Camera Lens Research Articles

Lighting measurement with a 360° panoramic camera: Part 2 – Applications

This study developed a 360° field of view (FOV) lighting measurement method with the aid of the Ricoh Theta Z1 panoramic camera. As versatile lighting information from all viewing directions within 360° FOV can be retrieved from a single 360° high dynamic range image, this new method improves the lighting measurement efficiency. Potential unique applications are reported in the present paper as Part 2 of this study. Corresponding lighting information covers a 360° luminance map, a 360° coefficient of variation map of luminance (CVL), a 360° luminance contrast ( C1) map or ratio ( Cr1) map between any interested target located at the viewing direction and its near background, a 360° luminance contrast ( C2) map or ratio ( Cr2) map between the same target and the ambient environment and a 360° illuminance map and its single coefficient of variation of illuminance (CVE) value of all illuminances on the illuminance map. All lighting information is measured at the same point with 360° viewing directions to analyse the uniformity and continuity of the lighting environment. An angular distance weighted illuminance calibration is used to correct possible mismatched white balance of the front and rear camera lenses in a scenario with multiple light sources of dramatically different Correlated Colour Temperature (CCTs). All customized camera-control and data treatment programs, including MATLAB code and Python programs, are uploaded to the project GitHub site for online sharing.

Proof of concept study: a novel mobile in-canopy imaging system for detecting symptoms of fungal diseases in cereals

To recognize species-specific symptoms of plant diseases automatically, a near surface imaging at a sub-millimeter scale is necessary. Current investigations relate to an inspection of the upper visible crop parts using camera imaging from above the canopy. The paper presents primarily results using a sensor system, which is operating inside the canopy to monitor the vertical health status of winter wheat. This in-canopy sensor is also inspecting lower, invisible crop parts. With this technology a spatial and temporal precise crop protection—a future spraying of only the infected field parts would be possible. A commercially available camera with an NIR filter was attached to a vertical rod. To protect the camera while moving through the crop, it was installed inside a tube. This tube guaranteed a constant distance to the crop tissue so that it did not cover the camera lens. The mobile device was flexibly mounted on the back, three-point linkage of a tractor. In this first use example, the sensor was operated inside the crop canopy to inspect the lower leaves and directly at the canopy surface to inspect the upper leaves and the ears. In the images of the leaves inside the canopy, symptoms of tan spot (anamorph Drechslera tritici-repentis (Died.) Shoemaker) were clearly visible at flowering. When the camera was operated at the canopy level, black ears (caused by black point/kernel smudge/black head molds) were visible at milk ripeness.

Correcting projector lens distortion in real time with a scale-offset model for structured light illumination.

In fringe projection profilometry, inevitable distortion of optical lenses decreases phase accuracy and decreases the quality of 3D point clouds. For camera lens distortion, existing compensation methods include real time look-up tables derived from the related parameters of camera calibration. However, for projector lens distortion, so far, post-undistortion methods iteratively correcting lens distortion are relatively time-consuming while, despite avoiding iteration, pre-distortion methods are not suitable for binary fringe patterns. In this paper, we aim to achieve real-time phase correction for the projector by means of a scale-offset model that characterizes projector distortion by four correction parameters within a small-enough area, and thus we can speed up the post-undistortion by looking up tables. Experiments show that the proposed method can suppress the distortion error by a factor of 20 ×, i.e., the error of root mean square is less than 45 µm/0.7‰, while also proposed improving the computation speed by a factor of 50× over traditional iterative post-undistortion.

Design and implementation of an augmented reality mobile application for navigating ATM counters (AR-ATM)

PurposeThis paper aims to bring in augmented reality (AR) into navigation systems to rectify the issues mentioned. This paper proposes an AR enhanced navigation system for location automated teller machine (ATM) counters (AR-ATM) and branches of banks based on user’s choice. Upon selecting the ATM, the navigational path to the destination is drawn from the current location, thereby the user can reach the ATM through the optimal path.Design/methodology/approachTraditional navigation systems require users to map with the real world environment as and when required and also may lead to incorrect path due to minor difference in distance. The traditional navigation systems’ also does not take into consideration the ergonomics and safety of the user.FindingsIn this system, a camera lens is used, which is directed down the street at eye level and the application displays the location of ATMs and bank branches and also provides information about the locations like distance and time through the AR superimposed object.Originality/valueThe application also provides indoor navigation, especially in a multi-storeyed building. Experiments are performed on smartphones that support AR, and the results are promising with no lag in time frame of the real object and virtual object. To determine the factors that regulate the suggested AR tracking mechanism, a quantitative evaluation of the experimental data is also performed. The testing of implemented AR-ATM from the standpoint of end-users is undertaken to evaluate real-time usage comfortability, and the results have been determined to be extremely satisfactory.

