Nitrogen evaluation of winter wheat based on color features of canopy images

The nitrogen status (N-status) evaluation of winter wheat by using computer image processing technology to extract the color features of wheat canopy image was researched in this paper. In the paper, seven statistics of color histogram were calculated based on these color components: R,G,B,H,S,I and L from RGB and HIS color system. The different color features were selected from the statistics for expressing seven main growth periods after reviving of wheat. The results showed that these features could efficiently express the canopy color of wheat under varied N-status, especially to express low N-status and high N-status, and showed significant diversity of canopy color of wheat with different modes and phases of applying nitrogen fertilizer under the same total nitrogen quantity. This approach can provide an effective way to evaluate N-status of wheat by using wheat canopy image