Abstract: A pupil detection system projects two small infrared (IR) spots separated by approximately 0.5 mm. Each spot is turned on at different times (or alternatively, they can be modulated at different frequencies). The error signal produced by each spot is compared. If the errors are similar, a pupil is present. If the errors are different, no pupil is present (i.e., a blink or lost tracking). The sequencing of the IR spots and the reading of the detector data occur at the higher rates needed for accurate eye tracking.

Abstract: A fitness impairment tester implements a self-administered screening test to determine whether a subject is physically impaired. The tester is fully automated to respond to the entering of a subject's personal identification on a keypad. By superposing two different colored lights as viewed through an eyepiece, the subject aligns his or her pupil on the optical axis of pupil imaging optics which focuses an image of the subject's pupil on an image plane. The tester automatically recognizes this condition and audibly signals the subject that the test is about to begin. Light stimuli are provided to cause the pupil to change size and the eye to move. Pupil diameter measurements are made of the image of the subject's pupil in response to on axis light stimuli. Eye tracking of the subject's eye in response to moving light stimuli provide a measure of eye movements.

Abstract: A radio frequency transmission system contains at least one coherently modulated information signal, for example, a T.V. signal. At a transmission, the information signal is combined with two pilot tones, F1 and F2, related by the equation F1=N/M F2, where N and M are integers. The combined signal is suppressed-carrier modulated at microwave frequencies and transmitted to a receiver. At the receiver, the signals are demodulated by a local oscillator. The two pilot tones are then separated from the information signal and are compared to each other. The local oscillator frequency is controlled in response to this comparison such that the pilot tones at the receiver bear the same relationship to each other that they had at the transmitter. When this is achieved, the local oscillator frequency is the same as the suppressed-carrier frequency and co-channel interference is prevented.

Abstract: An intense electric field is employed as the external source of energy in carrying to a spectroscopic analysis of a chemical composition. The substance to be analyzed is placed between an insulated conductive electrode and a ground reference. A high voltage is then applied to the electrode to generate an electric field of a predetermined intensity within the test sample. As a result of the energy absorbed, the constituents of the sample are caused to release their characteristic spectral emissions. These emissions are optically filtered to isolate the wavelength of interest which is passed to a light detector and registered on a photon counting system. The procedure is especially and uniquely applicable for conducting an in situ chemical analysis of human sweat, thus offering a valuable aid in the diagnosis of various medical abnormalities.