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At least 37 records · Page 2Linked to original sources
PubMed2026

Clinical accuracy and short-term outcomes of intraoral photogrammetry for complete-arch implant rehabilitation: A retrospective multicentre study on 35 patients.

OBJECTIVES: To evaluate the clinical accuracy and short-term outcomes of complete-arch implant-supported fixed dental prostheses (ISFDPs) fabricated using an intraoral photogrammetry (IPG) based digital workflow in completely edentulous patients. METHODS: This multicenter retrospective clinical study included 35 patients rehabilitated with 52 complete-arch ISFDPs (10 FP1, 18 FP2 and 24 FP3 restorations) supported by 221 implants. All definitive prostheses were designed and fabricated using a fully digital workflow initiated by IPG acquisition with the Aoralscan Elite IPG® (SHINING 3D). The primary outcome was clinical accuracy, assessed at definitive prosthesis delivery through evaluation of passive fit using the Sheffield test and radiographic verification. Secondary outcomes included biologic and prosthetic complications, as well as implant and prosthesis survival rates during the follow-up. RESULTS: Passive fit was achieved in all definitive restorations (100%). Radiographic evaluation confirmed accurate marginal adaptation at the implant-prosthesis interface in all cases. No statistically significant differences in clinical accuracy were observed according to treated arch, number of supporting implants, or prosthetic design (P > .05). During a mean follow-up period of 12.1 ± 3.5 months, biologic and prosthetic complications were limited and generally minor. Implant survival was 99.5%, and prosthesis survival was 100%. CONCLUSIONS: Within the limitations of this retrospective clinical study, the IPG based workflow demonstrated high clinical accuracy and predictable short-term outcomes for complete-arch implant rehabilitation, consistently enabling passive fit and favorable prosthetic performance. CLINICAL RELEVANCE: IPG may represent a clinically reliable and predictable approach for complete-arch digital implant impression acquisition. The high rates of passive fit, together with the low incidence of biologic and prosthetic complications observed in this multicenter clinical study, support the use of IPG based workflows for the fabrication of complete-arch ISFDPs.

Humans↗
PubMed1994

Photogrammetry for documentation of vehicle deformations--a tool in a system for advanced accident data collection.

Vehicle deformations are important sources for information about the performance of safety systems. Photogrammetry has developed vastly under recent years. In this study modern photogrammetrical methods have been used for vehicle deformation analysis. The study describes the equipment for documentation and recording in the field (semi-metric camera), and a system for photogrammetrical measurements of the images in laboratory environment (personal computer and digitizing tablet). The material used is approximately 500 collected and measured cases. The study shows that the reliability is high and that accuracies around 15mm can be achieved even if the equipment and routines used are relatively simple. The effects of further development using video cameras for data capture and digital images for measurements are discussed.

Accidents, Traffic↗
PubMed1981

Telecentric photogrammetry: its development, testing, and application.

The development, testing, and application of a simple method of photogrammetry are outlined. Two phases of development are described, the first leading to the production of a frontal facial photograph with superimposed contour lines at 2 mm. intervals and the second leading to a frontal view together with right and left profile views of the patient. The choice of method used will naturally depend upon the purpose for which the clinician wishes to have a photogrammetric record of his patient. The root mean square error of the method is 0.33 mm.

Face↗
PubMed1985

Photogrammetry used to assess post-operative facial swelling in a drug trial.

A trial was designed to test the efficacy of ibuprofen in controlling post-operative pain and swelling following the surgical removal of lower third molar teeth. Because of the rigid criteria imposed on the trial it was not satisfactorily completed but the method of measuring the volume of the swelling by stereometric photogrammetry, which is reproducible, versatile and non-invasive, was considered to be worth reporting in context.

Adolescent↗
PubMed1992

Close range photogrammetry--a clinical dental research tool.

Photogrammetry is the art, science and technology of obtaining reliable information about physical objects through processes of recording and interpreting photographic images. This review outlines the principles of the technique and summarizes the various methodologies and applications in clinical dental research.

Dentistry↗
PubMed2000

Bioprosthetic heart valve leaflet motion monitored by dual camera stereo photogrammetry.