Freeform wide-angle camera lens enabling mitigable distortion.

Allowing natural scenes as well as maximizing field of view (FoV) can benefit from the minimization of distortion for the wide-angle camera. The wide-angle camera utilizing freeform surfaces for mitigating distortions, either barrel distortion or pincushion distortion, is therefore of interest. In this paper, the designs of using all-aspherical surfaces and aspherical surfaces combined with freeform surfaces are investigated. To minimize the deviation before and after converting from aspherical surfaces to freeform surfaces, a mathematical conversion scheme is derived. By applying it to the design example, the methodology is shown to be effective in the case of an optical system with a large number of aspherical/freeform surfaces. Additionally, custom freeform analysis tools are developed for quantitative analysis and visualization of the critical characteristics of optical performance, namely, a 2D lateral color field map, 2D relative illumination field map, 2D spot radius field map, and 2D average modulation transfer function (MTF) field map. Compared to classical all-aspherical design, simulation results show that freeform design has the capability to reduce distortion, and other performances such as relative illumination, spot size, and MTF can also be improved, even though there are some compromises on the peripheral FoV. The design approach will have potential important research and application values for lens systems utilized in miniature camera lenses, especially the wide FoV capability.

Ultraviolet Fluorescence Photography-Choosing the Correct Filters for Imaging.

Ultraviolet (UV) fluorescence is a valuable tool for the imaging of a wide range of subjects. Like all imaging techniques, the key to success depends on the correct choice of equipment and approach used. In fluorescence photography, a filter is placed in front of the camera lens to block unwanted short-wavelength light from entering the camera, which would compromise the image. However, some filters exhibit fluorescence under UV light and can therefore have the potential to produce a color cast on the image. Filters also vary in how well they block unwanted light. A range of commonly used optical filters was assessed for fluorescence under UV light, and their optical transmission between 250 nm and 800 nm was measured. Finally, a simple method to enable the researcher to determine the fluorescence of the filters that they are using or wish to use for their work is described. The results indicate that the filters tested demonstrated a wide range of fluorescence under UV light and varying degrees of UV blocking. Some filters tested had equivalent or reduced fluorescence compared to Schott KV-418, which is a widely used, but, unfortunately, no longer manufactured UV blocking filter commonly used for fluorescence photography.

A New Modified Video Solution System for Neuroendoscopic Procedures

Background and Aim: Today, neuroendoscopic surgery is gaining popularity because of its minimal damage to normal structures, fewer complications, and excellent clinical results. Using an endoscope and related instruments, surgeons can perform complex surgeries through small incisions, especially for minimally invasive spinal and brain surgeries. Neuroendoscopic systems are currently costly and not portable. Our new video solution is portable at a lower cost and can display and record images in 4K resolution. Methods and Materials/Patients: We modified the GoPro Hero 6 camera to serve our purpose. By detaching the original camera lens and its front part and replacing the removed parts with a new design, we made a C-mount camera that can connect to a standard C-mount coupler and various common scopes. For color correction, we used an IR-cut filter in front of the camera sensor. Results: By changing some parts of the camera and connecting it to a C-mount coupler and a scope lens, we made a small, portable neuroendoscope that displays and records images in clear, sharp, high resolution, with a high frame rate. Conclusion: The modified GoPro camera can be used as an alternative and unexpansive neuroendoscope system for education or treatment in medical centers in developing countries.

Describing the Challenges of Prehospital Rapid Sequence Intubation by Macintosh Blade Video Laryngoscopy Recordings

