# Wheat Quantity Monitoring Methods Based on Inventory Measurement and SVR Prediction Model
## 1 Introduction  
Grain is an important strategic material for national stability and development. Ensuring food security is a long-term strategic task for our country that directly affects national security [1]. To ensure that grain can meet the needs of the people and respond to emergencies, China has set up a three-tier grain storage system with nearly 10,000 grain warehouses at all levels, and the existing grain storage capacity has reached 500 million tons [2]. In order to strengthen the supervision and inspection of the amount of grain stored in grain depots and to ensure the authenticity and reliability of the amount of grain stored in grain depots, it is important to study the amount of grain stored in grain depots. Because wheat has excellent storage resistance, the storage time can reach 3-5 years under normal temperatureconditions, and the storage time at low temperature (15 \({}^{\circ}\)C) can reach 5-8 years; thus, the existing medium and long-term grain storage in China is mainly wheat. However, the grain volume in the grain store gradually changes during wheat storage due to storage environment, changes in water content, grain settling, natural losses, and other factors, which makes grain quantity inspection difficult. Inventory and spot checks mainly rely on traditional manual methods for inspection and auditing, which have problems of low efficiency and high cost [3,4]. To address these issues, researchers in relevant fields have conducted extensive research and made numerous attempts. As a result, various technologies for monitoring the quantity of grain in granaries are continuously emerging, playing a crucial role in safeguarding national food security [5]. Currently, there are two primary methods for monitoring the quantity of grain in granaries: direct measurement and indirect measurement [6]. The direct measurement method involves manual weighing and pressure sensor measurement. The grain depot is quite large, with each warehouse capable of storing close to 10,000 tons of grain. However, there is currently no sensor available that can accurately weigh the grain at the bottom of the granary. The pressure sensor method involves placing numerous pressure sensors throughout the grain bin to measure the pressure of grain on the side walls and bottom. By using the conversion relationship between pressure and gravity on the grain in the bin, the quantity of grain can be determined [7, 8, 9]. However, it is important to note the Janssen effect, which states that when the grain piles in the granary reach a certain height, the force at the bottom of the granary no longer increases with the addition of more grain. While the pressure sensor method takes into account the influence of sidewall pressure, its effectiveness still needs to be verified. Although many scholars have carried out a lot of research on the granary weighing measurement method, there is still no major breakthrough and no feasible plan for practical application. The indirect measurement method involves using different technical means to measure the volume of grain silos and then combining it with grain density to determine the quantity of grain indirectly. Various technologies are employed in this method, such as 3D laser scanning, ultrasonic measurement, electromagnetic wave detection, wide-beam radar detection, and machine vision detection. The electromagnetic wave detection method involves using a radar antenna placed on the surface of a grain pile to scan the entire surface horizontally. This allows for the detection of internal granaries by analyzing the signals reflected from electromagnetic wave targets [10,11]. However, this method must take into account various factors such as grain type, temperature, and impurity content. To enhance the accuracy of the measurement data, it is important to continuously establish a real-time model that relates grain density to the dielectric constant.