Method and device for optically counting small particles
First Claim
1. In a method of optically counting small particles, like grains of seed and fertilizer employed in agriculture, wherein particles to be counted travel past a test field, interrupting as they do so a beam of light between a light emitter and a light detector, the improvement comprising providing the test field with an optical grid having a plurality of beams of light, detecting individual points where the path of a beam of light is interrupted by free-falling particles passing through the grid in sequential scanning cycles, retaining the detected interruptions for each cycle in the form of information describing one or more particles, comparing information describing the particles and obtained in different scanning cycles and deriving counting signals that correspond to the number of individual particles passing through the optical grid from the variations in the interruptions of the points determined during the comparison.
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Abstract
A method and device for optically counting small particles, like grains of seed and fertilizer and other materials employed in agriculture. The particles to be counted travel past a test field, interrupting as they do so a beam of light between a light emitter and a light detector. To make it possible to detect even several particles in the test field at the same time and to make the counting generally more precise, individual points where the path of a beam of light is interrupted by particles passing through the grid are detected in sequential scanning cycles by beams of light that create an optical grid and are retained in the form of information describing one or more particles, information describing the particles and obtained in different scanning cycles are compared, and counting signals that correspond to the number of individual particles passing through are derived from the variations in the interrupting points determined during the comparison.
30 Citations
14 Claims
- 1. In a method of optically counting small particles, like grains of seed and fertilizer employed in agriculture, wherein particles to be counted travel past a test field, interrupting as they do so a beam of light between a light emitter and a light detector, the improvement comprising providing the test field with an optical grid having a plurality of beams of light, detecting individual points where the path of a beam of light is interrupted by free-falling particles passing through the grid in sequential scanning cycles, retaining the detected interruptions for each cycle in the form of information describing one or more particles, comparing information describing the particles and obtained in different scanning cycles and deriving counting signals that correspond to the number of individual particles passing through the optical grid from the variations in the interruptions of the points determined during the comparison.
- 8. A device for optically counting small particles, like grains of seed and fertilizer employed in agriculture, comprising a test field including means forming an optical grid having beams of light through which free-falling particles to be counted pass, comprising light emitters and light detectors, wherein the light detectors are discrete photocells that produce output signals to individually indicate when the associated light beam has been interrupted, and a processor receptive of the output signals from the photocells for processing the output signals cyclically comprising means for detecting individual photocell outputs where the path of a beam of light is interrupted by particles passing through the grid in sequential scanning cycles, means for retaining the detected interruptions for each cycle in the form of information describing one or more particles, means for comparing information describing the particles and obtained in different scanning cycles and means for deriving counting signals that correspond to the number of individual particles passing through the optical grid from the variations in the interruptions of the points determined during the comparison.
Specification