Chroma+, a new automontage method of image background selection for Insects and other structurally complex objects

Abstract

Obtaining taxonomic-grade images is a vital part of probably every present-day morphological study of insects, even though the task itself is perceived as a “necessary evil” due to high investment of both time and effort to produce representable images. Cleaning the background and making it appear as a solid color of known properties is probably one of the most time-demanding tasks. Several techniques have been developed to reduce the time requirement; the most convenient and cost-effective one presumably being the chroma isolation. This method uses a green background that can be isolated and conveniently replaced with another picture or solid color, as used in the film industry. However, the main drawback of this technique is spilling of color onto the object, which is unavoidable and can be corrected only by sacrificing the true color of the object to some extent. Our improved Chroma+ method is based on classical chroma isolation workflow and helps to overcome this problem by taking an additional image of the object with a neutral color background and applying a selection obtained from the chroma-isolated picture on it. This technique is, in terms of the resulting image quality, superior to classical chroma isolation, while the time difference between these two methods is negligible. Furthermore, it does not require any additional equipment (hardware or software), thus being accessible to both employed taxonomists, low budget laboratories, and enthusiasts.