基于高光谱图像技术的油菜籽品种鉴别方法研究

提出了一种采用高光谱图像技术结合人工神经网络对油菜籽品种进行鉴别的方法.采集多个品种油菜籽400～1 000 nm范围的高光谱图像数据,通过主成分分析法(PCA)获得主成分图像,确定特征波长;采用基于灰度直方图和灰度共生矩阵联合的统计方法从特征图像中提取纹理特征参数,应用人工神经网络建立油菜籽品种鉴别模型.结果表明,模型训练时品种判别率为93.75%,预测的判别率为91.67%.说明高光谱图像技术对油菜籽品种具有较好的分类和鉴别作用.     

基于轮廓纹理特征和线性判别分析的鲜烟叶部位识别方法

为实现鲜烟叶采收部位的数字化识别,进一步提升采收鲜烟叶素质的一致性,利用轮廓纹理特征和线性判别分析（LDA）技术对不同着生部位鲜烟叶进行研究,首先,对采集的鲜烟叶图像进行图像缩放、灰度化、二值化等预处理操作,提取狭长度、矩形度等4个轮廓特征参数,进而提取鲜烟叶图像的灰度共生矩阵（GLCM）特征,并通过LDA进行特征降维,之后利用K近邻算法（KNN）对鲜烟叶部位进行分类。结果表明,所提取未经降维处理的轮廓纹理特征在不同分类模型中的识别准确率均达到0.80以上,可有效反映鲜烟叶部位特征。相对于主成分分析（PCA）处理和未经降维处理,采用LDA降维处理的模型识别准确率最高。所构建的基于KNN算法的鲜烟叶部位识别模型,其精确率、召回率、F1分数、准确率均达到0.99,能够较好地识别鲜烟叶着生部位。     

基于Adaboosting_SVM算法的多特征蛋壳裂纹识别

以无裂纹蛋和裂纹蛋为测试对象,采用机器视觉技术和支持向量机等技术手段,分析无裂纹蛋和裂纹蛋在图像上的差异,提取特征参数,实现蛋壳裂纹的自动识别;针对蛋壳表面的亮斑,对预处理后的图像运行消除亮斑算法并进行区域标记。在此基础上,从5个不同视角提取13个能够表征无裂纹蛋和裂纹蛋的特征参数,分别是图像标记区域参数(区域标记数和标记点数)、几何特征参数(长轴和短轴)、基于Freeman链码的形状参数(形状数)、纹理特征参数(均值、标准偏差、平滑度、三阶矩、一致性、熵)和频谱特性参数(最大幅值和最大相位)。采用Adaboosting算子对上述特征参数进行优化,突出影响因子较大的参数组合,作为SVM的输入向量,建立蛋壳裂纹的识别模型。结果表明:该方法对蛋壳表面的亮斑、微小裂纹及普通裂纹均具有识别能力,模型正确率达97.5%,符合蛋品企业对蛋壳裂纹检测的精度要求。     

基于机器视觉的鸭蛋裂纹自动检测

通过计算机视觉系统获取鸭蛋表面的图像,利用颜色特征参数和灰度阈值方法对图像进行分割.提取分割后的裂纹区域和噪声区域的6个几何特征参数,对图像进行识别,裂纹识别率为93.392%,噪声识别率为93.602%.     

基于光谱和Gabor纹理信息融合的油桃品种识别

为实现油桃品种的快速且无损鉴别,对油桃高光谱图像中的光谱和图像信息进行分析。在光谱信息提取中,采用偏最小二乘回归(partial least squares regression,简称PLSR)从全波段光谱数据提取9个特征波长。在图像信息获取中,采用主成分分析(principal component analysis,简称PCA)获得主成分图像,并提取主成分图像的Gabor纹理特征。分别建立基于特征波长光谱特征、主成分图像纹理特征和光谱纹理特征融合的最小二乘支持向量机(least squares support vector machine,简称LS-SVM)和极限学习机(extreme learning machine,简称ELM)油桃品种判别模型。结果表明,基于融合特征的LS-SVM和ELM模型识别率分别为94.7%、92.1%,较单独采用光谱信息和纹理信息的识别率都高,说明采用光谱信息和Gabor纹理信息融合的方法可以实现油桃品种判别,为农产品无损检测提供参考价值。     

基于分形维数的图像纹理分析

利用分数维能够把图像的空间信息和灰度信息有机结合起来的特性,提出了一种基于分形维数的图像纹理分析方法.为了更准确地描述纹理表面的粗糙度,该方法首先将纹理图像进行6种灰度变换并计算其相应的分形维数,同时采用H lder指数作为描述图像纹理的奇异性特征,然后利用提取的纹理特征对图像进行纹理分割.实验结果表明:采用该方法所分割的图像能很好地体现图像的纹理分布.     

