{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,25]],"date-time":"2026-02-25T00:16:49Z","timestamp":1771978609605,"version":"3.50.1"},"reference-count":32,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2021,3,20]],"date-time":"2021-03-20T00:00:00Z","timestamp":1616198400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/2.zoppoz.workers.dev:443\/https\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Bragato Research Institute (a subsidiary of New Zealand Winegrowers)","award":["Rod Bon\ufb01glioli Scholarship"],"award-info":[{"award-number":["Rod Bon\ufb01glioli Scholarship"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Grape yield estimation has traditionally been performed using manual techniques. However, these tend to be labour intensive and can be inaccurate. Computer vision techniques have therefore been developed for automated grape yield estimation. However, errors occur when grapes are occluded by leaves, other bunches, etc. Synthetic aperture radar has been investigated to allow imaging through leaves to detect occluded grapes. However, such equipment can be expensive. This paper investigates the potential for using ultrasound to image through leaves and identify occluded grapes. A highly directional low frequency ultrasonic array composed of ultrasonic air-coupled transducers and microphones is used to image grapes through leaves. A fan is used to help differentiate between ultrasonic reflections from grapes and leaves. Improved resolution and detail are achieved with chirp excitation waveforms and near-field focusing of the array. The overestimation in grape volume estimation using ultrasound reduced from 222% to 112% compared to the 3D scan obtained using photogrammetry or from 56% to 2.5% compared to a convex hull of this 3D scan. This also has the added benefit of producing more accurate canopy volume estimations which are important for common precision viticulture management processes such as variable rate applications.<\/jats:p>","DOI":"10.3390\/s21062182","type":"journal-article","created":{"date-parts":[[2021,3,21]],"date-time":"2021-03-21T23:47:41Z","timestamp":1616370461000},"page":"2182","update-policy":"https:\/\/2.zoppoz.workers.dev:443\/https\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Occluded Grape Cluster Detection and Vine Canopy Visualisation Using an Ultrasonic Phased Array"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/2.zoppoz.workers.dev:443\/https\/orcid.org\/0000-0001-8297-8472","authenticated-orcid":false,"given":"Baden","family":"Parr","sequence":"first","affiliation":[{"name":"Department of Mechanical and Electrical Engineering, Massey University, 229 Dairy Flat Highway, Auckland 0632, New Zealand"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/2.zoppoz.workers.dev:443\/https\/orcid.org\/0000-0002-1304-2483","authenticated-orcid":false,"given":"Mathew","family":"Legg","sequence":"additional","affiliation":[{"name":"Department of Mechanical and Electrical Engineering, Massey University, 229 Dairy Flat Highway, Auckland 0632, New Zealand"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Stuart","family":"Bradley","sequence":"additional","affiliation":[{"name":"Inverse Acoustics Ltd., 2 Rata Street, Auckland 0600, New Zealand"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/2.zoppoz.workers.dev:443\/https\/orcid.org\/0000-0002-2455-3131","authenticated-orcid":false,"given":"Fakhrul","family":"Alam","sequence":"additional","affiliation":[{"name":"Department of Mechanical and Electrical Engineering, Massey University, 229 Dairy Flat Highway, Auckland 0632, New Zealand"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,3,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"69","DOI":"10.2147\/IJWR.S69405","article-title":"Technology in precision viticulture: A state of the art review","volume":"7","author":"Matese","year":"2015","journal-title":"Int. J. Wine Res."},{"key":"ref_2","first-page":"11","article-title":"Managing variability in viticultural production","volume":"427","author":"Bramley","year":"1999","journal-title":"Grapegrow. Winemak."