Image-based soil characterization: A review on smartphone applications
Mojtaba Naeimi, Prasad Daggupati, Asim Biswas
Abstract
• Image-based soil characterization is becoming a standard practice in soil science. • Smartphones streamline soil analysis as a practical alternative to traditional methods. • Practical challenges in smartphone-based soil characterization are being addressed. • Illumination variability and Soil Moisture Content present significant challenges. In the context of global sustainability challenges, precise soil characterization is pivotal for informed soil management and land use planning as ‘better measurement can only lead to better management’. Soil color serves as a fundamental indicator, revealing critical insights into soil properties and thus, facilitating a deeper understanding of soil behavior. Recent advancements in smartphone technology, equipped with sophisticated imaging capabilities, have transformed traditional soil analysis methods. This review is timely and necessary as it captures the current advancements in image-based soil characterization, with a special emphasis on the expanding use of smartphone technology in this field. Through an exhaustive scientometric analysis, this paper identifies key soil properties, analyzes thematic concentrations within the literature, and highlights the important contributions of leading researchers, as well as the geographic distribution of studies. It thoroughly examines the methodologies employed in processing soil images obtained via smartphones, covering aspects such as image acquisition, segmentation, color space conversion, and feature extraction, which facilitate the development of robust predictive models for soil attributes. Furthermore, this review identifies and addresses the prevalent challenges in smartphone-based soil analysis, including illumination variability, soil moisture content, and device-specific limitations. Proposed future research directions aim to overcome these hurdles through technological advancements in camera capabilities, real-time processing, community-driven data collection, and augmented reality integration, significantly improving the accuracy, efficiency, and accessibility of soil analyses. By consolidating and critically evaluating these innovative approaches, this review not only underscores the transformative potential of smartphone technology in soil characterization but also serves as a catalyst for future interdisciplinary research, setting a progressive agenda for enhancing global soil management practices.