Abstract: The apparatus and methods allow for correcting data from a sensor due to changes in relative speed of that sensor. The methods and apparatus described use a determined entropy from data associated with across a direction of travel of the sensor together with a determined entropy from data associated with in a direction of travel of the sensor. The determined entropies allow for providing for correcting the data for changes in the relative speed of the sensor. Also, described are methods and apparatus for correcting data from at least first and second sensors of a measurement device, whereby features are correlated from datasets taken from both sensors to determine one or more corresponding signatures. These signatures can then be used to correct the data from first and second sensors.

Abstract: The apparatus and methods allow for correcting data from a sensor due to changes in relative speed of that sensor. The methods and apparatus described use a determined entropy from data associated with across a direction of travel of the sensor together with a determined entropy from data associated with in a direction of travel of the sensor. The determined entropies allow for providing for correcting the data for changes in the relative speed of the sensor. Also, described are methods and apparatus for correcting data from at least first and second sensors of a measurement device, whereby features are correlated from datasets taken from both sensors to determine one or more corresponding signatures. These signatures can then be used to correct the data from first and second sensors.