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Nuske, S., Achar, S., Bates, T., Narasimhan, S., and Singh, S. (2011, January 25\u201330). Yield estimation in vineyards by visual grape detection. Proceedings of the 2011 IEEE\/RSJ International Conference on Intelligent Robots and Systems (IROS), San Francisco, CA, USA.","DOI":"10.1109\/IROS.2011.6048830"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Nuske, S., Gupta, K., Narasimhan, S., and Singh, S. (2014). Modeling and calibrating visual yield estimates in vineyards. Field and Service Robotics, Springer.","DOI":"10.1007\/978-3-642-40686-7_23"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"79","DOI":"10.1016\/j.ifacol.2016.10.015","article-title":"Automated measurement of berry size in images","volume":"49","author":"Mirbod","year":"2016","journal-title":"IFAC-PapersOnLine"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1016\/j.compag.2014.10.003","article-title":"Vineyard yield estimation by automatic 3D bunch modelling in field conditions","volume":"110","year":"2015","journal-title":"Comput. Electron. Agric."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Dey, D., Mummert, L., and Sukthankar, R. (2012, January 9\u201311). Classification of plant structures from uncalibrated image sequences. Proceedings of the 2012 IEEE Workshop on Applications of Computer Vision (WACV), Breckenridge, CO, USA.","DOI":"10.1109\/WACV.2012.6163017"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Eccleston, K.W., Platt, I.G., and Tan, A.E.-C. (2018, January 6\u20137). SAR for grape bunch detection in vineyards. Proceedings of the Microwave Symposium (AMS), 2018, Brisbane, Australia.","DOI":"10.1109\/AUSMS.2018.8346953"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1287","DOI":"10.1016\/j.cropro.2006.11.003","article-title":"Variable rate application of plant protection products in vineyard using ultrasonic sensors","volume":"26","author":"Gil","year":"2007","journal-title":"Crop. Prot."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"239","DOI":"10.1016\/j.cropro.2009.12.022","article-title":"Variable rate dosing in precision viticulture: Use of electronic devices to improve application efficiency","volume":"29","author":"Llorens","year":"2010","journal-title":"Crop. Prot."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"636","DOI":"10.1007\/s11119-010-9186-1","article-title":"Integration of optical and analogue sensors for monitoring canopy health and vigour in precision viticulture","volume":"11","author":"Mazzetto","year":"2010","journal-title":"Precis. Agric."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"367","DOI":"10.13031\/2013.8587","article-title":"Investigation of laser and ultrasonic ranging sensors for measurements of citrus canopy volume","volume":"18","author":"Tumbo","year":"2002","journal-title":"Appl. Eng. Agric."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1377","DOI":"10.1109\/TIM.2007.900126","article-title":"Real-time tree-foliage surface estimation using a ground laser scanner","volume":"56","author":"Palacin","year":"2007","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"2177","DOI":"10.3390\/s110202177","article-title":"Ultrasonic and lidar sensors for electronic canopy characterization in vineyards: Advances to improve pesticide application methods","volume":"11","author":"Llorens","year":"2011","journal-title":"Sensors"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"108","DOI":"10.1016\/j.compag.2015.05.014","article-title":"Real time canopy density estimation using ultrasonic envelope signals in the orchard and vineyard","volume":"115","author":"Palleja","year":"2015","journal-title":"Comput. Electron. Agric."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1016\/j.compag.2017.01.012","article-title":"Real time canopy density validation using ultrasonic envelope signals and point quadrat analysis","volume":"134","author":"Palleja","year":"2017","journal-title":"Comput. Electron. Agric."