## 4 Image Acquisition Method and Information Processing of Yinghong No. 9 Tea Leaves  
### Materials and Methods  
Taking the Yinghong No. 9 tea leaves moisture content detection device as the test platform, its composition is shown in Figure 5. The platform consisted of a dark room, a control room, and an electronic scale of the model Leqi CN-LQC30001 (Kunshan City, Jiangsu Province, China, Youkeweit Electronic Technology Co., Ltd.), with an accuracy of 0.01 g. The dark box and control room are described in detail in Section 3.  
The test material was Yinghong No. 9 tea leaves, which were collected from the tea garden of Guangdong Yingjiu Manor Green Industry Development Co., Ltd., on November 6 th and shipped back to South China Agricultural University. In order to ensure the quality of the tea leaves, the tea leaves harvested in the tea garden were placed in a fresh-keeping box, and approximately 5 kg of the wilted or damaged tea leaves was removed from the fresh-keeping box. The remaining tea leaves were divided into seven samples, each sample approximately 600 g, and the specific experimental steps were as follows:  
Step 1: Place the electronic scale on the test bench for leveling.  
Step 2: Place the iron frame on the electronic scale and perform a zero adjustment. After reading that the electronic scale is stable, click \"tare\".  
Step 3: Place and spread the tea leaves evenly on the iron plate until the electronic scale shows approximately 600 g.  
Step 4: Fix the dark box above the tea leaves sample to ensure that the dark box does not contact the electronic scale and the iron plate and adjust the camera focus until the image is clear.  
Step 5: Set the control room to collect the weight of the tea leaves and an image of the tea leaves every 5 min.  
Step 6: After 10 h of moisture content loss, take out the tea leaves and put them into an aluminum box.  
Step 7: Preheat the electric thermostatic drying oven to 102 degrees, and then put the aluminum box into the electric thermostatic drying oven. After 4 h, take it out, weigh it, and record the data. Then, put the aluminum box into the electric thermostatic drying oven for 1 h, and weigh it until the aluminum box reaches a constant weight state. Finally, calculate the dry weight of the tea leaves.  
In each experiment, 120 groups of tea leaves images and tea leaves weights were collected, and a total of 840 groups of tea leaves images and tea leaves weights were obtained. For a certain time, t, referring to the GB/T 8304-2013 standard in Chinese to measure the moisture content of the tea leaves, the moisture content of the tea leaves was calculated using Equation (4). From the calculation, it was shown that the moisture  
Figure 5: The Yinghong No. 9 tea leaves moisture content test platform: (1) Iron frame; (2) camera mount; (3) camera; (4) LED; (5) electronic scale.  
content of the tea leaves dropped from 78.48% to 53.14%, and the average moisture content decreased by 0.09% every 5 min, which enriched the labeling range of the tea leaves images. The obtained images and moisture contents were divided into the training set and the test set at a ratio of 4:1.  
\[\mathrm{W(t)}=\frac{\mathrm{G1(t)-G2}}{\mathrm{G1(t)-G3}}\times 100\% \tag{4}\]  
Here, \(\mathrm{G_{1}(t)}\) is the weight of the fresh tea leaves at time t, \(\mathrm{G_{2}}\) is the dry tea leaves weight, \(\mathrm{G_{3}}\) is the aluminum box weight, and \(\mathrm{W(t)}\) is the moisture content of the tea leaves at time t.