Influence of Television System Parameters and Imaging Geometry on the Accuracy of Fuel Assembly Head Height Difference Measurement Using the Parallax-Shift Method

Relevance. Non-contact monitoring of fuel assembly (FA) head height differences is important for ensuring the safe operation of nuclear power plants. Deviations in FA positions may indicate deformation of reactor core elements and affect reactor performance. The parallax-shift method, based on sequential frames acquired by a single television camera, eliminates mechanical contact with the monitored object and uses camera motion to form quasi-stereo pairs. However, its practical application requires assessing the influence of television system parameters and imaging geometry on measurement accuracy.

The purpose of this study is to establish relationships between television camera parameters, quasi-stereo pair geometry, and the error in determining FA head height differences using the parallax-shift method, as well as to identify rational parameter ranges for the measuring system.

Results. It was established that disparity estimation error is the dominant factor affecting final accuracy. Method stability is achieved through the coordinated selection of focal length, baseline, camera suspension height, and conditions for subpixel localization of fuel assembly head centers. Rational parameter ranges ensuring the required accuracy were determined. The novelty lies in the comprehensive assessment of the influence of television system parameters and imaging geometry on the accuracy of the parallax-shift method and in substantiating a rational quasi-stereo measurement configuration formed by a single television camera during arc motion.

Theoretical significance. The theoretical significance is determined by the development of a computational model of the parallax-shift method and by establishing relationships between disparity estimation error and relative height reconstruction error.

Practical significance. The obtained results can be used to configure television systems for FA monitoring and to justify requirements for non-contact measuring systems operating in the confined space of a reactor core.

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