Resumo

RINCON GUERRERO, Natalia; OLARTE QUINTERO, Manuel Andrés  e  PEREZ NARANJO, Juan Carlos. Leaf Area Measurement in Photographs Taken with a Webcam, a Cell Phone or a Semi Professional Camera. Rev. Fac. Nac. Agron. Medellín [online]. 2012, vol.65, n.1, pp.6399-6405. ISSN 0304-2847.

Abstract. Leaf area is a plant trait widely assessed in plant science. It is measured by using expensive specialized equipment which is not available to all laboratories. To overcome these constraints, in order to measure plant leaf area, along this research we coupled a free image analysis software (ImageJ) to the use of cellular phone, web o semi professional digital cameras. The sensitivity of this system was initially tested by challenging the real area of 18 pieces of green colored paper to the area estimated by a commercial leaf area meter or obtained from pictures taken by each digital camera. A further correlative based test, was designed to obtain leaf area measurements from pictures of those digital cameras or by using the leaf area meter on detached leaves of five plant species, varying in color and morphology. In the first test, real area values were well correlated (r = 0.99) to area values obtained from the leaf area meter or from digital images obtained from each digital camera. During the second test with detached leaves, high correlation coefficients (r=1) were also obtained among area measurements made by the leaf area meter and from each leaf digital picture. A regression analysis between leaf area measurements with these systems indicated a maximum deviation of 2% when areas of the cellular phone camera are compared to those obtained from the leaf area meter. These results foresee on this system a promising and easy to use tool for research. The components used here are true mobile and are widely available at a very low cost. This should help researchers on plant science even under very limiting technological conditions.

Palavras-chave : Image analyses; digital camera; leaf area meter; imageJ.

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