Select the most appropriate morphologic characteristic to distinguish weeds in wheat fields by image processing technique

In order to select the most appropriate morphological characteristics of weeds in wheat fields in Khuzestan province, 16 species of the most common broadleaf weeds were selected.Collected species included: Ammi majus L., Anagallis spp., Beta vulgaris subsp. maritima (L.), Carthamus tinctorius L., Chenopodium murale L.,Convolvulus arvensis L, Lactuca serriola L., Malva spp.,Rumex dentatus L., Scorpiurus muricatus L., Silybum marianum L., Sinapis arvensis L., Sonchus tenerrimus L., Stelaria media L., Veronica persica Poir., and Vicia villosa Roth. For any species, five samples (as five replications) were photographed and images were analysed using image processing. Wheat, also, was photographed as control. After isolating images from background and tagging them, seven morphological characteristics including area, perimeter, aspect ratio (length to diameter ratio), rectangularity, area ratio of convex hull, perimeter ratio of convex hull, sphericity, form factor and eccentricity of each weed species and wheat were extracted. Results showed that the best morphological characteristics to distinguish broadleaf weeds from wheat were aspect ratio and sphericity. So that, compared to the weed species, aspect ratio was greatest (19.79) in wheat. After that, caterpillar-plant(9.71) and safflower (5.90) were greatest. The sphericity of wheat was the lowest (0.05). Considering the narrow shape of wheat leaves and the significant difference in leaf shape with broad-leaved species, this characteristic can be very useful for identifying and distinguishing wheat from broadleaf species at the field.