Plant systematics can be classified and recognized based on their reproductive system (flowers) and leaf morphology. Neural networks is one of the most popular machine learning algorithms for plant leaf classification. The commonly used neutral networks are artificial neural network (ANN), probabilistic neural network (PNN), convolutional neural network (CNN), k-nearest neighbor (KNN) and support vector machine (SVM), even some studies used combined techniques for accuracy improvement. The utilization of several varying preprocessing techniques, and characteristic parameters in feature extraction appeared to improve the performance of plant leaf classification. The findings of previous studies are critically compared in terms of their accuracy based on the applied neural network techniques. This paper aims to review and analyze the implementation and performance of various methodologies on plant classification. Each technique has its advantages and limitations in leaf pattern recognition. The quality of leaf images plays an important role, and therefore, a reliable source of leaf database must be used to establish the machine learning algorithm prior to leaf recognition and validation.

Herbs are widely utilized in food and health industries. Their beneficial effects to the human body have been attributed to the presence of active phytochemical ingredients with some efficiency for disease treatment as well as for beauty and health enhancement. Public awareness on the adverse effects of synthetic chemical products also increased the demand for herbal products. Highly efficient herbal processing and extraction technologies have been developed to obtain the optimal amounts of active ingredients from herbs and cope with the rising demands for herbal products. This article reviews the state-of-the-art development in herbal processing and extraction methods from the year 1991 until 2015. We start with a brief history of herbal usage, followed by descriptions of 10 types of extraction processes and critical analysis of their relative advantages and disadvantages. Scale-up considerations of the extraction methods are shared, and a highlight of the current and future challenges facing the herbal industry is presented.