Computers and Electronics in Agriculture 50 (2006) 89–96 Laboratory measurement of seed drill seed spacing and velocity of fall of seeds using high-speed camera system D. Karayel a,∗ , M. Wiesehoff b , A. ¨ Ozmerzi a , J. M ¨ uller b a Akdeniz University, Faculty of Agriculture, Department of Agricultural Machinery, 07070 Antalya, Turkey b Hohenheim University, Institute for Agricultural Engineering in the Tropics and Subtropics, Stuttgart, Germany Received 31 August 2004; received in revised form 28 February 2005; accepted 17 May 2005 Abstract Due to the individual volumes of fluted wheel metering systems each holding more than one seed, seed drills provide random seed distribution. A prerequisite for the improvement of seed spacing is the fast and reliable evaluation of distribution accuracy in laboratory tests. A high-speed camera system for evaluating seed spacing uniformity and velocity of fall of seeds is described. The performance of the high-speed camera system in terms of seed spacing evaluation was compared with a sticky belt test stand, used as a reference. Identical seed patterns were evaluated applying both methods simultaneously using wheat and soybean seeds. The speed of the metering rollers of the seed drill was set at 10, 20, 30 and 40 rpm and that of the seed drill at a simulated travelling speed of 1 m/s. In general, the high-speed camera system worked well in obtaining the seed spacing and velocity of fall of seeds. In all the tests with the wheat and soybean seeds, the high-speed camera system did not miss any seed. The sowing uniformity of the seed drill as investigated was affected by the speed of the metering rollers. Coefficient of variation of seed spacing, velocity of fall and coefficient of variation of velocity of fall of seeds decreased as the speed of the metering rollers increased. © 2005 Elsevier B.V. All rights reserved. Keywords: High-speed camera; Seed drill; Sowing; Vision; Sticky belt 1. Introduction An important criterion in evaluating seed drill performance is seed spacing uniformity. A uniform distribution of seeds provides maximum space for each plant and increases yields due to the reduction of intra-specific competition (Heege, 1993). Also, weeds are suppressed due to the prevention of misses. The importance of this effect is proportional to the size of the required seed spacing, which is the reason precision drills have been developed for crops like maize or sugar beet. Precision drills are expensive and suitable only for large row spacings. The cereals are therefore usually sown by seed drills that provide a random distribution of the seeds due to the volumetric metering by fluted or studded rollers. There would be benefits from improving the uniformity of seed distribution such as increase in the yield of ∗ Corresponding author. E-mail address: dkarayel@akdeniz.edu.tr (D. Karayel). 0168-1699/$ – see front matter © 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.compag.2005.05.005