[Image distortion in rotational panoramic radiography].
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Radiographic Image Enhancement↗
Biomedical subjects
G Tronje
Publications and source records attributed to G Tronje.
Image distortion in rotational panoramic radiography: V. Object morphology; inner structures.
A theoretic analysis of the distortion and displacement of the inner structures of three-dimensional objects in panoramic films has been performed. Mathematical calculations were carried out of the distortion of model structures simulating structural details in an object. Although the model structures are affected by the distortion effects inherent in rotational panoramic radiography, the panoramic film still gives a recognizable image of the inner structure of an object.
Humans↗
Image distortion in rotational panoramic radiography. VI. Distortion effects in sliding systems.
A mathematical model for calculating the form distortion in rotational panoramic radiographic systems with a sliding beam path and an elliptical form of the sharply depicted plane was developed. The distortion of a spherical model object was calculated for two different systems exemplifying properties of commercially available equipment. The spherical object was distorted toward an ovoid shape in the image. No marked deviations were found between this ovoid distortion and the ellipsoid distortion previously calculated for a theoretical system having a constant effective projection radius and a cylindrical form of the sharply depicted plane. Except for extremely displaced objects in the anterior region the form reproduction in sliding rotational panoramic systems seems to be satisfactory for clinical purposes.
Computers↗
Effects of errors in film speed and beam alignment on the image layer in rotational panoramic radiography.
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Models, Theoretical↗
Image distortion in rotational panoramic radiography. II. Vertical distances.
Films, exposed with rotational panoramic radiography, are generally considered inferior regarding the accuracy of measurements. Theoretic mathematical calculations, confirmed by an experimental test, have been performed in order to evaluate the reliability of measurements of distances that appear vertical in the image. It is demonstrated that, within certain limits, the panoramic film may be used for vertical measurements in clinical practice provided the patient has been properly positioned in the equipment during the exposure.
Mathematics↗
Image distortion in rotational panoramic radiography. III. Inclined objects.
Mathematical calculations have been performed to analyse how accurately the angle between objects, inclined in space, is reproduced on panoramic films. A marked tolerance against angle distortion was found. Angular measurements may be performed on correctly exposed panoramic films, and the values obtained are satisfactorily accurate for most clinical purposes.
Mathematics↗
Image distortion in rotational panoramic radiography. IV. Object morphology; outer contours.
On films exposed with rotational panoramic radiography, distortion effects are often apparent. The distortion of the outer contour of three-dimensional model objects jas been analysed mathematically. The applied mathematical expressions for coordinate transformation between object and film were confirmed experimentally. The distortion of the outer contour is dependent on the basic form of the object; the more rounded the object is, the less marked is the distortion. It is concluded that for practical clinical purposes the correctly exposed panoramic film is reliable when the form of rounded objects is assessed.
Mathematics↗
Image distortion in rotational panoramic radiography. I. General considerations.
The projection system in rotational panoramic radiography is complex in the respect that there are two projections of the object working simultaneously, one in the horizontal and one in the vertical dimension, giving rise to distortion of three-dimensional objects in the image. A mathematical method is presented for transforming data from three-dimensional objects to image data. This method may be used when analysing different distortion effects inherent in panoramic films.
Mathematics↗
Panoramic radiography of edentulous jaws. I. Frequency and distribution of pathological findings.
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Adult↗