An improved binocular localization method for apple based on fruit detection using deep learning

Apple picking robot is now being developed as an alternative to hand picking due to a great demand for labor during apple harvest season.Accurate detection and localization of target fruit is necessary for robotic apple picking.Detection accuracy has a great influence on localization results.Although current researches on detection and localization of apples using traditional image algorithms can obtain good results under laboratory conditions,it is difficult to accurately detect and locate objects in natural field with complex environments.With the rapid development of artificial intelligence,accuracy of apple detection based on deep learning has been significantly improved.Therefore,a deep learningbased method was developed to accurately detect and locate the position of fruit.For different localization methods,binocular localization is a widely used localization method for its bionic principle and lower equipment cost.Hence,this paper proposed an improved binocular localization method for apple based on fruit detection using deep learning.First,apples of binocular images were detected by Faster R-CNN.After that,a segmentation based on chromatic aberration and chromatic aberration ratio was applied to segment apple and background pixels in bounding box of detected fruit.Furthermore,template matching with parallel polar line constraint was used to match apples in left and right images.Finally,two feature points on apples were selected to directly calculate three dimensional coordinates of feature points with the binocular localization principle.In this study,Faster R-CNN achieved an AP of 88.12%with an average detection speed of 0.32 s for an image.Meanwhile,standard deviation and localization precision of depth of two feature points on each apple were calculated to evaluate localization.Results showed that the average standard deviation and the average localization precision of 76 groups of datasets were 0.51 cm and 99.64%,respectively.Results indicated that the proposed improved binocular localization method is promising for fruit localization。

Detection of abnormal hydroponic lettuce leaves based on image processing and machine learning

Accurate and fast detection of abnormal hydroponic lettuce leaves is primary technology for robotic sorting.Yellow and rotten leaves are main types of abnormal leaves in hydroponic lettuce.This study aims to demonstrate a feasibility of detecting yellow and rotten leaves of hydroponic lettuce by machine learning models,i.e.Multiple Linear Regression(MLR),K-Nearest Neighbor(KNN),and Support Vector Machine(SVM).One-way analysis of variance was applied to reduce RGB,HSV,and L*a*b*features number of hydroponic lettuce images.Image binarization,image mask,and image filling methods were employed to segment hydroponic lettuce from an image for models testing.Results showed that G,H,and a*were selected from RGB,HSV,and L*a*b*for training models.It took about 20.25 s to detect an image with 3024
4032 pixels by KNN,which was much longer than MLR(0.61 s)and SVM(1.98 s).MLR got detection accuracies of 89.48%and 99.29%for yellow and rotten leaves,respectively,while SVM reached 98.33%and 97.91%,respectively.SVM was more robust than MLR in detecting yellow and rotten leaves of hydroponic.Thus,it was possible for abnormal hydroponic lettuce leaves detection by machine learning methods.

A zero-sum game or an interactive frame?Iron competition between bacteriaand humans ininfectionwar

Iron is an essential trace element for both humans and bacteria.It plays a vital role in life,such as in redox reactions and electron transport.Strict regulatory mechanisms are necessary to maintain iron homeostasis because both excess and insufficient iron are harmful to life.Competition for iron is a war between humans and bacteria.To grow,reproduce,colonize,and successfully cause infection,pathogens have evolved various mechanisms for iron uptake from humans,principally Fe^(3+)-siderophore and Fe^(2+)-heme transport systems.Humans have many innate immune mechanisms that regulate the distribution of iron and inhibit bacterial iron uptake to help resist bacterial invasion and colonization.Meanwhile,researchers have invented detection test strips and coupled antibiotics with siderophores to create tools that take advantage of this battle for iron,to help eliminate pathogens.In this review,we summarize bacterial and human iron metabolism,competition for iron between humans and bacteria,siderophore sensors,antibiotics coupled with siderophores,and related phenomena.We also discuss how competition for iron can be used for diagnosis and treatment of infection inthefuture.