Abstract: The method of this invention, and the apparatus which implements it, provides a way of sampling points on the surface of a portion of a rigid or semi-rigid object, which might be an anatomical body. Points are sampled by a moveable contact probe which emits a sonic waveform under the direction of a control unit. Multiple fixed sonic transducers in contact with the object at diverse locations detect the waveform, the arrival of which is timed for each transducer by the control unit. Given the speed of sound in the object and the coordinates of the transducers, a digital computer can compute the location of the probe. Two ways are presented to calibrate the locations of the transducers. Provision is made for mitigating possible distortion of soft object surfaces due to the contact force of the probe. During the sampling of probe contact locations, at least one physical or physiological attribute is also acquired.

Abstract: The method of this invention, and any apparatus which implements it, improves the accuracy of determining the sub-pixel location of the image of a point-like radiator of energy (typically light). This method distributes the image of a point radiator of energy over detector pixels such that the number of image pixels with high intensity gradients is maximized, while it minimizes the energy wasted on pixels with low intensity gradients, which contribute little to the computation of the sub-pixel location of the image. By improving such accuracy in each of one or more cameras, the accuracy of deriving the spatial location of the energy radiator improves also.