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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A smartphone camera reveals an ‘invisible’ Parkinsonian tremor: a potential pre-motor biomarker?

Williams, S., Fang, H., Alty, J., Qahwaji, Rami S.R., Patel, P., Graham, C.D. 21 September 2018 (has links)
no / There are a wide variety of ways to objectively detect neurological signs, but these either require special hard-ware (such as wearable technology) or patient behaviour change (such as engagement with smartphone tasks) [2]. Neither constraint applies to the technology of computer vision, which is the processing of single or multiple camera images by computer to automatically derive useful information. The only equipment involved is ubiquitous: camera and computer.We report a computer vision-enhanced video sequence from a 68-year-old man, diagnosed with idiopathic Parkinson’s disease 2 years previously.
2

Design and Implementation of an AR Application for Road Blueprint Visualization

Kanchi Reddy Gari, Obi Reddy, Vadde, Nithin Krishna January 2023 (has links)
This project uses Augmented Reality (AR) technology with the Unity game engine to create a mobile application that helps in road blueprint visualization. Users can use their smartphone camera to add digital information to the road blueprint by mapping the physical environment. This study explores AR technology’s potential in the road blueprint visualization industry. The benefits of using AR technology include reduced costs and simpler implementation in road blueprint visualization. This research is significant because no previous studies have explored AR technology’s potential in this field. The study suggests that AR technology can improve the user’s experience in visualizing road blueprints, making them more realistic and dynamic.
3

Statisk deformationsmätning med fotobaserad skanning : Utförd med icke-professionella digitalkameror

Jonsson, Anna, Eriksson, Pernilla January 2019 (has links)
Till följd av den utveckling som skett hos digitalkameror och programvaror för bildbehandling de senaste åren har intresset för fotobaserad skanning (FBS) vuxit. I denna studie utvärderades FBS som ett alternativ till terrester laserskanning (TLS) för statisk deformationsmätning och relaterade till kavitationsskador på vattenturbinkolvar där volym och maxdjup mäts. En stor del av syftet var att det skulle göras med simpla förutsättningar så att metoden blir enkel att utföra och tillämpbar framförallt i industrimiljöer. Simulerade deformationer skapades på en bräda i trä med en plan omgivande yta och på en boll i kork för att också undersöka en välvd yta. Fotograferingen utfördes med icke-professionella kameror, en digitalkamera och en smartphonekamera. Objekten som undersöktes hade en matt textur, bilderna togs med stor övertäckning (80–100%) och ljusförhållandena var goda för att undvika skuggning och blänk i bilderna. Det som utvärderades i studien var hur många kodade markörer som bör användas som konnektionspunkter för att förbättra bildmatchningen, optimalt antal skalstockar för skalsättning och vilken kameramodell och självkalibreringsmodell som gav den lägsta mätosäkerheten. Bildmatchningen och skapandet av 3D modellerna utfördes i programvaran Agisoft Photoscan. Analysen av modellerna utfördes i programvarorna 3DReshaper och CloudCompare. Resultaten utvärderades mot en skannad referensmodell framtagen med en ROMER Absolute Arm som har möjlighet att uppvisa mätosäkerheter på hundradels mm och kunde därmed anses som “sant” värde i denna studie. Resultatet visade att de kodade markörerna inte var nödvändiga som konnektionspunkter för bildmatchningen. Det visade även att oavsett kamera, självkalibreringsmodell och antal skalstockar (4, 3 & 2) låg alla modeller under den tillåtna avvikelsen i volym och maxdjup som normen för kavitationsskador på vattenturbinkolvar föreskriver (IEC 60609-1, från Swedish Standards Institute). Normen anger att mätosäkerheten på metoden som används inte får överskrida ±15% från det sanna värdet. Den här metoden har här visat sig vara tillämpbar och kan ersätta TLS för dokumentation och avgjutning för uppmätning av statiska deformationer när kraven på en relativ mätosäkerhet är ±5% av det sanna värdet. / As a result of the development of digital cameras and image processing software in recent years, the interest in close-range photogrammetry (CRP) has grown. In this study, CRP was evaluated as an alternative method to terrestrial laser scanning (TLS) for static deformation measurements and it was related to cavitation damage on water turbine pistons where the volume and maximum depth is measured. A large part of the purpose of the study was that it should be done with simple conditions so that the method will be easy to carry out and applies especially in industrial environments. Simulated deformations were created on a wooden board with a flat surrounding surface, and on a ball made of cork. The shooting was done with non-professional cameras, a digital camera and a smartphone camera. The objects that was examined had a matte texture, the images were taken with a large overlap (80–100%) and the lighting conditions were good enough to avoid shading and glare in the pictures. What was evaluated in the study was how many coded markers that should be used to improve image alignment, what the optimal number of scale bars for scaling the model is, and which camera model and self-calibration model that gave the lowest measurement uncertainty. The alignment of the images and creation of the 3D-models of the deformations were performed in the software Agisoft Photoscan. The analysis of the models was performed in the softwares 3DReshaper and CloudCompare. The results were evaluated against a scanned reference model developed with a ROMER Absolute Arm which has the ability to display measurement uncertainties on hundreds of millimetres and could thus be considered as a “true” value in this study. The result showed that the coded markers were not necessary in the image alignment procedure. It also showed that, regardless of which camera, self- calibration model and number of scale bars (4, 3 & 2), all the models created were below the permitted deviation in volume and maximum depth as the standard for cavitation damage on water turbine pistons (IEC 60609-1, from the Swedish Standards Institute) prescribes. The standard states that the measurement uncertainty of the method used must not exceed ±15% from the true value. This method has been found to be applicable and can replace TLS for documentation and volume measurement with a temporary filler for static deformations when the requirements for a relative measurement uncertainty are ±5% from the true value.
4

