Abstract: Objects are dropped in succession through a viewing zone, where they are viewed in bright field illumination by three viewers along mutually orthogonal axes, using radiation of different wave-lengths (or viewing in rapid succession). The viewers sense the presented area. The presented areas are compared in a microprocessor in order to obtain a rough determination of the shape of the object. The presented areas can, for example, be summated to obtain a rough determination of the size of the object.

Abstract: The apparatus measures the transmission of light in successive falling objects. A beam is projected, wide enough to bathe all the facing surface of the object. An integrating sphere is on the other side of the object and its inlet and outlet apertures provide cut-offs so that only a hollow cone of flux scattered from the object is trapped in the integrating sphere, this flux being measured by a detector. The detector is connected to a micro-processor whose output is a measure of the clarity of the object. When the object is not in the beam, the beam falls on a detector so that the reduction in flux sensed by the detector is a measure of the projected area of the object. The micro-processor divides the signal from the detector by the reduction in flux, thereby making the output substantially independent of the size of the object.

Abstract: In order to color sort objects such as peas or sweets, they are dropped in succession through two integrating spheres. In the first sphere, the object absorbs infra-red radiation and the peak reduction in infra-red flux is detected in order to provide a signal responsive to the size of the object. In the second sphere, the object is illuminated with white light and the peak reduction in flux is detected by at least three detectors for three colors determined by filters. To make the illumination more uniform in the sphere, there is a step around the sphere almost half way down, with light sources equi-spaced around the step. The size signal is divided into the respective color signal in a micro-processor to produce a size-corrected color signal.