Reference marks recognition during automated sample positioning in probe microscopy

The article is devoted to automating the positioning of the scanning probe microscope into the marked zone using the reference marks. To recognize the reference marks, template matching was used. As a comparison measure, a cross-correlation function was used. A processing scheme has been developed that implies matching the reference marker template with the moving sample of the image and the search for singular points, which serves local maxima of the correlation function. The parameters changed during the multi-profile treatment process are defined. These parameters include the size of the search window for the search for local maxima of the correlation function and the threshold of filtering these maxima. It is described by the algorithm for changing the parameters of the correlation analysis when filtering the key points and determining their belonging to the reference marks. It is shown that the algorithm allowsto reduce the number of analysed image points by excluding points associated with the background elements of the image. It is proposed for analysing the ordering of the analysed points to use the combinations of their pairs of a certain length, as well as the magnitude of the mutual shift of the pairs and angle of rotation. The performance of the reduced solutions is confirmed on the images of the reference marks of two types - with a flat background and with a developed background relief of the reference marks.