基于Gabor滤波与Tamura纹理特征的板材分类研究

板材表面的纹理特征是木质板材表面最为直观的特性,同时也是建筑装潢质量和木制品品质的重要评价指标。以中国东北部常见的红松、落叶松、白桦、水曲柳和柞木等5种树种的弦切、径切图像作为研究对象,提出一种基于多通道Gabor滤波和Tamura纹理特征的板材纹理特征提取方法,克服了传统方法在提取样本图像的全局特征时对局部纹理特征不敏感的问题。具体是将基于视觉心理学的Tamura纹理特征与Gabor滤波器进行结合,在不同频率、不同方向上共24组滤波器的虚部卷积图像上进行纹理特征参数提取,结合上述的纹理特征参数在BP神经网络、KNN和支持向量机分类器上进行分类试验,最佳特征参数体系的识别率达97.8%。     

木材纹理的分形特征与计算

采用分形方法对20种典型的木材径向、弦向纹理图像进行了分析,结果表明:木材纹理的分形维数值能够很好地表征木材表面纹理的形状、分布密度、均匀程度和宽度特征,符合了木材表面纹理的粗糙性和复杂性规律.分形维数值本身是几个常规纹理特征的综合体,使得纹理特征的表达得以简化.分形方法为木材表面纹理的分布密度和复杂度等特征参数的定量化分析提供了一种新的思路和方法.     

基于 PCA 特征融合与 LDA 分类的实木地板纹理判别方法

纹理一致性影响着实木地板档次,针对目前实木地板纹理分类速度慢、精度低的问题,提出一种适合区分直纹、抛物纹、乱纹3类纹理的在线检测方法。方法首先对纹理图像进行缩小,运用视觉心理学的Tamura方法提取粗糙度、对比度、方向度、线性度、规整度、粗略度等6个纹理特征;同时在原图像提取反映图像全局信息的灰度均值、方差、熵等3个统计量;然后,运用主成分分析法（PcA）对3类纹理9个特征进行降维融合操作;最后,采用线性判别分析方法（LDA）构建3类纹理的辨识模型。采用200幅实木地板纹理图像进行实验,当主成分个数为7时,分类正确率稳定达到85％,较传统Tamura方法的83％和全局基本统计量的70％有所提高;特征提取时间为0．5548S,比缩小前图像的Tamura特征提取时间55．7000S明显减低,而分类正确率没有明显变化。     

基于PCA特征融合与LDA分类的实木地板纹理判别方法

纹理一致性影响着实木地板档次,针对目前实木地板纹理分类速度慢、精度低的问题,提出一种适合区分直纹、抛物纹、乱纹3类纹理的在线检测方法。方法首先对纹理图像进行缩小,运用视觉心理学的Tamura方法提取粗糙度、对比度、方向度、线性度、规整度、粗略度等6个纹理特征;同时在原图像提取反映图像全局信息的灰度均值、方差、熵等3个统计量;然后,运用主成分分析法(PCA)对3类纹理9个特征进行降维融合操作;最后,采用线性判别分析方法(LDA)构建3类纹理的辨识模型。采用200幅实木地板纹理图像进行实验,当主成分个数为7时,分类正确率稳定达到85%,较传统Tamura方法的83%和全局基本统计量的70%有所提高;特征提取时间为0.554 8 s,比缩小前图像的Tamura特征提取时间55.700 0 s明显减低,而分类正确率没有明显变化。     

Identification of nine Iranian wheat seed varieties by textural analysis with image processing

Applying machine vision techniques to classify wheat seeds based on their varieties is an objective method which can increase the accuracy of this process in real applications. In this study, several textural feature groups of seeds images were examined to evaluate their efficacy in identification of nine common Iranian wheat seed varieties. On the whole, 1080 gray scale images of bulk wheat seeds (120 images of each variety) were acquired at a stable illumination condition (florescent ring light). Totally, 131 textural features were extracted from gray level, GLCM (gray level cooccurrence matrix), GLRM (gray level run-length matrix), LBP (local binary patterns), LSP (local similarity patterns) and LSN (local similarity numbers) matrices. The so-called stepwise discrimination method was employed to select and rank the most significant textural features of each matrix individually as well as features of all matrices simultaneously. LDA (linear discriminate analysis) classifier was employed for classification using top selected features. The average classification accuracy of 98.15% was obtained when top 50 of all selected features were used in the classifier. The results confirmed that LSP, LSN and LBP features had a significant influence on the improvement of classification accuracy compared to previous studies.     

