Image acquisition device, rice freshness detection system and method

Abstract

The application provides an image acquisition device, a rice freshness detection system and method. The inside of a dark box is provided with a light-proof chamber. A determination platform is configured to position a target sample. A camera is included in a camera assembly and is configured to acquire image data of the target sample. A light source assembly includes a main light source and a backlight. The main light source is arranged on the determination platform, the determination platform is located between the camera and the backlight, and the shooting direction of the camera is towards the main light source and the backlight. When the target sample is placed in the light-proof environment in the dark box for shooting, the light noise in the environment can be effectively reduced, the uniformity of the light environment in the shooting process is ensured, and better image data is obtained. The backlight can prevent the surface of the target sample from reflecting light during shooting, the main light source appropriately supplements light, the real color of the target sample can be better shot, the visualization of rice freshness monitoring is improved, and the construction of the digital early warning system for food safety and quality guarantee is effectively ensured.

Description

Technical Field

[0001] This application relates to the field of agricultural product quality testing technology, and in particular to image acquisition devices, rice freshness detection systems and methods. Background Technology

[0002] After paddy rice is hulled and milled, various reactions occur when it is left to stand for a period of time, leading to a decrease in its freshness. Currently, rice freshness is mainly determined using a freshness meter, which is relatively expensive, thus increasing the cost of testing. Research has found that rice of different freshness levels contains different amounts of aldehydes and ketones. These aldehydes and ketones display different colors in a colorimetric solution, so the freshness of the rice can be judged based on the yellow-green hue of the color. Generally speaking, the greener the solution, the fresher the rice; the yellower the solution, the less fresh the rice. However, there are several stages between freshness and staleness where the color change is very subtle and difficult for the human eye to distinguish.

[0003] Traditional rice freshness testing often relies on manual methods. During this process, rice grains tend to clump together when the developing solution is added, preventing complete contact between the grains and the reagent, resulting in incomplete color development and affecting the accuracy of the results. Furthermore, the color changes over time, and untimely recording can lead to distorted judgments. Therefore, using real-world photographs from high-resolution cameras can further enable the visualization and data-driven monitoring of rice freshness, which is of great significance for improving food security and quality assurance, promoting intelligent upgrades in management processes, and fostering sustainable industrial development.

[0004] For photography, many mobile phone cameras or digital cameras allow users to adjust various parameters during shooting, resulting in photos of solutions that suffer from reflections and distortion. While industrial cameras can produce high-resolution, realistic images, the relevant photographic devices and methods still need to address the pressing issues in monitoring the freshness of rice. Summary of the Invention

[0005] Therefore, it is necessary to provide an image acquisition device, a rice freshness detection system, and a method to address the aforementioned technical problems.

[0006] This application provides an image acquisition device, the image acquisition device comprising:

[0007] A dark box, wherein the interior of the dark box is provided with a light-proof chamber;

[0008] A measurement platform, which is assembled in the light-proof chamber of the dark box, is configured to locate the target sample;

[0009] A camera assembly is mounted in the light-proof chamber of the dark box; the camera assembly includes a camera configured to acquire image data of the target sample;

[0010] A light source assembly is installed in the light-proof chamber of the dark box; the light source assembly includes a main light source and a back light source, the main light source is disposed on the measuring platform, the measuring platform is located between the camera and the back light source, and the shooting direction of the camera is towards the main light source and the back light source.

[0011] In one embodiment, the target sample comprises a colorimetric solution mixed with rice; and / or,

[0012] The measurement platform is configured with a measurement area for locating a target sample; the main light source is configured as a ring light source surrounding the measurement area of ​​the measurement platform; and / or,

[0013] The main light source is configured as a 90° light source; and / or,

[0014] The backlight source is directed towards the back of the measuring platform; and / or,

[0015] The backlight is configured as a square light source panel; and / or,

[0016] The backlight is configured as a 25° light source;

[0017] The camera is configured as an industrial camera with aperture and focus adjustment functions.

[0018] In one embodiment, the image acquisition device includes:

[0019] A positioning bracket is disposed in the light-proof chamber of the dark box; wherein at least one of the measuring platform, the camera assembly, and the light source assembly is mounted on the positioning bracket, and the measuring platform, the camera assembly, or the light source assembly is directly or indirectly mounted on the positioning bracket.