Dual camera stereo photogrammetry (DCSP) was applied to investigate the leaflet motion of bioprosthetic heart valves (BHVs) in a physiologic pulse flow loop (PFL). A 25-mm bovine pericardial valve was installed in the aortic valve position of the PFL, which was operated at a pulse rate of 70 beats/min and a cardiac output of 5 l/min. The systolic/diastolic aortic pressure was maintained at 120/80 mmHg to mimic the physiologic load experienced by the aortic valve. The leaflet of the test valve was marked with 80 India ink dots to form a fan-shaped matrix. From the acquired image sequences, 3-D coordinates of the marker matrix were derived and hence the surface contour, local mean and Gaussian curvatures at each opening and closing phase during one cardiac cycle were reconstructed. It is generally believed that the long-term failure rate of BHV is related to the uneven distribution of mechanical stresses occurring in the leaflet material during opening and closing. Unfortunately, a quantitative analysis of the leaflet motion under physiological conditions has not been reported. The newly developed technique permits frame-by-frame mapping of the leaflet surface, which is essential for dynamic analysis of stress-strain behavior in BHV.

Algorithms↗
PubMed2003

'Morphological imprint': determination of the injury-causing weapon from the wound morphology using forensic 3D/CAD-supported photogrammetry.

Forensic three-dimensional/computer aided design (CAD)-supported photogrammetry (FPHG) plays an important role in the field of the documentation of forensic relevant injuries; particularly so when a detailed, 3D reconstruction is necessary. This is demonstrated in the case of a patterned blunt injury to the face of a victim, which injury was subsequently proven by FPHG to have been caused by a blow from the muzzle of a soft air gun. The objects to be evaluated had to be series photographed in order to be evaluated virtually on the computer. These photo series were then analyzed with the RolleiMetric system. This system measures and calculates the spatial location of distinctive points on the objects' surfaces, and creates 3D data models of the objects. In a 3D/CAD program, the "virtual 3D model of the injury" is then compared against the "virtual 3D model of the possible injury-causing instrument". The validation of FPHG, as shown by the 3D match between certain characteristics of the muzzle form and the facial injury, demonstrates how this 3D method can be used for patterned wound documentation and analysis.

Adult↗
PubMed2003

Bite mark documentation and analysis: the forensic 3D/CAD supported photogrammetry approach.

Bite mark identification is based on the individuality of a dentition, which is used to match a bite mark to a suspected perpetrator. This matching is based on a tooth-by-tooth and arch-to-arch comparison utilising parameters of size, shape and alignment. The most common method used to analyse bite mark are carried out in 2D space. That means that the 3D information is preserved only two dimensionally with distortions. This paper presents a new 3D documentation, analysis and visualisation approach based on forensic 3D/CAD supported photogrammetry (FPHG) and the use of a 3D surface scanner. Our photogrammetric approach and the used visualisation method is, to the best to our knowledge, the first 3D approach for bite mark analysis in an actual case. The documentation has no distortion artifacts as can be found with standard photography. All the data are documented with a metric 3D measurement, orientation and subsequent analysis in 3D space. Beside the metrical analysis between bite mark and cast, it is possible using our method to utilise the topographical 3D feature of each individual tooth. This means that the 3D features of the biting surfaces and edges of each teeth are respected which is--as shown in our case--very important especially in the front teeth which have the first contact to the skin. Based upon the 3D detailed representation of the cast with the 3D topographic characteristics of the teeth, the interaction with the 3D documented skin can be visualised and analysed on the computer screen.

Bites, Human↗
PubMed2006

Anthropometric precision and accuracy of digital three-dimensional photogrammetry: comparing the Genex and 3dMD imaging systems with one another and with direct anthropometry.

