| 摘要 |
<p>PURPOSE: To enable precisely discriminating between polished and unhulled rice, between unhulled and unpolished glutinous rice, and between colored and unhulled rice by detecting light beams reflected from objects and transmitted through an optical filter that allows only a wavelength range absorbed by water to pass through it. CONSTITUTION: Near infrared rays including a wavelength range that is absorbed by water are applied to one or plural grains from a light source 1, and the reflected rays are transmitted through an optical filter 2 allowing only the wavelength range absorbed by water to pass through it, are then received by a photovoltaic cell 3 and converted into voltage signals corresponding to the quantity of the near infrared rays received, and these voltage values are compared with a predetermined threshold for the classification of the grains into unhulled and unpolished rice, and the mixing ratio of the unhulled rice is calculated. When the near infrared rays are applied to the grains from the light source 1 with the grains of unhulled and unpolished rice made to flow one by one and the reflected beams are received by the cell 3 through the filter 2 and converted into voltage signals, the voltage value of the unpolished rice is low and that of the unhulled rice high, so the unhulled rice can be distinguished from the unpolished rice when the threshold is set halfway between the voltage values.</p> |