Structured review of video laryngoscopy recordings from physician team prehospital rapid sequence intubations (RSIs) may provide new insights into why prehospital intubations are difficult. The aim was to use laryngoscope video recordings to give information on timings, observed features of the airway, laryngoscopy technique, and laryngoscope performance. This was to both describe prehospital airways and to investigate which factors were associated with increased time taken to intubate. Sydney Helicopter Emergency Medical Service (HEMS; the aeromedical wing of New South Wales Ambulance, Australia) has a database recording all intubations. The database comprises free-text case detail, airway dataset, scanned case sheet, and uploaded laryngoscope video. The teams of critical care paramedic and doctor use protocol-led intubations with a C-MAC Macintosh size four laryngoscope and intubation adjunct. First-pass intubation rate is approximately 97%. Available video recordings and their database entries were retrospectively analyzed for pre-specified qualitative and quantitative factors. Prehospital RSI video recordings were available for 385 cases from January 2018 through July 2020. Timings revealed a median of 58 seconds of apnea from laryngoscope entering mouth to ventilations. Median time to intubate (laryngoscope passing lips until tracheal tube inserted) was 35 seconds, interquartile range 28-46 seconds. Suction was required prior to intubation in 29% of prehospital RSIs. Fogging of the camera lens at time of laryngoscopy occurred in 28%. Logistic regression revealed longer time to intubate was associated with airway soiling, Cormack-Lehane Grade 2 or 3, multiple bougie passes, or change of bougie. Video recordings averaging 35 seconds for first-pass success prehospital RSI with an adjunct give bed-side "definitions of difficulty" of 30 seconds for no glottic view, 45 seconds for no bougie placement, and 60 seconds for no endotracheal tube placement. Awareness of apnea duration can help guide decision making for oxygenation. All emergency intubators need to be cognizant of the need for suctioning. Improving the management of bloodied airways and bougie usage may reduce laryngoscopy duration and be a focus for training. Video screen fogging and missed recordings from some patients may be something manufacturers can address in the future.

Exhibition Review: The New Woman Behind the Camera

Exhibition Review: <i>The New Woman Behind the Camera</i>

Effect of scanner lens on lateral response artefact in radiochromic film dosimetry

Radiochromic film is a good dosimeter choice for patient QA for complex treatment techniques because of its near tissue equivalency, high spatial resolution and established method of use. Commercial scanners are typically used for film dosimetry, with Epson scanners being the most common. Radiochromic film dosimetry is not straightforward having some well-defined problems which must be considered, one of the main ones being the Lateral Response Artefact (LRA) effect. Previous studies showed that the contributing factors to LRA are from the structure of the active ingredients of the film and the components and construction of the flatbed scanner. This study investigated the effect of the scanner lens on the LRA effect, as part of a wider investigation of scanner design effects and uncertainties. Gafchromic EBT3 films were irradiated with 40 × 40 cm2 field size 6 MV beams. Films were analysed using images captured by a Canon 7D camera utilising 18 mm, 50 mm and 100 mm focal length lenses compared to images scanned with a conventional Epson V700 scanner. The magnitude of the LRA was observed to be dependent on the focal length of the lens used to image the film. A substantial reduction in LRA was seen with the use of the 50 mm and 100 mm lenses, by factors of 3–5 for the 50 mm lens and 4–30 for the 100 mm lens compared to conventional desktop scanner techniques. This is expected to be from the longer focal length camera lens system being able to collect more light from distant areas compared to the scanner-based system. This provides an opportunity to design film dosimetry systems that minimise this artefact.

GAN-Based Video Denoising with Attention Mechanism for Field-Applicable Pig Detection System.

Infrared cameras allow non-invasive and 24 h continuous monitoring. Thus, they are widely used in automatic pig monitoring, which is essential to maintain the profitability and sustainability of intensive pig farms. However, in practice, impurities such as insect secretions continuously pollute camera lenses. This causes problems with IR reflections, which can seriously affect pig detection performance. In this study, we propose a noise-robust, real-time pig detection system that can improve accuracy in pig farms where infrared cameras suffer from the IR reflection problem. The system consists of a data collector to collect infrared images, a preprocessor to transform noisy images into clean images, and a detector to detect pigs. The preprocessor embeds a multi-scale spatial attention module in U-net and generative adversarial network (GAN) models, enabling the model to pay more attention to the noisy area. The GAN model was trained on paired sets of clean data and data with simulated noise. It can operate in a real-time and end-to-end manner. Experimental results show that the proposed preprocessor was able to significantly improve the average precision of pig detection from 0.766 to 0.906, with an additional execution time of only 4.8 ms on a PC environment.

Initial experimental multi-wavelength EEM (Excitation Emission Matrix) fluorescence lidar detection and classification of atmospheric pollen with potential applications toward real-time bioaerosols monitoring.

Fluorescence has the potential to identify the types of substances associated with aerosols. To demonstrate its usefulness in environmental studies, we investigated the use of Excitation-Emission-Matrix (EEM) fluorescence in lidar bioaerosol monitoring. First, the EEM fluorescence of cedar, ragweed, and apple pollens as typical bioaerosols found around our surroundings were measured using a commercial fluorescence spectrometer. We found that the patterns of fluorescence changed depending on the pollen type and excitation wavelength and it meant that studying these EEM fluorescence patterns was a good parameter for identifying pollen types. Then, we setup a simple EEM fluorescence lidar to confirm the usefulness in lidar bioaerosol monitoring. The lidar consisted of three laser diodes and one light emitting diode with output at 520 nm, 445 nm, 405 nm and 325 nm, respectively, an ultra violet camera lens as a receiver, and a fluorescence spectrum detection unit. Comparing the lidar simulation results with the EEM fluorescence dataset supported the possibility of performing bioaerosol monitoring using the EEM fluorescence lidar. Based on the results and the current technology, a feasible design of a bioaerosol detection EEM fluorescence lidar is proposed for future rel-time remote sensing and mapping of atmospheric bioaerosols.

