Abstract：Since the conventional shape descriptors focus on shape reexpression and the stochastic character of leaf shape is neglected, an effective plant leaf shape descriptor is proposed based on latent Dirichlet allocation (LDA) model. A corresponding leaf shape recognition framework is also constructed. Firstly, the plant leaf shape is transformed and represented as a multi-scale bag-of-words model, and thus the space interaction relationship is introduced into the leaf shape generative model. Furthermore, a leaf shape generative model is established via LDA model, and then the leaf shape descriptor is designed by the extracted shape distribution parameters in the LDA model. Finally, k-nearest neighbor (KNN) method is applied to the plant leaf shape classification. Experimental results demonstrate that the leaf shape descriptor combined with LDA model effectively improves the shape classification accuracy, especially for the plants of different classes but with a roughly similar shape of leaf. The proposed method obtains a higher classification accuracy compared with the conventional shape descriptor.
[1] EL-GHAZAL A, BASIR O, BELKASIM S. Invariant Curvature-Based Fourier Shape Descriptors. Journal of Visual Communication and Image Representation, 2012, 23(4): 622-633. [2] WANG X F, HUANG D S, DU J X, et al. Classification of Plant Leaf Images with Complicated Background. Applied Mathematics and Computation, 2008, 205(2): 916-926. [3] DU J X, ZHAI C M, WANG Q P. Recognition of Plant Leaf Image Based on Fractal Dimension Features. Neurocomputing, 2013, 116: 150-156. [4] LEI Y K, ZOU J W, DONG T B, et al. Orthogonal Locally Discri-minant Spline Embedding for Plant Leaf Recognition. Computer Vision and Image Understanding, 2014, 119: 116-126. [5] GHASAB M A J, KHAMIS S, MOHAMMAD F, et al. Feature Decision-Making Ant Colony Optimization System for an Automated Recognition of Plant Species. Expert Systems with Applications, 2015, 42(5): 2361-2370. [6] CHAKI J, PAREKH R, BHATTACHARYA S. Plant Leaf Recognition Using Texture and Shape Features with Neural Classifiers. Pa-ttern Recognition Letters, 2015, 58: 61-68. [7] ZHAO C, CHAN S S F, CHAM W K, et al. Plant Identification Using Leaf Shapes-A Pattern Counting Approach. Pattern Recognition, 2015, 48(10): 3203-3215. [8] NOVOTNY/ P, SUK T. Leaf Recognition of Woody Species in Central Europe. Biosystems Engineering, 2013, 115(4): 444-452. [9] DU J X, WANG X F, ZHANG G J. Leaf Shape Based Plant Species Recognition. Applied Mathematics and Computation, 2007, 185(2): 883-893. [10] PETER A M, RANGARAJAN A. Maximum Likelihood Wavelet Density Estimation with Applications to Image and Shape Matching. IEEE Trans on Image Processing, 2008, 17(4): 458-468. [11] EL-GHAZAL A, BASIR O, BELKASIM S. Farthest Point Distance: A New Shape Signature for Fourier Descriptors. Signal Processing: Image Communication, 2009, 24(7): 572-586. [12] SHU X, PAN L, WU X J. Multi-scale Contour Flexibility Shape Signature for Fourier Descriptor. Journal of Visual Communication and Image Representation, 2015, 26: 161-167. [13] ZHANG D S, LU G J. Shape-Based Image Retrieval Using Generic Fourier Descriptor. Signal Processing: Image Communication, 2002, 17(10): 825-848. [14] MOKHTARIAN F, MACKWORTH A. Scale-Based Description and Recognition of Planar Curves and Two-Dimensional Shapes. IEEE Trans on Pattern Analysis and Machine Intelligence, 1986, 8 (1): 34-43. [15] EL-GHAZAL A, BASIR O, BELKASIM S. Invariant Curvature-Based Fourier Shape Descriptors. Journal of Visual Communication and Image Representation, 2012, 23(4): 622-633. [16] BELONGIE S, MALIK J, PUZICHA J. Shape Matching and Object Recognition Using Shape Contexts. IEEE Trans on Pattern Analysis and Machine Intelligence, 2002, 24(4): 509-522. [17] LING H B, JACOBS D W. Shape Classification Using the Inner-Distance. IEEE Trans on Pattern Analysis and Machine Intelligence, 2007, 29(2): 286-299. [18] HU R X, JIA W, LING H B, et al. Multiscale Distance Matrix for Fast Plant Leaf Recognition. IEEE Trans on Image Processing, 2012, 21(11): 4667-4672. [19] BLEI D M, NG A Y, JORDAN M I. Latent Dirichlet Allocation. Journal of Machine Learning Research, 2003, 3: 993-1022. [20] URDIALES C, BANDERA A, SANDOVAL F. Non-parametric Planar Shape Representation Based on Adaptive Curvature Fun-ctions. Pattern Recognition, 2002, 35(1): 45-53. [21] ZAHN C T, ROSKIES R Z. Fourier Descriptors for Plane Closed Curves. IEEE Trans on Computers, 1972, C-21(3): 269-281.
2016, Vol. 29 