[0020] In one embodiment, the positioning bracket includes a main frame, a first positioning frame, a second positioning frame, and a base frame, wherein at least one of the first positioning frame, the second positioning frame, and the base frame is movably assembled to the main frame, and the second positioning frame is located between the first positioning frame and the base frame.

[0021] The camera assembly is mounted on the first positioning frame, the measuring platform is mounted on the second positioning frame, and the backlight is mounted on the base frame.

[0022] In one embodiment, the main frame is configured as a track axis, the track axis is fixedly connected to the base frame, and the first positioning frame and the second positioning frame are movably assembled along the axial direction of the track axis.

[0023] In one embodiment, the image acquisition device includes:

[0024] A first brightness regulator, connected to the main light source control; and / or

[0025] The second brightness regulator is connected to the first brightness regulator, which is connected to the backlight control.

[0026] In one embodiment, the first brightness adjuster is disposed inside the dark chamber and is connected to the measuring platform; and / or,

[0027] The second brightness adjuster is located outside the dark box, and the second brightness adjuster is connected to the backlight control via a data cable, wherein the data cable connecting the second brightness adjuster and the backlight passes through a wire hole in the dark box.

[0028] This application provides a rice freshness detection system, the rice freshness detection system comprising:

[0029] The image acquisition device;

[0030] A sample mixing device, the sample mixing device comprising a robotic arm, a vibrator and a sample tube, the robotic arm being configured to hold the sample tube, and the vibrator being connected to the robotic arm;

[0031] A reagent adding device configured to add reagents to a sample tube of the sample mixing device;

[0032] A data analysis device, which is connected to the image acquisition device via data.

[0033] This application provides a method for detecting the freshness of rice, the method comprising the following steps:

[0034] Weigh out the preset weight of rice and put it into the sample tube;

[0035] The axis of the sample tube is tilted relative to the horizontal plane. The liquid is added in a tilted manner, and a predetermined amount of colorimetric solution is added to the sample tube in multiple times, with a first predetermined time interval between each addition and a second predetermined time interval between additions. The second predetermined time interval is shorter than the first predetermined time interval.

[0036] Mix the rice and colorimetric solution in the sample tube, and let it stand after mixing well.

[0037] After standing, photograph the color of the developing solution in a dark environment.

[0038] In one embodiment, the preset weight of rice is configured to be 3 to 7 grams of rice; and / or,

[0039] The sample tube has a capacity of 50 ml; and / or,

[0040] The predetermined amount of colorimetric solution is prepared as 5 ml to 15 ml of colorimetric solution; and / or,

[0041] The predetermined amount of colorimetric solution is added to the sample tube three times; and / or,

[0042] The first predetermined time is configured to be between 5 and 15 seconds; and / or,

[0043] The second predetermined time is configured to be between 3 and 7 seconds; and / or,

[0044] The angle of inclination of the axis of the sample tube to the horizontal plane is configured to be between 45° and 90°; and / or,

[0045] The mixing time of the rice and the colorimetric solution in the sample tube was configured to be between 5 and 15 seconds; and / or,

[0046] The settling time after mixing was set to 175 to 185 seconds.

[0047] In the aforementioned image acquisition device, rice freshness detection system, and method, when the target sample is placed in a dark box in a light-proof environment for imaging, it effectively reduces ambient light noise, ensures a uniform lighting environment during the imaging process, and obtains better image data. The backlight prevents surface reflections of the target sample during imaging, and the main light source provides appropriate supplementary lighting, allowing for better capture of the true color of the target sample. Therefore, through the coordination of the dark box, backlight, and main light source, the camera can identify and capture the color of the target sample, solving the problem of reflections when photographing liquids (target samples), improving the visualization of rice freshness monitoring, and effectively ensuring the construction of a digital early warning system for food security and quality assurance. Furthermore, the image acquisition device has a simple structure and is easy to use. Attached Figure Description

[0048] Figure 1 A schematic diagram showing the connection between the image acquisition device and the data analysis device provided in this application.

[0049] Figure 2 For example Figure 1 The image acquisition device shown is a top view assembly diagram of the main light source.

