Apparatus for making laminar radiograms

US4188640A · kind A · utility

Assignee

• U.S. Philips Corporation · US

Inventors

• Jurgen Dittrich · Schongau, DE
• Jurgen Heinzerling · Hamburg, DE
• Dietrich E. Meijer · Hamburg, DE
• Ralf Mollendorf · Bad Hersfeld, DE
• Friedrich Wolf · Planegg, DE

Key dates

• Filing date: Dec 21, 1977
• Grant date: Feb 12, 1980
• Expiry date: Dec 21, 1997

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N2223/419
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

In tomosynthesis, as is known, a series of individual images taken in different orientations, are superimposed. By shifting the individual images relative to each other the position of the layer which is sharply reproduced can be changed. However, there may still be unsharpness in said layer, in the case of image distortion during recording of the individual images, for example owing to the curvature of the input screen. This image distortion can hardly be compensated for, because it greatly depends on the projection angle. The invention provides a simple method of compensating for such image distortion. The image intensifier is then arranged and steered so that its optical axis is always parallel to the central ray. The distortion caused by the image intensifier curvature is then independent of the projection angle and can be eliminated in a comparatively simple manner. Steering the image intensifier in this way gives rise to additional distortion, because the planes, of which subsequently laminar radiograms are made by superposition, and the optical axis of the image intensifier are no longer perpendicular to each other. However, this is a simple geometric distortion which can be…