A variety of commercially available three-dimensional (3D) surface imaging systems are currently in use by craniofacial specialists. Little is known, however, about how measurement data generated from alternative 3D systems compare, specifically in terms of accuracy and precision. The purpose of this study was to compare anthropometric measurements obtained by way of two different digital 3D photogrammetry systems (Genex and 3dMD) as well as direct anthropometry and to evaluate intraobserver precision across these three methods. On a sample of 18 mannequin heads, 12 linear distances were measured twice by each method. A two-factor repeated measures analysis of variance was used to test simultaneously for mean differences in precision across methods. Additional descriptive statistics (e.g., technical error of measurement [TEM]) were used to quantify measurement error magnitude. Statistically significant (P < 0.05) mean differences were observed across methods for nine anthropometric variables; however, the magnitude of these differences was consistently at the submillimeter level. No significant differences were noted for precision. Moreover, the magnitude of imprecision was determined to be very small, with TEM scores well under 1 mm, and intraclass correlation coefficients ranging from 0.98 to 1. Results indicate that overall mean differences across these three methods were small enough to be of little practical importance. In terms of intraobserver precision, all methods fared equally well. This study is the first attempt to simultaneously compare 3D surface imaging systems directly with one another and with traditional anthropometry. Results suggest that craniofacial surface data obtained by way of alternative 3D photogrammetric systems can be combined or compared statistically.

Anthropometry↗
PubMed1995

PAR Corneal Topography System (PAR CTS): the clinical application of close-range photogrammetry.

The PAR Corneal Topography System (CTS) is a computer-driven corneal imaging system which uses close-range photogrammetry (rasterphotogrammetry) to measure and produce a topographic map of the corneal surface. The PAR CTS makes direct point-by-point measurements of surface elevation using a stereo-triangulation technique. The CTS uses a grid pattern composed of horizontal and vertical lines spaced about 0.2 mm (200 microns) apart. Each grid intersection comprises a surface feature which can be located in multiple images and used to generate an (x,y,z) coordinate. Unlike placido disc-based videokeratoscopes, the PAR CTS requires neither a smooth reflective surface nor precise spatial alignment for accurate imaging. In addition to surface elevation, the PAR CTS computes axial and tangential curvatures and refractive power. Difference maps are available in all curvatures, refractive power, and in absolute elevation.

Cornea↗
PubMed1975

Determination of the principal distance and the location of the perspective centre in low magnification SEM photogrammetry.

The principal distance, D, from the centre of perspective in the SEM optical projection to the tilt axis of the specimen stage must be accurately determined before photogrammetric evaluation of stereoscopic pairs of micrographs can proceed. A precise procedure for measuring D is described in which the specimen stage X micrometer is used to measure the width of the field scanned for a particular width of the CRT, when the specimen stage is moved along the electron beam axis by amounts measured with the stage Z micrometer. The Z micrometer is calibrated with an external dial gauge. A plot of field width against Z extrapolated to zero gives the location of the perspective centre. In SEM photogrammetry, it is usual to leave the lens currents unchanged whilst recording the stereo-pairs. The values of D measured with a constant final lens current show that the perspective centre is located close to the final aperture in its conventional position. Previous determinations of D for Stereoscans have used a changing lens current to keep the specimen in focus at varying Z, and found a virtual centre several millimetres above the final aperture. The value of D so obtained should only be used if the micrographs were recorded with dynamic or automatic focusing systems.

Microscopy, Electron, Scanning↗
PubMed2002

Bioprosthetic heart valve leaflet deformation monitored by double-pulse stereo photogrammetry.

A double-pulse stereo photogrammetry technique has been developed for the dynamic assessment of the leaflet deformation of bioprosthetic heart valves under simulated physiological conditions. By using a specially designed triggering technique, which takes the advantage of the field transfer mechanisms of the charge coupled device camera, two consecutive images separated by a time interval as short as 5 ms were captured. This made it possible to investigate the realistic leaflet deformation during the valve opening and closing processes which typically last 25-45 ms. This technique was applied to assess a newly developed pericardial valve leaflet in a physiological pulse flow loop. Quantitative leaflet deformations of the valve opening and closing were generated from sequences of digital images. The results can later be applied to finite element analysis of bioprosthetic heart valve leaflet stress and strain during a complete cardiac cycle.

Algorithms↗
PubMed1999

Precise measurement of cat patellofemoral joint surface geometry with multistation digital photogrammetry.

