02360naa a2200277 a 450000100080000000500110000800800410001902400540006010000210011424501000013526000090023552015120024465000200175665000260177665000110180265300310181365300210184465300240186565300190188965300270190865300190193570000170195470000170197170000170198877300770200510092652020-01-17       2006    bl uuuu     u00u1 u    #d7 ahttps://doi.org/10.1016/j.compag.2005.09.0042DOI1 aCAMARGO NETO, J.  aPlant species identification using Elliptic Fourier leaf shape analysis.h[electronic resource]  c2006  aElliptic Fourier (EF) and discriminant analyses were used to identify young soybean (Glycine max (L.) merrill), sunflower (Helianthus pumilus), redroot pigweed (Amaranthus retroflexus) and velvetleaf (Abutilon theophrasti Medicus) plants, based on leaf shape. Chain encoded, Elliptic Fourier harmonic functions were generated based on leaf boundary. A complexity index of the leaf shape was computed using the variation between consecutive EF functions. Principle component analysis was used to select the Fourier coefficients with the best discriminatory power. Canonical discriminant analysis was used to develop species identification models based on leaf shapes extracted from plant color images during the second and third weeks after germination. The classification results showed that plant species during the third week were successfully identified with an average of correct classification rate of 89.4%. The discriminant model correctly classified on average: 77.9% of redroot pigweed, 93.8% of sunflower, 89.4% of velvetleaf and 96.5% of soybean. Using all of the leaves extracted from the second and the third weeks, the overall classification accuracy was 89.2%. The discriminant model correctly classified 76.4% of redroot pigweed, 93.6% of sunflower, 81.6% of velvetleaf, 91.5% of soybean leaf extracted from trifoliolate and 90.9% of soybean unifoliolate leaves. The Elliptic Fourier shape feature analysis could be an important and accurate tool for weed species identification and mapping.  aComputer vision  adiscriminant analysis  aLeaves  aAnálise de forma de folha  aElliptic Fourier  aEspécies de planta  aMachine vision  aReconhecimento padrão  aShape features1 aMEYER, G. E.1 aJONES, D. D.1 aSAMAL, A. K.  tComputers and Electronics in Agriculturegv. 50, n. 2, p. 121-134, 2006.