesting applications. Among the large variation of panoramic camera systems, we have focused on concentric panoramic imaging with a frame camera. In order to establish the concentric image acquisition, the camera mount must be calibrated so that the projection centre of the camera is located at the rotation centre of the mount. For this purpose, we developed a novel mount calibration method, which allows an accurate recovery of the rotation centre in two image acquisition steps. In addition, we have built a motorized camera mount that can self-calibrate the camera position within the mount, given the previously solved rotation centre, and then be used to automatically capture panoramic images. Hence, we have streamlined the previously laborious manual phase of iterative position calibration, but also automated the capturing of panoramic images. For validation purposes, reference results from a conventional manual mount are provided. In the case of non-motorized mount, the average distance between the projection centre of the camera and the rotation centre of the mount was 0.253 mm and the standard deviation was 0.161 mm. For the motorized mount, the corresponding average distance and standard deviation were 0.549 mm and 0.404 mm, respectively. [ABSTRACT FROM AUTHOR]

Objectives: This epidemiological study aimed to analyse economical and societal consequences in Denmark if CBCT is used routinely as a diagnostic method before removal of the mandibular third molar. Furthermore, the aim was to calculate the excess cancer incidence from this practice. Methods: 17 representative dental clinics in the regions of Denmark were visited by two observers, who registered the total number of patients in each clinic, the number of removed mandibular third molars from patients' files together with the age and gender of these patients. The data were collected from 2008 to 2014. The total number of removed mandibular third molars in Denmark each year was derived from the collected data and information on patients' contacts with dentists from Statistics Denmark as a sum of contributions from each region. The contribution of a region was obtained as the number of removed mandibular third molars in the selected clinics in the region times the ratio of the number of patients in the selected clinics in the region to the total number of patients with contact to a general practitioner in the region in 2011. Existing knowledge on the costs for panoramic and CBCT imaging was used to calculate total costs. The cancer incidence was calculated from lifetime attributable risk curves based on linear risk assumptions. Results: The selected clinics included 109,686 patients, and 1369 mandibular third molars had been surgically removed. Using data from Statistics Denmark gave an estimated annual number of removed mandibular third molars of 36,882 at a total cost of €6,633,400. The additional cancer incidence was estimated to be approximately 0.46 per year. Conclusions: The data should be used in a cost-effectiveness analysis of the clinical efficacy of CBCT imaging before removal of mandibular third molars. [ABSTRACT FROM AUTHOR]