[0050] Figure 3 For example Figure 1The image acquisition device shown is a top view assembly diagram of its backlight.

[0051] Figure 4 The projection diagrams for the 90° and 25° light sources provided in this application are shown.

[0052] Icon labels:

[0053] 100. Image acquisition device; 200. Data analysis device; 300. Sample tube;

[0054] 1000, Dark box; 2000, Measuring platform; 3000, Camera assembly; 4000, Light source assembly; 5000, Positioning bracket; 6000, First brightness adjuster; 7000, Second brightness adjuster;

[0055] 1010. Light-proof chamber;

[0056] 3010. Camera;

[0057] 4010, Main light source; 4020, Backlight;

[0058] 5010. Main frame; 5011. First positioning frame; 5012. Second positioning frame; 5013. Base frame. Detailed Implementation

[0059] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0060] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0061] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0062] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0063] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0064] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0065] See Figures 1 to 4As shown, this application provides a rice freshness detection system, which includes an image acquisition device 100, a data analysis device 200, a sample mixing device, and a reagent addition device. The sample mixing device includes a robotic arm, a vibrator, and a sample tube 300. The robotic arm is configured to hold the sample tube 300. The vibrator is connected to the robotic arm, so when activated, it transmits vibration waves to the robotic arm, causing the sample tube 300 held by the robotic arm to vibrate. This vibration waves mix the target sample within the sample tube 300, which includes a colorimetric solution mixed with rice.

[0066] The reagent adding device is configured to add reagent, namely the color developing solution used for rice color development, to the sample tube 300 of the sample mixing device. The data analysis device 200 is connected to the image acquisition device 100, so after the image acquisition device 100 acquires image data of the target sample, the data analysis device 200 can analyze and process the image data to obtain the freshness of the rice.

[0067] Regarding the image acquisition device 100 mentioned above, please refer to... Figure 1 As shown, the image acquisition device 100 may include a dark box 1000, a measuring platform 2000, a camera assembly 3000, and a light source assembly 4000. The dark box 1000 has a light-shielding chamber 1010 inside, thus providing a light-shielding environment. The measuring platform 2000, camera assembly 3000, and light source assembly 4000 are assembled in the light-shielding chamber 1010 of the dark box 1000. The measuring platform 2000 is configured to position the target sample, ensuring the target sample is in a stable, stationary state. The camera assembly 3000 includes a camera 3010, which is configured to acquire image data of the target sample. The light source assembly 4000 includes a main light source 4010 and a back light source 4020. The main light source 4010 is disposed on the measurement platform 2000, which is located between the camera 3010 and the back light source 4020. The shooting direction of the camera 3010 is towards the main light source 4010 and the back light source 4020.

[0068] In one embodiment, the measurement platform 2000 is provided with a measurement area configured for locating a target sample, for example, the measurement area is set at the central position or region of the measurement platform 2000. At this time, the main light source 4010 is configured as a ring light source, which can be set on the outer periphery of the measurement platform 2000, thereby surrounding the measurement area of ​​the measurement platform 2000.

[0069] like Figure 4As shown, the main light source 4010 is configured as a 90° light source, meaning the light emission direction of the main light source 4010 forms a 90° angle with the plane containing the camera 3010. The backlight source 4020 is configured as a square light source plate. The backlight source 4020 is configured as a 25° light source, meaning the light emission direction of the backlight source 4020 forms a 25° angle with the plane containing the camera 3010. The illumination direction of the backlight source 4020 faces the back side of the measurement platform 2000, thus... Figure 1 The direction shown towards camera 3010 provides backlighting for the camera's shooting, improving the shooting effect. Camera 3010 can be configured as an industrial camera 3010 with aperture and focus adjustment functions.