The Spacing of a Message

In the 21st century, during the pandemic, as in any other time, people choose keywords to quash their anxieties, to ferment their uneasiness, to free themselves. We build bridges between the art of theater, physics and psychology, with the help of which to cancel the imposed distances, with variable dimensions – from 1.5 m to the... social ones. Appearance and resilience tend to measure our ability to withstand the unexpected closings and openings of theatrical encounters; in fact, they become ways of reflecting the dimension of each artist's desire to get involved, to express themselves, to respond to the needs of those around them - as each knows best, each with his craft. In this context, the definition of the theory of emerging evolution offers us a new perspective on creativity; the hybrid formulas of “theater-filming”, whatever the attached concept would be, carry with them the vibration of the “spontaneous and the unpredictable”. Applied theater is no exception. With or without dolls, it offers the chance for quick reformulations, focusing on the need of the receiver and the transmission of a message. Thus, The inner tree (Copacul interior) was transformed from an applicative theater show into a challenge in which artistic research took concrete forms. Firstly: message spacing; the road to the public passed through the narrowness of the camera lens. Unexpectedly, unlooked for, the dream meeting could only be fulfilled in digitized formulas. This perspective allows us to notice the opportunity of the unpredictable, which of the relationship body - puppet - projection has become a formula for training creativity, for reformulating stage expressiveness; this time art humbly serves the message.

Research on pose adaptive correction method of indoor rail mounted inspection robot in GIS Substation

This paper presents a multi degree of freedom rail mounted inspection robot in GIS Substation and its adaptive pose adjustment method. According to the operation requirements of GIS indoor inspection robot, the functional models of robot walking module, lifting module, execution monitoring module and intelligent control module are established. The robot has the functions of image, sound and infrared acquisition. Combined with the pose adjustment of the camera at the end of the robot, it can accurately collect most of the equipment instrument data with different pose, and provide data sample support for analyzing and judging whether the equipment has abnormal conditions. The experimental results show that the rail hanging multi degree of freedom inspection robot can successfully overcome the complex equipment structure and move the end effector to the appropriate inspection point. After being adjusted by its adaptive pose adjustment method, the distance between the camera and the dial plane is within the interval [13 cm, 18 cm], and the included angle between the camera lens and the instrument plane is within the interval [2o,7o], both of which can meet the requirements of meter reading accuracy in indoor patrol inspection of substation. Compared with manual inspection, the inspection time of the inspection robot proposed in this paper is reduced by more than 75%, and can meet the 24-hour uninterrupted regular inspection. It is of great significance to ensure the safe and stable operation of substation, reduce inspection error, reduce labor cost, and realize the remote, intelligent and standardized inspection of GIS Substation.

The effect of gamma-ray irradiation on polycarbonate sheets

In our study, we report on the effect of gamma-ray irradiation on four types of polycarbonate sheets. We used the panoramic gamma-radiation facility with 60Co source with applied doses from 1.38 to 100.50 kGy with the radiation dose rate 66.6 ± 6.3 Gy/h. To get knowledge on the needed properties, the prism coupling method was used for refractive indices measurement at six wavelengths (532.0, 654.2, 846.4,1308.2, 1549.1 and 1652.1 nm) and Sellmeier approximation with an infrared correction was used to estimate the refractive indices from 500 to 1700 nm. The transmission spectra were measured in the spectral range from 250 to 2150 nm and absorption coefficient and band gap Eg were calculated from transmission spectra. The chromaticity coordinates and influence of the gamma-irradiation were also studied. Our results proved that materials such as these can be used in gamma-radiation-exposed environments for optical components such as digital camera lenses, optical lenses, mirrors, prisms, optical waveguides, etc.

