Motion detection and analysis

An apparatus for determining movement, comprising means for generating at least two signals of different phase in dependence on the relative position of two objects, movement of said two objects causing corresponding changes in said at least two signals;

• and a processor for processing said at least two signals, thereby to determine said movement the processing by said processor is on the basis of locating the constellation states of successive values of the at least two signals in at least first and second co-ordinate axis systems, said at least first and second co-ordinate axis systems each defining at least three separate segments rotationally displaced, and said processor is arranged to monitor the change in said constellation states of the successive values by using at least two processed data samples, said successive samples being obtained by sampling said at least two signals at a predetermined clock rate.

A method of determining movement, comprising generating at least two signals of different phase in dependence on the relative position of two objects, movement of said two objects causing corresponding changes in said at least two signals;

• and processing said at least two signals, thereby to determine said movement, being on the basis of locating the constellation states of successive values of the at least two signals in at least one co-ordinate axis system, said at least one co-ordinate axis system defining at least six separate segments rotationally displaced, and said processing includes monitoring the change in said constellation states of the successive values by using at least two processed data samples, said successive samples being obtained by sampling said at least two signals at a predetermined clock rate.

A method of determining movement, comprising generating at least two signals of different phase in dependence on the relative position of two objects, movement of said two objects causing corresponding changes in said at least two signals;

• and processing said at least two signals, thereby to determine said movement, the processing being on the basis of locating the constellation states of successive values of the at least two signals in at least first and second co-ordinate axis systems, said at least first and second co-ordinate axis systems each defining at least three separate segments rotationally displaced, and said processing includes monitoring the change in said constellation states of the successive values by using at least two processed data samples, said successive samples being obtained by sampling said at least two signals at a predetermined clock rate.

An apparatus for determining movement, comprising:

• means for generating two signals of different phase in dependence on the relative position of two objects, the movement of said two objects producing corresponding changes in said two signals;
• a processor for processing said two signals, thereby to determine said movement whereby the means for processing is on the basis of locating successive values of constellation states of the two signals in a first co-ordinate axis system comprising an axis radiating from an origin, said processing means being arranged to monitor the change in said constellation states of the successive values by using at least a first and a second data samples which are obtained by sampling the two signals over time;
• wherein a second co-ordinate axis system comprising an axis radiating from an origin is provided whereby the second co-ordinate axis system is rotatable and prior to sampling the second data sample the second co-ordinate axis system is rotated relative to the first data sample such that the angular position of the first data sample with respect to the second co-ordinate axis system is known.