Volymberäkning från punktmoln skapatgenom Structure from Motion medbildunderlag från mobilkamera

Sigurdsson, Andreas, Lehr, Amadeus January 2021 (has links)
Tekniken hos mobiler och utvecklingen av programvaror för digitalafotogrammetriska tjänster har haft en snabb utveckling, vilket har gjort detmöjligt att enkelt kunna skapa 3D-modeller.Syftet med denna studie är att undersöka om det är möjligt att med hjälp avbildunderlag från en mobiltelefon kunna volymberäkna objekt så som t.ex.grushögar och diken. Den teknik som används är en automatiskbildjusteringsalgoritm som heter Structure from Motion (SfM). Från en seriedigitalafoton, som täcker objektet från olika vinklar och djup kan SfMidentifiera gemensamma punkter i fotona och sammanfläta dessa till ettpunkmoln som kan användas för att skapa en 3D-modell. Utifrån 3Dmodellen kan sedan en volymbestämning ske från mjukvaran AgisoftMetashape.Denna studie utför ett flertal olika tester för att utvärdera Structure fromMotion med bildunderlag från mobiltelefon för volymberäkning. Vissa objekthar att filmats med olika typer av telefoner och sedan jämförts mot terresterlaserskanning (TLS) som är en vanlig metod vid insamling av data förvolymberäkning. Volymberäkningarna har gjorts för både positiva ochnegativa volymer. Metoden har enbart använt sig av referensmått frånmåttband ute i fält. Detta gör att ingen avancerad mätutrustning har använts.Ett ljustest genomfördes för att se hur olika ljusförhållanden viddatainsamlandet kan påverka databearbetningen och volymberäkningen.Genom att beräkna skillnader i volym mellan 3D-modellerna kommer ettresultat tas fram.Resultaten från de 3D-modeller som skapats med dataunderlag från SfM gervolymskillnader i jämförelsen mot terrester laserskanning mellan 2,2% och6,8%. Dessa resultat är från en mur och ett dike som användes i studien,skillnaden motsvarar 0,031 m3 och 15,086 m3. Den negativa volym somberäknades, dvs. diket, är det objekt som ger störst avvikelse i volym, delsmellan de olika mobiltelefonerna, dels jämfört med TLS. Metoden ger enindikation på att det finns en stor möjlighet att kunna effektivisera processenför volymbestämning då metoden inte kräver speciella mätverktyg ellersärskilda förkunskaper vilket kan både spara tid och pengar. / The technology of smartphones and the development of software for digitalphotogrammetric services have developed rapidly, which has made it possibleto easily create 3D models.The purpose of this study is to investigate whether it is possible with the helpof image data from a mobile phone to be able to calculate the volume ofobjects such as e.g. gravel piles and ditches. The technology used is anautomatic image adjustment algorithm called Structure from Motion (SfM).From a series of digital photos, which cover the object from different anglesand depths, SfM can identify common points in the photos and intertwinethese into a point cloud that can be used to create a 3D model. Based on the3D model, a volume determination can then be made from the AgisoftMetashape software.This study performed a number of different tests to evaluate Structure fromMotion with image data from a smartphone for volume calculation. Someobjects have been filmed with different types of phones and then compared toterrestrial laser scanning (TLS) which is a common method of collecting datafor volume calculation. The volume calculations have been made for bothpositive and negative volumes. The method has only used referencemeasurements from measuring tapes in the field. This means that no advancedmeasuring equipment has been used. A light test was performed to see howdifferent light conditions during the data collection can affect the dataprocessing and volume calculation. By calculating differences in volumebetween the 3D models, a result will be produced.The results from 3D modeling created with data from SfM give a volumedifferences in the comparison with terrestrial laser scanning between 2.2%and 6.8%. These results are from a small stone wall and a ditch used in thestudy, the difference corresponds to 0.031 m3and 15.086 m3. The negativevolume that was calculated, ie. the ditch, is the object that gives the largestdeviation in volume, partly between the different mobile phones, partlycompared to TLS. The method gives an indication that there is a greatopportunity to be able to streamline the work process for volume calculationas the method does not require special measurement tools or special priorknowledge which can save both time and money.
5

Guidelines for smartphone usage in telemedical photography / Riktlinjer för användning av smartphones inom telemedicinsk fotografering

Hagman, Anna, Riedberg, Sander January 2014 (has links)
The wide usage of smartphones makes them an interesting and potential medical device. Given that smartphone cameras have a sufficiently high quality - some of the medical photography done at health care facilities could be done telemedically and by non-medically educated per- sons. Therefore a research of the quality of the photos taken with smartphone cameras has been done. This thesis presents guidelines regarding how inexperienced persons could take high qualitative medical photos with a smartphone. This thesis includes a review of current guidelines within medical photography. A compari- son between two popular smartphones and a professional medical camera has been done - where possibilities and limitations in smartphone cameras have been identified. In order to evaluate the sharpness and the color temperature representation in the photos taken with smartphones, an experiment with realistic lighting and easy accessible color-calibration cards has been done. The execution and the achieved result have formed the basis of the proposed guidelines. The result shows that smartphone cameras are of high quality and thereby could be used as a complement to advanced medical camera equipment. With the help of the proposed guidelines inexperienced persons could acquire sufficiently good medical photos, in order to be used as diagnostic material. This thesis provides a foundation for further research and implementation within the area, with the purpose of becoming an important part of the efficiency improvement within the telemedical health care.

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