Development of Measurement Device for Sugar Content of Sugar Beet by Near Infrared Spectroscopy with Ball Lens

Abstract

To establish a nondestructive method to measure the sugar content of a growing sugar beet root, we have developed a measurement device. The probe of the device, which emits and receives light, is brought in contact with the root area that is exposed above the soil surface, and the sugar content is estimated from the obtained near-infrared spectrum. To reduce measurement errors caused by the irregular surface shape and the very small size of the exposed root area, a ball lens is fitted on the probe tip and is then brought in contact with the root at the very small area. Our test results indicate that this device can measure the inside of the root up to a depth of 30mm and can reduce measurement errors.