Image-based plant nutrient status analysis: An overview

Following the rapid advancement in both fields of precision farming and multimedia technology, image-based plant nutrient status analysis as a nondestructive method is currently playing a more important role in optimizing N fertilizer inputs, improving crop yields and resource use efficiency than conventional soil and plant analysis. This development is primarily based on the supposition that the foliar appearance features such as color or textures can indicate explicitly the nutrient status of the plant leaf. Many results have been reported in the last few years. However, those results are mostly diverse and mainly focused on a very narrow field, therefore missing the information with which they are each other related. In this paper, we provide an overview on state-of-the-art of these methods and connect them together with techniques from three aspects: biometric modeling, image acquisition and image processing. For each aspect, the respective technical schemes are reviewed and compared with each other, thus based on the discussions, the future trends are pointed out.