Three-dimensional joint models are important tools for investigating mechanisms related to normal and pathological joints. Often these models necessitate accurate three-dimensional joint surface geometric data so that reliable model results can be obtained; however, in models based on small joints, this is often problematic due to limitations of the present techniques. These limitations include insufficient measurement precision the requirement of contact for the measurement process, and lack of entire joint description. This study presents a new non-contact method for precise determination of entire joint surfaces using multistation digital photogrammetry (MDPG) and is demonstrated by determining the cartilage and subchondral bone surfaces of the cat patellofemoral (PF) joint. The digital camera-lens setup was precisely calibrated using 16 photographs arranged to achieve highly convergent geometry to estimate interior and distortion parameters of the camera-lens setup. Subsequently, six photographs of each joint surface were then acquired for surface measurement. The digital images were directly imported to a computer and newly introduced semi-automatic computer algorithms were used to precisely determine the image coordinates. Finally, a rigorous mathematical procedure named the bundle adjustment was used to determine the three-dimensional coordinates of the joint surfaces and to estimate the precision of the coordinates. These estimations were validated by comparing the MDPG measurements of a cylinder and plane to an analytical model. The joint surfaces were successfully measured using the MDPG method with mean precision estimates in the least favorable coordinate direction being 10.3 microns for subchondral bone and 17.9 microns for cartilage. The difference in measurement precision for bone and cartilage primarily reflects differences in the translucent properties of the surfaces.

Algorithms↗
PubMed1980

Photogrammetry experiments with a model eye.

Digital photogrammetry was performed on stereophotographs of the optic nerve head of a modified Zeiss model eye in which optic cups of varying depths could be simulated. Experiments were undertaken to determine the impact of both photographic and ocular variables on the photogrammetric measurements of cup depth. The photogrammetric procedure tolerates refocusing, repositioning, and realignment as well as small variations in the geometric position of the camera. Progressive underestimation of cup depth was observed with increasing myopia, while progressive overestimation was noted with increasing hyperopia. High cylindrical errors at axis 90 degrees led to significant errors in cup depth estimates, while high cylindrical errors at axis 180 degrees did not materially affect the accuracy of the analysis. Finally, cup depths were seriously underestimated when the pupil diameter was less than 5.0 mm.

Astigmatism↗
PubMed1977

The use of photogrammetry in tissue compensator design. Part I: photogrammetric determination of patient topography.

The surface topography of a patient can be determined by photogrammetry before beginning radiotherapy. The source light of the therapy unit or simulator is used to project a grid pattern onto the patient, and this is then photographed together with control points consisting of miniature light bulbs mounted on a frame suspended from the wedge slot of the therapy machine. When the photograph is projected onto a graphics terminal for data entry into a computer, the three-dimensional topography of the patient's surface can be reconstructed as a two-dimensional matrix of discrete points. A computer algorithm can then design a tissue compensator to fit the individual patient.

Humans↗
PubMed2006

High-speed photogrammetry system for measuring the kinematics of insect wings.

We describe and characterize an experimental system to perform shape measurements on deformable objects using high-speed close-range photogrammetry. The eventual application is to extract the kinematics of several marked points on an insect wing during tethered and hovering flight. We investigate the performance of the system with a small number of views and determine an empirical relation between the mean pixel error of the optimization routine and the position error. Velocity and acceleration are calculated by numerical differencing, and their relation to the position errors is verified. For a field of view of approximately 40 mm x 40 mm, a rms accuracy of 30 mum in position, 150 mm/s in velocity, and 750 m/s2 in acceleration at 5000 frames/s is achieved. This accuracy is sufficient to measure the kinematics of hoverfly flight.

Animals↗
PubMed1981

[Stereophotography and photogrammetry of the physiological cup of the disc (author's transl)].

Researches related in this study were done on normal optic papillae. Their aim is to measure: a) the surface of the optic disc, the surface of the cup and the surface of the rim surrounding the cup; b) the depth of the cup; c) the diameters of the disc, the diameters of the cup and the width of the rim. Photographs were taken with a stereoscopic fundus camera and analysed by photogrammetry. There is a positive correlation between: a) the surface of the disc and the surface of the cup; b) the surface of the disc and the surface of the rim; c) the surface of the disc and the depth of the cup; d) the diameters of the disc and the diameters of the cup. There is no correlation between the diameter of the disc and the width of the rim. The ratio C/D is high when the disc is large.

Humans↗