Methods for providing for correcting data and associated apparatus
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.
1. A method for providing for correcting data from a sensor for changes in relative speed of the sensor when being moved with respect to a material being measured, the method comprising:
using 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 allowing for providing for correcting the data for changes in the relative speed of the sensor.
2. The method according to claim 1 , wherein the method comprises comparing the determined entropies, or the variation in determined entropies from one sample interval to a subsequent sample interval, to allow for providing for correcting the data for changes in the relative speed of the sensor.
3. The method according to claim 1 comprising determining the entropy from data associated with across a direction of travel of the sensor by using data provided from two or more sensor elements of the sensor, the two or more sensor elements being configured across the direction of travel.
4. The method according to claim 1 comprising determining the entropy from data associated with in the direction of travel of the sensor by using data provided from a particular sensor element of the sensor, with data from a corresponding sensor element, such as the same sensor element, but at a different sample interval.
5. The method according to claim 4 , wherein data from particular sensor elements is usable to reconstruct a pixel for an image.
6. The method according to claim 1 , comprising determining an anisotropy by comparing determined entropies to be different, the determined anisotropy usable to allow for providing for correcting the data.
7. The method according to claim 6 , wherein the determined anisotropy is indicative of the variation of speed of the sensor.
8. The method according to claim 6 , comprising determining an increase in relative speed of the sensor and a corresponding decrease in relative speed of the sensor by determining corresponding increases and decreases in determined anisotropies, in order to allow for correcting of the data for the increase and corresponding decrease in relative speed.
9. The method according to claim 8 comprising determining the corresponding increase and decrease in relative speed by comparing, with a threshold, the relative difference between corresponding determined anisotropies.
10. The method according to claim 1 , wherein the method is for correcting data from a logging tool.
11. A computer program, provided on a non-transitory computer readable medium, the computer program configured to provide the method of claim 1 .
12. Apparatus for providing for correcting data from a sensor for changes in relative speed of a sensor when being moved with respect to a material being measured, the apparatus configured to use a determined entropy from data associated with across a direction of travel of a sensor together with a determined entropy from data associated with in a direction a travel of a sensor, the determined entropies allowing for providing for correcting the data for changes in the relative speed of the sensor.
13. One or more measurement devices comprising one or more apparatus according to claim 12 .
14. The measurement device(s) according to claim 13 comprised with a logging tool.
15. A method for providing for correcting data from a measurement device comprising datasets from at least first and second sensors, such sensors being offset along the intended direction of travel of the measurement device, the method comprising:
comparing determined anisotropies in a first dataset associated with the first sensor with determined anisotropies in a second dataset associated with the second sensor, each determined anisotropy being associated with a determined entropy from data associated with across a direction of travel of a respective sensor together with a determined entropy from data associated with in a direction a travel of the respective sensor; and
using the compared anisotropies to allow for correcting the data from the measurement device.
16. The method according to claim 15 comprising providing for correcting the data in each dataset for speed variations when compared anisotropies associated with particular rows of data in the first and second datasets are determined to be similar or the same, or the variation of anisotropy is determined to be similar or the same, at, or around, the same time, such a row of data corresponding to data of a particular sample interval in each dataset associated with across a direction of travel.
17. The method according to claim 15 , wherein the compared anisotropies are used to allow for correcting the data for the offset between the first and second sensor when a compared variation of anisotropy in first and second datasets is determined to be similar, or the same, but at different times.
18. The method according to claim 15 , comprising using the compared anisotropies to allow for correcting the data from the measurement device, wherein the data has been previously corrected for the offset between first and second sensor, and wherein the method comprises re-correcting the data such that particular determined anisotropy occur at the same, or similar time.