Technical Note: Extraction of Wing Venation Characteristics by Image Analysis

Abstract

Wing venation characteristics, such as the wing diagram and coordinates of vein junctions, are species-specific and are usually used in studies of insect identification. Image analysis methods are quick and precise means to measure these characteristics. An image analysis method is proposed that enables extraction of the wing diagram and automatic identification of vein junctions. A color image of an insect wing is converted to a binary image of wing venation based on thresholding. A distance-to-boundary map of the complement of the binary image is computed using a distance transform function. The vein skeleton is obtained by a watershed transform. The lookup table method is applied to find coordinates of vein junctions. The proposed method is capable of producing a smooth vein skeleton diagram and can extract the coordinates of vein junctions. This approach is not limited to high-quality images and is simple because the characteristics are obtained almost simultaneously. The experimental results showed that the proposed method is repeatable and useful for wing analysis.