Estimation apparatus, estimation method and computer readable medium

An estimation method for estimating at least one of a position and an attitude of a second portion against a first portion in an apparatus comprising the first portion, the second portion, a movable mechanism which is configured to change at least one of a position and an attitude of the second portion against the first portion, at least one magnetic sensor which is provided in one of the first portion or the second portion, a magnet unit which is provided in the other of the first portion or the second portion and which is configured to provide a magnetic field which is measured by the at least one magnetic sensor, wherein the estimation method comprises:

• estimating a position or an attitude of the second portion against the first portion at a first time point, based on a measurement value at the first time point measured by the at least one magnetic sensor and reference information indicating measurement values of the at least one magnetic sensor in accordance with the position or the attitude of the second portion against the first portion;
• collecting a plurality of pieces of update information used for updating the reference information, which indicates measurement values in accordance with the position or the attitude of the second portion against the first portion which is measured by the at least one magnetic sensor while changing at least one of the position or the attitude of the second portion against the first portion over a predetermined movable range;
• performing clustering on the plurality of pieces of update information according to a predetermined classification condition;
• and
• updating the reference information based on at least one piece of update information included in a maximum class into which a highest number of pieces of information are classified among the plurality of pieces of update information.

A computer readable medium which is configured to store a program for causing a computer to function as an estimation apparatus which is configured to estimate at least one of a position and an attitude of a second portion against a first portion in an apparatus comprising the first portion, the second portion, a movable mechanism which is configured to change at least one of a position and an attitude of the second portion against the first portion, at least one magnetic sensor which is provided in one of the first portion or the second portion, a magnet unit which is provided in the other of the first portion or the second portion and which is configured to provide a magnetic field which is measured by the at least one magnetic sensor, wherein the computer readable medium configured to store the program causes the computer to perform:

• estimating a position or an attitude of the second portion against the first portion at a first time point, based on a measurement value at the first time point measured by the at least one magnetic sensor and reference information indicating measurement values of the at least one magnetic sensor in accordance with the position or the attitude of the second portion against the first portion;
• collecting a plurality of pieces of update information used for updating the reference information, which indicates measurement values in accordance with the position or the attitude of the second portion against the first portion which is measured by the at least one magnetic sensor while changing at least one of the position or the attitude of the second portion against the first portion over a predetermined movable range;
• performing clustering on the plurality of pieces of update information according to a predetermined classification condition;
• and
• updating the reference information based on at least one piece of update information included in a maximum class into which a highest number of pieces of information are classified among the plurality of pieces of update information.