METHOD AND SYSTEM FOR TRACKING ATTITUDE

A method and system for tracking attitude of a device includes fixing a two-dimensional array of photosensors to the device and using the array to form a reference frame and a sample frame of images. The fields of view of the sample and reference frames largely overlap, so that there are common imaged features from frame to frame. Sample frames are correlated with the reference frame to detect differences in location of the common features. Based upon detection of correlations of features, an attitudinal signal indicative of pitch, yaw, and/or roll is generated. In the preferred embodiment, the attitudinal signal is used to manipulate a screen cursor of a display system, such as a remote interactive video system (RIVS). However, attitudinal tracking using the invention may be employed in other applications. Another aspect of the invention is that the two-dimensional array is configured to compensate for any curvilinear distortions introduced by a lens system for imaging the features within the field of view of the array. A movable device, such as an optical mouse, includes a housing, a lens system in the housing and an array of photosensors in the housing for acquiring images in light applied to the array by the lens system, the array disposed in a plurality of rows and columns defining an optical axis, adjacent columns being spaced apart by boundaries having curvatures increasing with departure from the optical axis sufficient to compensate for curvilinear distortion introduced in the images by characteristics of the lens system, the array comparing data from the images to indicate motion of features of the images relative to the housing.