{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,21]],"date-time":"2026-02-21T03:52:35Z","timestamp":1771645955035,"version":"3.50.1"},"reference-count":36,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2018,3,25]],"date-time":"2018-03-25T00:00:00Z","timestamp":1521936000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["Grant 31201135"],"award-info":[{"award-number":["Grant 31201135"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["31571568"],"award-info":[{"award-number":["31571568"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["51705365"],"award-info":[{"award-number":["51705365"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"name":"the Pearl River S&amp;T Nova Program of Guangzhou","award":["201506010081"],"award-info":[{"award-number":["201506010081"]}]},{"name":"\u201cClimbing\u201d Program of Guangdong","award":["Pdjh2018b0079"],"award-info":[{"award-number":["Pdjh2018b0079"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Night-time fruit-picking technology is important to picking robots. This paper proposes a method of night-time detection and picking-point positioning for green grape-picking robots to solve the difficult problem of green grape detection and picking in night-time conditions with artificial lighting systems. Taking a representative green grape named Centennial Seedless as the research object, daytime and night-time grape images were captured by a custom-designed visual system. Detection was conducted employing the following steps: (1) The RGB (red, green and blue). Color model was determined for night-time green grape detection through analysis of color features of grape images under daytime natural light and night-time artificial lighting. The R component of the RGB color model was rotated and the image resolution was compressed; (2) The improved Chan\u2013Vese (C\u2013V) level set model and morphological processing method were used to remove the background of the image, leaving out the grape fruit; (3) Based on the character of grape vertical suspension, combining the principle of the minimum circumscribed rectangle of fruit and the Hough straight line detection method, straight-line fitting for the fruit stem was conducted and the picking point was calculated using the stem with an angle of fitting line and vertical line less than 15\u00b0. The visual detection experiment results showed that the accuracy of grape fruit detection was 91.67% and the average running time of the proposed algorithm was 0.46 s. The picking-point calculation experiment results showed that the highest accuracy for the picking-point calculation was 92.5%, while the lowest was 80%. The results demonstrate that the proposed method of night-time green grape detection and picking-point calculation can provide technical support to the grape-picking robots.<\/jats:p>","DOI":"10.3390\/s18040969","type":"journal-article","created":{"date-parts":[[2018,3,26]],"date-time":"2018-03-26T03:43:29Z","timestamp":1522035809000},"page":"969","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":40,"title":["Green Grape Detection and Picking-Point Calculation in a Night-Time Natural Environment Using a Charge-Coupled Device (CCD) Vision Sensor with Artificial Illumination"],"prefix":"10.3390","volume":"18","author":[{"given":"Juntao","family":"Xiong","sequence":"first","affiliation":[{"name":"College of Mathematics and Informatics, South China Agricultural University, Guangzhou 510642, China"}]},{"given":"Zhen","family":"Liu","sequence":"additional","affiliation":[{"name":"College of Mathematics and Informatics, South China Agricultural University, Guangzhou 510642, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9553-4026","authenticated-orcid":false,"given":"Rui","family":"Lin","sequence":"additional","affiliation":[{"name":"College of Mathematics and Informatics, South China Agricultural University, Guangzhou 510642, China"}]},{"given":"Rongbin","family":"Bu","sequence":"additional","affiliation":[{"name":"College of Mathematics and Informatics, South China Agricultural University, Guangzhou 510642, China"}]},{"given":"Zhiliang","family":"He","sequence":"additional","affiliation":[{"name":"College of Mathematics and Informatics, South China Agricultural University, Guangzhou 510642, China"}]},{"given":"Zhengang","family":"Yang","sequence":"additional","affiliation":[{"name":"College of Mathematics and Informatics, South China Agricultural University, Guangzhou 510642, China"}]},{"given":"Cuixiao","family":"Liang","sequence":"additional","affiliation":[{"name":"College of Mathematics and Informatics, South China Agricultural University, Guangzhou 510642, China"}]}],"member":"1968","published-online":{"date-parts":[[2018,3,25]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"111","DOI":"10.1016\/j.compag.2014.04.011","article-title":"Stem localization of sweet-pepper plants using the support wire as a visual cue","volume":"105","author":"Bac","year":"2014","journal-title":"Comput. 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