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Kazys, R.J., Vilpisauskas, A., and Sestoke, J. (2018). Application of air-coupled ultrasonic arrays for excitation of a slow antisymmetric lamb wave. Sensors, 18.","DOI":"10.3390\/s18082636"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Allevato, G., Hinrichs, J., Rutsch, M., Adler, J., J\u00e4ger, A., Pesavento, M., and Kupnik, M. (2020). Real-time 3D imaging using an air-coupled ultrasonic phased-array. IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, IEEE.","DOI":"10.1109\/TUFFC.2020.3005292"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Legg, M., and Bradley, S. (2019). Ultrasonic arrays for remote sensing of pasture biomass. Remote Sens., 12.","DOI":"10.3390\/rs12010111"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Legg, M., and Bradley, S. (2019). Ultrasonic proximal sensing of pasture biomass. Remote Sens., 11.","DOI":"10.3390\/rs11202459"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"565","DOI":"10.1016\/S0041-624X(99)00168-7","article-title":"Characterization of air-coupled ultrasound transducers in the frequency range 40 kHz-2 MHz using light diffraction tomography","volume":"37","author":"Almqvist","year":"2000","journal-title":"Ultrasonics"},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Parr, B., Legg, M., Alam, F., and Bradley, S. (2020, January 9\u201311). Acoustic identification of grape clusters occluded by foliage. Proceedings of the Sensors and Applications Symposium (SAS 2020), Kuala Lumpur, Malaysia.","DOI":"10.1109\/SAS48726.2020.9220078"},{"key":"ref_23","unstructured":"(2021, March 20). DT9836 Series: High-Speed Simultaneous USB Devices with BNC. Available online: https:\/\/2.zoppoz.workers.dev:443\/https\/www.mccdaq.com\/Products\/Multifunction-DAQ\/DT9836."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"181","DOI":"10.1016\/S0041-624X(00)00059-7","article-title":"The use of broadband acoustic transducers and pulse-compression techniques for air-coupled ultrasonic imaging","volume":"39","author":"Gan","year":"2001","journal-title":"Ultrasonics"},{"key":"ref_25","unstructured":"ISO 9613-1:1993 (1993). Acoustics\u2014Attenuation of Sound During Propagation Outdoors\u2014Part 1: Calculation of the Absorption of Sound by the Atmosphere, International Organization for Standardization. Available online: https:\/\/2.zoppoz.workers.dev:443\/https\/www.iso.org\/standard\/17426.html."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"6058","DOI":"10.1109\/TIM.2020.2972657","article-title":"Correction method for magnitude and phase variations in acoustic arrays based on focused beamforming","volume":"69","author":"Yuan","year":"2020","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"2716","DOI":"10.1109\/TIM.2010.2040911","article-title":"A strict-time distributed architecture for digital beamforming of ultrasound signals","volume":"59","author":"Camacho","year":"2010","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"230","DOI":"10.1016\/j.apacoust.2013.08.008","article-title":"Automatic 3D scanning surface generation for microphone array acoustic imaging","volume":"76","author":"Legg","year":"2014","journal-title":"Appl. Acoust."},{"key":"ref_29","unstructured":"(2021, March 20). Oxford Reference: Speed of Sound. Available online: www.oxfordreference.com\/view\/10.1093\/oi\/authority.20110803100522606."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"3227","DOI":"10.1109\/TIM.2010.2047305","article-title":"Cross-correlation and sine-fitting techniques for high-resolution ultrasonic ranging","volume":"59","author":"Queiros","year":"2010","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_31","unstructured":"Proakis, J., and Manolakis, D. (1996). Digital Signal Processing: Principles, Algorithms, and Applications, Prentice-Hall International Inc.. [3rd ed.]."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Ximin, Z., Wanggen, W., Li, X., and Junxing, M. (2014, January 7\u20139). Mean shift clustering segmentation and ransac simplification of color point cloud. Proceedings of the 2014 International Conference on Audio, Language and Image Processing (ICALIP), Shanghai, China.","DOI":"10.1109\/ICALIP.2014.7009912"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/2.zoppoz.workers.dev:443\/https\/www.mdpi.com\/1424-8220\/21\/6\/2182\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T05:38:37Z","timestamp":1760161117000},"score":1,"resource":{"primary":{"URL":"https:\/\/2.zoppoz.workers.dev:443\/https\/www.mdpi.com\/1424-8220\/21\/6\/2182"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,3,20]]},"references-count":32,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2021,3]]}},"alternative-id":["s21062182"],"URL":"https:\/\/2.zoppoz.workers.dev:443\/https\/doi.org\/10.3390\/s21062182","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,3,20]]}}}