Effect of probability-distance based Markovian texture extraction on discrimination in biological imaging

The effect of probability-distance based re-weighting of image texture features on their discrimination ability was evaluated in this study. A quadratic surface smoothing function was developed from the Bhattacharyya probability distance between two classes of images. The function was used as a re-weighting function for standard grey level co-occurrence matrix (GLCM) textural features in two cases. Case 1 involved 42 images of health and smokers’ lungs. Case 2 involved 144 images of well watered; partially water stressed and dry Rhacomitrium canescens plants. Multilayer perception (MLP) neural networks (NN) classifiers based on standard weighted and probabilistic-distance based re-weighted GLCM textural features were developed for each case. The classifiers were trained and tested using the leave-one-out and the cross-validation evaluation strategies.Probability-distance based re-weighting of GLCM textural features resulted in 37% and 39.22% reduction in true classification error for cases 1 and 2, respectively. It was concluded that re-weighting image texture features based on the probability distance between the classes involved, makes the GLCM texture analysis technique more discriminative and adaptive. This modification will help to overcome the fixed nature of GLCM features which is an area of weakness open to further improvement. Although GLCM features were used in this study, the method can be extended to other co-occurrence-based methods.     

Mapping regional cropping patterns by using GF-1 WFV sensor data

The successful launched Gaofen satellite no. 1 wide field-of-view(GF-1 WFV) camera is characterized by its high spatial resolution and may provide some potential for regional crop mapping. This study,taking the Bei'an City,Northeast China as the study area,aims to investigate the potential of GF-1 WFV images for crop identification and explore how to fully use its spectral,textural and temporal information to improve classification accuracy. In doing so,an object-based and Random Forest(RF) algorithm was used for crop mapping. The results showed that classification based on an optimized single temporal GF-1 image can achieve an overall accuracy of about 83%,and the addition of textural features can improve the accuracy by 8.14%. Moreover,the multi-temporal GF-1 data can produce a classification map of crops with an overall accuracy of 93.08% and the introduction of textural variables into multi-temporal GF-1 data can only increase the accuracy by about 1%,which suggests the importance of temporal information of GF-1 for crop mapping in comparison with single temporal data. By comparing classification results of GF-1 data with different feature inputs,it is concluded that GF-1 WFV data in general can meet the mapping efficiency and accuracy requirements of regional crop. But given the unique spectral characteristics of the GF-1 WFV imagery,the use of textual and temporal information is needed to yield a satisfactory accuracy.     

Detection of Fusarium damaged kernels in Canada Western Red Spring wheat using visible/near-infrared hyperspectral imaging and principal component analysis

Fusarium damage in wheat reduces the quality and safety of food and feed products. In this study, the use of hyperspectral imaging was investigated to detect fusarium damaged kernels (FDK) in Canadian wheat samples. Eight hundred kernels of Canada Western Red Spring wheat were segregated into three classes of kernels: sound, mildly damaged and severely damaged. Singulated kernels were scanned with a hyperspectral imaging system in the visible-NIR (400-1000 nm) wavelength range. Principal component analysis (PCA) was performed on the images and the distribution of PCA scores within individual kernels measured to develop linear discriminant analysis (LDA) models for predicting the extent of fusarium damage. An LDA model classified the wheat kernels into sound and FDK categories with an overall accuracy of 92% or better. Classification based on six selected wavelengths was comparable to that based on the full-spectrum data.     

基于边缘检测的微小疲劳裂纹图像数据提取

根据高分辨率动态扫描电镜观察到疲劳裂纹的实际扩展过程图像的特点,结合图像处理的基本理论和方法,提出了适合于疲劳裂纹图像的二值化处理方法和基于小波疲劳裂纹图像边缘检测算法,对疲劳裂纹的瞬时扩展图像进行了数据提取。     

