AN AUTOMATED DIMENSION MEASUREMENT SYSTEM FOR SOFT BIOLOGICAL-MATERIALS

An automated system was developed to measure dimensions of soft or easily deformable biological and agricultural materials. An Instron universal testing machine controlled by a microcomputer was used as the measurement platform. Dimension measurement was based indirectly on the electrical conductivity of a specimen when contacted on opposing sides along the axis of measurement. The system consisted of two main subsystems: one to detect specimen contact and the other to determine the specimen dimension. A linear variable differential transformer was used to gauge the position of the crosshead of the testing machine before contact relative to a datum. Accuracy of the system as described was at worst ±0·5% when calibrated against specimens of 12·95, 15·42, and 17·15 mm as measured with machinists callipers. Comparative tests with a vernier height gauge showed no significant difference in height measurements of potato samples. © 1997 Elsevier Science Ltd. All rights reserved.