| CPC B24B 37/013 (2013.01) [G06N 3/084 (2013.01)] | 7 Claims |

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1. A polishing system, comprising:
a support to hold a polishing pad;
a carrier head to hold a surface of a substrate in contact with the polishing pad;
a motor to generate relative motion between the support and the carrier head;
an in-situ monitoring system to generate a signal comprising a sequence of raw signal values that depends on a thickness of a layer in a measurement spot on the substrate;
an in-situ imaging system to generate an image of at least the measurement spot of the substrate at substantially the same time as the in-situ monitoring system generates the signal for the measurement spot on the substrate; and
a controller configured to
receive the image from the in-situ imaging system,
receive the signal from the in-situ monitoring system,
determine a characterizing value relating to an orientation of the substrate in a portion of the image corresponding to the measurement spot by using machine vision processing of the image to generate the characterizing value,
perform a conversion of the sequence of raw signal values of the signal from the in-situ monitoring system into a sequence of thickness values for the measurement spot by providing the sequence of raw signal values and the characterizing value as input to a conversion algorithm wherein the characterizing value influences the conversion of the sequence of raw signal values to the sequence of thickness values, and wherein each thickness value of the sequence of thickness values represents a thickness of the layer in the measurement spot, and
at least one of halt polishing of the substrate or adjust a polishing parameter based on the thickness value.
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