A new approach to aflatoxin detection in chili pepper by machine vision

Aflatoxins are the toxic metabolites of Aspergillus molds, especially by Aspergillus flavus and Aspergillus parasiticus. They have been studied extensively because of being associated with various chronic and acute diseases especially immunosuppression and cancer. Aflatoxin occurrence is influenced by certain environmental conditions such as drought seasons and agronomic practices. Chili pepper may also be contaminated by aflatoxins during harvesting, production and storage. Aflatoxin detection based on chemical methods is fairly accurate. However, they are time consuming, expensive and destructive. We use hyperspectral imaging as an alternative for detection of such contaminants in a rapid and nondestructive manner. In order to classify aflatoxin contaminated chili peppers from uncontaminated ones, a compact machine vision system based on hyperspectral imaging and machine learning is proposed. In this study, both UV and Halogen excitations are used. Energy values of individual spectral bands and also difference images of consecutive spectral bands were utilized as feature vectors. Another set of features were extracted from those features by applying quantization on the histogram of the images. Significant features were selected based on proposed method of hierarchical bottleneck backward elimination (HBBE), Guyon’s SVM-RFE, classical Fisher discrimination power and Principal Component Analysis (PCA). Multi layer perceptrons (MLPs) and linear discriminant analysis (LDA) were used as the classifiers. It was observed that with the proposed features and selection methods, robust and higher classification performance was achieved with fewer numbers of spectral bands enabling the design of simpler machine vision systems.     

斜拉索PE保护层表面伤痕检测算法设计

提出了一种检测斜拉索PE保护层表面伤痕算法的设计。首先,在图像的预处理阶段,对原始图像进行灰度化和滤波处理;其次,运用边缘检测、边界跟踪及Hough变换获得了拉索轮廓的连续边界;然后,利用原始的灰度图像和基于拉索轮廓的掩模板,获得了无背景的拉索表面图像;最后,通过基于图像间空间差分的伤痕检测算法,获得斜拉桥拉索表面伤痕的图像,结果表明该算法能有效地从爬升机器人采集的图像中提取出斜拉索PE保护层表面伤痕的图像。     

The Machine Recognition for Population Feature of Wheat Images Based on BP Neural Network

Recognition and analysis of dynamic information about population images during wheat growth periods can be taken for the base of quantitative diagnosis for wheat growth. A recognition system based on self-learning BP neural network for feature data of wheat population images, such as total green areas and leaves areas was designed in this paper. In addition, some techniques to create favorable conditions for image recognition was discussed, which were as follows: (1) The method of collecting images by a digital camera and assistant equipment under natural conditions in fields. (2) An algorithm of pixei labeling was used to segment image and extract feature. (3)A high pass filter based on Laplacian was used to strengthen image information. The results showed that the ANN system was availability for image recognition of wheat population feature.     

Using an image segmentation and support vector machine method for identifying two locust species and instars

Locusts are agricultural pests around the world. To cognize how locust distribution density and community structure are related to the hydrothermal and vegetation growth conditions of their habitats and thereby providing rapid and accurate warning of locust invasions, it is important to develop efficient and accurate techniques for acquiring locust information. In this paper, by analyzing the differences between the morphological features of Locusta migratoria manilensis and Oedaleus decorus asiaticus, we proposed a semi-automatic locust species and instar information detection model based on locust image segmentation, locust feature variable extraction and support vector machine(SVM) classification. And we subsequently examined its applicability and accuracy based on sample image data acquired in the field. Locust image segmentation experiment showed that the proposed GrabCut-based interactive segmentation method can be used to rapidly extract images of various locust body parts and exhibits excellent operability. In a locust feature variable extraction experiment, the textural, color and morphological features of various locust body parts were calculated. Based on the results, eight feature variables were selected to identify locust species and instars using outlier detection, variable function calculation and principal component analysis. An SVM-based locust classification experiment achieved a semi-automatic detection accuracy of 96.16% when a polynomial kernel function with a penalty factor parameter c of 2 040 and a gamma parameter g of 0.5 was used. The proposed detection model exhibits advantages such as high applicability and accuracy when it is used to identify locust instars of L. migratoria manilensis and O. decorus asiaticus, and it can also be used to identify other species of locusts.     

基于高光谱成像技术的茄子叶片灰霉病早期检测

为建立基于高光谱成像技术的茄子叶片灰霉病早期检测方法,利用高光谱成像系统获取120个茄子叶片在380~1031nm范围的高光谱图像数据,通过主成分分析(PCA)对高光谱数据进行降维,并从中优选出3个特征波段下的特征图像,截取200×150的感兴趣区域图像(ROI),并从每幅特征图像中分别提取均值、方差、同质性、对比度、差异性、熵、二阶矩和相关性等8个基于灰度共生矩阵的纹理特征变量,通过连续投影算法(SPA)提取13个特征变量, 利用最小二乘支持向量机(LS‐SVM)构建茄子叶片灰霉病早期鉴别模型,模型判别准确率为97.5%.说明高光谱成像技术可以用于茄子叶片灰霉病的早期检测.