APPARATUS FOR MEASURING VARIATION OF DIAMETER OF PLANT STEM

摘要

PURPOSE:To accurately measure a stem diameter even when the stem of an object to be measured is inclined by changing the relative angle of the axial direction of the stem of a plant and an irradiation light pattern by rotating the light emitting slit on the irradiation side of light and calculating the extreme value of an electric output signal proportional to the shade area of the stem. CONSTITUTION:The light from a miniature bulb electric source 1 is applied to a plant stem 9 to be measured as parallel light by a lens 6 through a slit 8 and a reflecting mirror 3. The slit 8 is rotated within a plane right-angled to the parallel light and parallel luminous flux having a rectangular cross-section applied to the plant stem 9 irradiates said stem while rotates within the plane right-angled to the advance direction of said luminous flux. When the parallel luminous flux having the rectangular cross-section becomes right-angled to the axial direction of the plant stem 9, the ratio of the luminous flux blocked by the plant stem 9 to the whole luminous flux becomes min. and the output of a photoelectric element 11 at this time corresponds to the diameter of the plant stem 9. Therefore, when the output of the photoelectric element 1 is reversely amplified, the signal proportional to the area of the shade of the stem is obtained.