Capturing the Northern Lights

This article explores the influence of conventions set by The Photographic Atlas of Auroral Forms, published by the International Union of Geodesy and Geophysics (1930), on protocols employed at Arctic stations researching the aurora borealis during the Second International Polar Year (1932–1933). The atlas was created by a committee led by Professor Carl Størmer, the leading auroral scientist of the early twentieth century. It categorized auroral forms, established codes for viewing the phenomenon through the camera lens, and provided a multitude of carefully selected photographs to direct the reader. Responding to a call for greater emphasis on verticality in studies of twentieth-century atmospheric science, this paper addresses the vertical dimension as both a consideration in the process of visually documenting the fleeting and intangible forms of the aurora as well as a subject of study in its own right, in relation to altitude measurements of the phenomenon. With a focus on the specific instrumentation used, light is shed on the difficulties of calibration across polar stations, bodily comportments involved in viewing aurorae, and properties of the northern lights revealed through temporal distance from the display. In seeking to answer the methodological question of whether atlases reflect the reality of scientific practices, I analyze how The Atlas of Auroral Forms affected observational routines among Norwegian, British, Canadian, American, and Dutch polar year groups. Emphasis is placed on instances of divergence from its guidance to demonstrate that research practices do not always follow inexorably from an instructive text, even given the most favorable of conditions.

Study on quality detection of stone surface

Abstract With the continuous improvement for the safety of stone installation, the quality detection of its machined surface is also improving. But its surface crack was always a difficult problem in detection. In recent years, with the rapid development of image processing technology a new method to solve this problem can be realized. In this paper, CCD camera was used to detect the surface crack and roughness of stone slabs. The research about image correction and image enhancement was carried, so as to eliminate noise and protect the crack edge in the greatest extent. The improved threshold segmentation algorithm was used to segment image of linear fracture filtering. Mathematical morphology was applied to refinement of single pixel of crack in order to gain crack size. The CCD camera and micro lens are assembled as image sensors to enlarge the surface of stone and take a sample by many taking pictures. The surface profile of the tested stone slab is obtained by reconstruction method, and the surface roughness of stone slab is finally obtained by analysis and calculation. Through this research, a fast detection technology was realized, which solves the problems of low processing efficiency and high cost in production. The result shows certain theoretical value and practical application significance.

Application in optical design: Optimization for high intensity and aberration free camera lens system

The cost of a camera device has risen considerably in the last decade due to the optical lens element. Imaging system aberration is primarily caused by the different types of elements. The cost of an optical lens element is also related to the quality of the imaging system. The research proposes a unique optical design with reduced and optimized lens elements while maintaining high output quality. The research proposes the analysis and design of an optical imaging system with a reduced optical lens element. This paper looks at how sequential ray tracing algorithms use fine-tuned bespoke and commercial optical design and suggests more fine-tuning to improve imaging quality. Design stages also include automatic global synthesis, asphere expert, and glass expert, all of which must be correctly optimized to reduce error and improve performance. The proposed design is evaluated utilizing optical simulator analysis features such as the Modulation Transfer Function (MTF), Spot diagram and Quick ray aberration, and Error function to test its performance. The wavefront differential approach blends TOR (full form is needed) analysis for measuring the performance impact of manufacturing and assembly errors with diffraction MTF performance measurements. In both qualitative and quantitative terms, the proposed imaging system outperforms the existing imaging system.

Image Enhancement Techniques Using CNN

The most significant area in imaging study and processing is image processing technique. The major goal is to improve quality images artificially through other means. The images that are obtained at times through certain mediums may end up distorted making the image unclear. One option to enhance the image quality is to change camera lens, which is costly. Thus, an alternative is required. A conventional neural network (CNN) may give priority to distinct aspects in an image and differentiate between them. A clear review of the literature on a few CNN-based picture enhancing techniques is carried out

Through the “Camera Lens”: How Do Students Grasp the Future of Learning via Online Platforms?

During the COVID-19 pandemic, the academic world came into contact with a virtual learning environment that allows students and educators to leave the boundaries of space and time and maintain academic interactions at unrestricted times and sites. After three semesters of remote learning, there is a feeling that the return to universities and to closed spaces will deter students and that they will prefer remote learning. Studying from home spares valuable time, time otherwise wasted in traffic jams, as well as petrol and other expenses. Remote learning gives a feeling of freedom, comfort, flexible time, and a better sense of control over one&amp;rsquo;s studies than in the classroom. The current study, conducted about one year after the outbreak of the pandemic, examined students&amp;rsquo; background variables: gender, years of schooling, marital status, financial and employment status &amp;ndash; with the goal of exploring the association between these variables and students&amp;rsquo; preference for either face-to-face or digital teaching. It is evident from the research findings that after this experience of e-Learning neither of these two methods shows a clear advantage over the other. Was the e-Learning experience during the crisis a one-time, incidental event? Or perhaps, in light of the crisis, academic institutions should prepare for a different type of learning, one that combines face-to-face with digital learning? The study illuminates an issue that is confronting educational institutions in general and academic institutions in particular, i.e., preparations for teaching and learning in the post-crisis world, after the considerable upheaval to which we were subjected.