title: Fruit detectability analysis for different camera positions in sweet-pepper.
abstract: For robotic harvesting of sweet-pepper fruits in greenhouses a sensor system is required to detect and localize the fruits on the plants. Due to the complex structure of the plant, most fruits are (partially) occluded when an image is taken from one viewpoint only. In this research the effect of multiple camera positions and viewing angles on fruit visibility and detectability was investigated. A recording device was built which allowed to place the camera under different azimuth and zenith angles and to move the camera horizontally along the crop row. Fourteen camera positions were chosen and the fruit visibility in the recorded images was manually determined for each position. For images taken from one position only with the criterion of maximum 50% occlusion per fruit, the fruit detectability (FD) was in no case higher than 69%. The best single positions were the front views and looking with a zenith angle of 60° upwards. The FD increased when a combination was made of multiple viewpoint positions. With a combination of five favourite positions the maximum FD was 90%.
authors.affiliation: Wageningen UR Greenhouse Horticulture, P.O. Box 644, 6700 AP Wageningen, The Netherlands. jochen.hemming@wur.nl.
authors.forename: Jochen
authors.initials: J
authors.lastname: Hemming
authors.affiliation: Farm Technology Group, Wageningen University, P.O. Box 317, 6700 AH Wageningen, The Netherlands. josruizendaal@hotmail.com.
authors.forename: Jos
authors.initials: J
authors.lastname: Ruizendaal
authors.affiliation: Farm Technology Group, Wageningen University, P.O. Box 317, 6700 AH Wageningen, The Netherlands. janwillem.hofstee@wur.nl.
authors.forename: Jan Willem
authors.initials: JW
authors.lastname: Hofstee
authors.affiliation: Wageningen UR Greenhouse Horticulture, P.O. Box 644, 6700 AP Wageningen, The Netherlands. eldert.vanhenten@wur.nl.
authors.forename: Eldert J
authors.initials: EJ
authors.lastname: van Henten
mesh_terms: D002212:Capsicum / Q000033:anatomy & histology*; D018556:Crops, Agricultural / Q000033:anatomy & histology; D005638:Fruit / Q000033:anatomy & histology*; D007091:Image Processing, Computer-Assisted; D010781:Photography / Q000295:instrumentation*