Image distortion determining method and device

Abstract

Using the method it is possible to determine distortions in an image (6) which can be produced by an imaging system from an object (2, 2*) arranged in the imaging space of the imaging system, wherein in the image (6) the first A region (8) is displayed undistorted, while a second region (10) of the imaging space is displayed distorted in the image (6). Wherein, an image with at least three markers (A, B, C, C*) can be generated by using the imaging system. The spatial positions of the marks relative to each other are known, wherein the first mark (A) and the second mark (B) of the three marks (A, B, C, C*) are arranged in the first area (8) , and a third marker (C, C*) of the three markers (A, B, C, C*) is arranged in the second area (10). Determine the position of the imaged markers (A, B, C', C", C"') in the image (6). The ideal position of the third mark (C, C*) is determined based on the known spatial position of the third mark (C, C*) relative to the first and second marks (A, B). A position difference (z, α) of the imaged third marker from its ideal position is determined, the position difference (z, α) representing a measure for the distortion.

Description

technical field [0001] The invention relates to a method and a measuring piece for determining image distortion. Background technique [0002] In all types of imaging methods, such as those using optics, x-rays, ultrasound, electron beams, magnetic resonance, etc., an image of an area of ​​the object to be examined is produced, the realism of the obtained image is comparable to that of the object under examination The comparison is a decisive quality criterion. As a rule, in all imaging systems that currently exist, the image fidelity is not ideal; rather, distortions occur in the imaging of the object to be examined depending on the displayed image area and the quality of the imaging system used. Thus, for example, distortions in magnetic resonance tomography (MRT) are caused by the fundamental magnetic field's contribution to the ideal value B 0 This results in position-dependent deviations and also position-dependent nonlinearities of the gradient system. Typically, th...

AI Technical Summary

Problems solved by technology

Although it is in principle possible to use a larger model, it is more expensive to manufacture, and when its diameter is larger than 300mm, it will be heavy and thus not easy to handle

Another disadvantage of this method is that the measurement of distortion can only be carried out by observing two distorted image points simultaneously in the radial direction

Therefore, only the average of the distortion of two image points can be measured and not a certain point

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