Abstract: A displacement detection circuit (100) configured to implement a displacement detection method (500) for a pointing device (199) having at least one pixel array (190). The displacement detection circuit (100) includes at least one main calculator (110), at least one auxiliary calculator (111, 112, 113) at least one comparator (130) and at least one motion detector (150). The main calculator (110) is configured to calculate at least one main average (210) corresponding to the average of the at least one pixel array (190), which is compared to at least one auxiliary average (211, 212, 213) of the at least one auxiliary calculator (111, 112, 113). According to the result of the comparison, the at least one motion detector (150) indicates at least one direction (250) of displacement of the pointing device (199).

Abstract: A method for applying illumination correction for an optical computer mouse, includes: flashing a light source of the mouse directed towards a surface; accumulating voltage on a pixel array of the mouse to obtain raw pixel values of an image frame in response to detecting light reflected from the surface; applying analog correction to the raw pixel values based on digital gain coefficients to obtain an array of corrected pixel values forming corrected image data; digitizing the corrected image data with an analog-to-digital converter to obtain digital pixel values forming digital image data; and updating the digital gain coefficients so that a gain coefficient corresponding to a digital pixel value is incremented if the digital pixel value is below or equal to a given pixel threshold value, and so that the gain coefficient is decremented if the digital pixel value is above the given pixel threshold value.

Abstract: A displacement detection circuit (100) configured to implement a displacement detection method (500) for a pointing device (199) having at least one pixel array (190). The displacement detection circuit (100) includes at least one main calculator (110), at least one auxiliary calculator (111, 112, 113) at least one comparator (130) and at least one motion detector (150). The main calculator (110) is configured to calculate at least one main average (210) corresponding to the average of the at least one pixel array (190), which is compared to at least one auxiliary average (211, 212, 213) of the at least one auxiliary calculator (111, 112, 113). According to the result of the comparison, the at least one motion detector (150) indicates at least one direction (250) of displacement of the pointing device (199).

Abstract: A method of determining an absolute angle of a magnetic field includes receiving a first digital measurement value Bx of a first magnetic field component indicating intensity of the magnetic field along a first axis; receiving a second digital measurement value Bz of a second magnetic field component indicating the intensity of the magnetic field along a second axis, orthogonal to the first axis; determining absolute values for the first and second magnetic field components; and determining the angle of the magnetic field with respect to the first or second axis. The angle is determined so that the angle is derivable from the value of arcsin of Bz or of its approximation, when the absolute value of Bz? the absolute value of Bx, and derivable from the value of arccos of Bx or of its approximation, when the absolute value of Bz> the absolute value of Bx.

Abstract: A method of determining an absolute angle of a magnetic field includes receiving a first digital measurement value Bx of a first magnetic field component indicating intensity of the magnetic field along a first axis; receiving a second digital measurement value Bz of a second magnetic field component indicating the intensity of the magnetic field along a second axis, orthogonal to the first axis; determining absolute values for the first and second magnetic field components; and determining the angle of the magnetic field with respect to the first or second axis. The angle is determined so that the angle is derivable from the value of arcsin of Bz or of its approximation, when the absolute value of Bz? the absolute value of Bx, and derivable from the value of arccos of Bx or of its approximation, when the absolute value of Bz> the absolute value of Bx.