Method and photographic apparatus for performing motion studies on a moving subject. The moving subject is photographed through a rotating disc having at least one transparent aperture and a plurality of filter apertures covered with filter plates. Opaque regions of the disc separate the apertures from one another. Preferably, miniature spotlights are connected to moving points of the subject that are desired to be studied. Each of the spotlights projects a beam having essentially one selected wavelength to pass through the filter apertures and the filter plates. Incident background light, lighting the subject, is prevented from passing through the filter apertures by virtue of the filter plates. As a result, a photograph produced by the camera includes a series of light-streak images produced by the motion of the spotlights and the light emitted by the spotlights entering the filter apertures. Interruptions in the light-streaks are produced by the opaque regions of the disc. Additionally, the photograph also includes a series of stroboscopic images of the subject produced by the incident background light reflecting from the subject and entering the camera through the transparent aperture.
A system is provided for performing simultaneous bilateral measurements on a subject in motion at a test location. The system employs a plurality of observed targets attached to the moving subject, the targets being viewed simultaneously by each of two cameras disposed on opposite sides of the subject. Each of the cameras has associated therewith a light source emitting a light of a selected wavelength, the wavelengths for the two cameras being deliberately selected to be different enough to enable each camera to image the light source of the other without corruption of the observed data. The simultaneously operating two camera units may be computer controlled in preprogrammed manner or may be controlled by the operation of a manual control panel. In either case, the overall intensity of the two light sources providing illumination at the two selected different wavelengths facilitates the provision of illumination which avoids confusion by reflectance from the subject at other than the selected targets.
