title: Plant identification through images: Using feature extraction of key points on leaf contours(1.).
abstract: OBJECTIVE
  Because plant identification demands extensive knowledge and complex terminologies, even professional botanists require significant time in the field for mastery of the subject. As plant leaves are normally regarded as possessing useful characteristics for species identification, leaf recognition through images can be considered an important research issue for plant recognition. •
  
  
  METHODS
  This study proposes a feature extraction method for leaf contours, which describes the lines between the centroid and each contour point on an image. A length histogram is created to represent the distribution of distances in the leaf contour. Thereafter, a classifier is applied from a statistical model to calculate the matching score of the template and query leaf. •
  
  
  RESULTS
  The experimental results show that the top value achieves 92.7% and the first two values can achieve 97.3%. In the scale invariance test, those 45 correlation coefficients fall between the minimal value of 0.98611 and the maximal value of 0.99992. Like the scale invariance test, the rotation invariance test performed 45 comparison sets. The correlation coefficients range between 0.98071 and 0.99988. •
  
  
  CONCLUSIONS
  This study shows that the extracted features from leaf images are invariant to scale and rotation because those features are close to positive correlation in terms of coefficient correlation. Moreover, the experimental results indicated that the proposed method outperforms two other methods, Zernike moments and curvature scale space.
authors.affiliation: Department of Information Management, Chien Hsin University of Science and Technology, 229 Chien-Hsin Road, Taoyuan 320, Taiwan.
authors.forename: Chih-Ying
authors.initials: CY
authors.lastname: Gwo
authors.affiliation: Department of Information Management, Chien Hsin University of Science and Technology, 229 Chien-Hsin Road, Taoyuan 320, Taiwan ; Graduate Institute of Biomedical Informatics, Taipei Medical University, Taipei, Taiwan.
authors.forename: Chia-Hung
authors.initials: CH
authors.lastname: Wei
keywords: classifier of statistical model; edge detection; feature extraction; leaf recognition