Abstract: A method is provided for sensing displacement of an optical sensor relative to a surface, the sensor having at least first and second arrays with a plurality of photosensitive elements. The method involves: (i) generating for each array first set of quasi-sinusoidal signals at a first time and a second set of quasi-sinusoidal signals at a second time in response to motion of light received thereon; (ii) computing from said first and second sets of signals phase angle changes for signals received from each array; (iii) computing from said first and second sets of signals radius values for signals received from each array; (iv) computing unwrapped phase angle changes for signals received from each array; and (v) combining said unwrapped phase angle changes for each of said arrays using radius-weighted-averaging to provide a single weighted average of unwrapped phase angle change resulting from said motion of light.

Abstract: A circuit and method are provided for reducing power consumption in an optical navigation system for use in an input device to sense displacement of the device relative to a surface. Generally, the system includes: (i) an optical sensor having at least first and second arrays of photosensitive elements; (ii) imaging optics to map an illuminated portion of the surface to the optical sensor; (iii) a signal processor including a first and second sensor circuits coupled to the respective first and second arrays to generate from each array a set of signals in response to motion of light received thereon; and (iv) a control circuit capable of independently switching power to the sensor circuits. In one embodiment, the control circuit powers down one sensor circuit when the strength of the set of signals from the other is greater than a predetermined minimum thereby maintaining device performance. Other embodiments are also disclosed.

Abstract: A method is provided for determining motion of an optical sensor including a periodic photo-diode array relative to a surface. The method includes steps of (i) generating sets of quasi-sinusoidal signals responsive to motion along first and second directions; (ii) combining the sets of signals to generate a wrapped phase angle value for each direction at a first time; (iii) combining the sets of signals at a second time to generate a second wrapped phase angle value for each direction; (iv) computing wrapped phase angle changes for each direction between the first time and the second time; (v) computing velocity predictors for each direction using corrected average phase angle changes from a number of preceding successive frames; (vi) calculating the number of full 27? rotations needed to unwrap the phase angle changes for each direction using the velocity predictors; and (vii) computing the unwrapped or corrected phase angle changes.

Abstract: A signal processing circuit and processing method are provided for measuring an analog signal from a photo-detector. Generally, the method includes steps of: (i) sampling and storing a characteristic of the signal at a first predetermined time following a reset of the circuit; (ii) sampling the characteristic of the signal at a second predetermined time following a reset or initialization of the circuit; (iii) determining a difference between the stored characteristic of the signal sampled at the first predetermined time and the characteristic of the signal sampled at the second predetermined time; and (iv) converting the determined difference to a digital value and determining a slope of the signal from the digital value and the difference between the first and second predetermined times. Thus, the measurement of the slope is independent of and substantially unaffected by absolute values of the characteristics measured at the first and second predetermined times.

Abstract: A signal processor and method are provided for detecting movement of a surface relative to an optical sensor having an array of photosensitive elements.

Abstract: An automated gaming table tracking system for a gaming table, such as blackjack. A sensor located in the dealer's card playing area senses the start and end of each game. A unique player identity card is given to each player that contains information on the player. When a player arrives at a player position on the table, the player inserts his player identity card into a player station control at the player position. A central distribution control is connected to each player station control for determining the start and the end of each game and beginning and termination of play by each player at each position. A host computer of the present invention is then interconnected to the central distribution control for storing the player identity information and the player position for each player station control, the start and end of each of the games, and the beginning and termination of play at each player position from the central distribution control. The host computer prints a player tracking card.