[0070] When the target sample (color developing solution, liquid) is placed in the dark chamber 1000 in a light-proof environment for imaging, ambient light noise is effectively reduced, ensuring a uniform lighting environment during the imaging process and obtaining better image data. The backlight 4020 prevents surface reflection of the target sample during imaging, while the main light source 4010 provides appropriate supplementary lighting, better capturing the true color of the target sample. Therefore, through the cooperation of the dark chamber 1000, backlight 4020, and main light source 4010, the camera 3010 can identify and image the color of the target sample, solving the problem of reflection during liquid (target sample) imaging, improving the visualization of rice freshness monitoring, and effectively ensuring the construction of a digital early warning system for food safety and quality assurance. Furthermore, the image acquisition device 100 has a simple structure and is easy to use. Moreover, the above-mentioned rice freshness detection system integrates the entire process of adding liquid → shaking → imaging → analysis into the rice freshness detection system, reducing human error. It can not only detect whether rice is fresh but also determine the number of days of freshness.

[0071] Continue reading Figure 1 As shown, in one embodiment, the image acquisition device 100 includes a positioning bracket 5000 disposed in the light-proof chamber 1010 of the dark box 1000. At least one of the measuring platform 2000, the camera component 3000, and the light source component 4000 is mounted on the positioning bracket 5000, and the measuring platform 2000, the camera component 3000, or the light source component 4000 is directly or indirectly mounted on the positioning bracket 5000. For example, in one embodiment, the positioning bracket 5000 includes a main frame 5010, a first positioning frame 5011, a second positioning frame 5012, and a base frame 5013. At least one of the first positioning frame 5011, the second positioning frame 5012, and the base frame 5013 is movably mounted on the main frame 5010, and the second positioning frame 5012 is located between the first positioning frame 5011 and the base frame 5013. The camera component 3000 is mounted on the first positioning frame 5011, the measuring platform 2000 is mounted on the second positioning frame 5012, and the backlight 4020 is mounted on the base frame 5013.

[0072] In one embodiment, the main frame 5010 is configured as a track shaft, which is fixedly connected to the base frame 5013. The first positioning frame 5011 and the second positioning frame 5012 are movably assembled along the axial direction of the track shaft. For example, the first positioning frame 5011 and the second positioning frame 5012 are assembled to the main frame 5010 by means of a snap-fit ​​mechanism, a bolt mechanism, etc., and are fixed to a specific position of the main frame 5010 by means of snap-fit ​​or threaded connection. At the same time, they can also move relative to the main frame 5010 by releasing the snap-fit ​​or threaded connection, thereby movably assembling along the axial direction of the track shaft.

[0073] In one embodiment, the image acquisition device 100 includes a first brightness regulator 6000 and a second brightness regulator 7000. The first brightness regulator 6000 is controlled and connected to a main light source 4010, thereby adjusting the brightness of the main light source 4010 as needed. The first brightness regulator 6000 is also controlled and connected to a backlight source 4020, thereby adjusting the brightness of the backlight source 4020 as needed. In one embodiment, the first brightness regulator 6000 is disposed inside a dark box 1000 and is connected to a measurement platform 2000. The second brightness regulator 7000 is disposed outside the dark box 1000 and is controlled and connected to the backlight source 4020 via a data cable, wherein the data cable connecting the second brightness regulator 7000 and the backlight source 4020 passes through a wire hole in the dark box 1000 in a sealed manner.

[0074] This application provides a method for detecting the freshness of rice. The method includes the following steps: weighing a predetermined weight of rice and placing it into a sample tube 300; controlling the axis of the sample tube 300 to be tilted relative to the horizontal plane, adding a predetermined amount of color-developing solution to the sample tube 300 in multiple portions using an inclined liquid addition method, with each addition spaced at a first predetermined time interval and each addition accompanied by a second predetermined time interval, the second predetermined time being shorter than the first predetermined time interval; mixing the rice and color-developing solution in the sample tube 300, mixing thoroughly, and then allowing it to stand; after standing, photographing the solution color of the color-developing solution in a light-protected environment.

[0075] The tilting liquid addition refers to controlling the liquid reagent to flow down the sample tube 300 in a spiral shape along the tube wall when adding liquid reagent to the tilted sample tube 300, thereby avoiding direct impact of the liquid reagent on the sample (rice grains) and preventing sample clumping and bubble generation.

[0076] In one embodiment, the preset weight of rice is configured to be 3 to 7 grams, such as 3 grams, 4 grams, 5 grams, 6 grams, 7 grams, etc.; the sample tube 300 has a capacity of 50 ml; the predetermined amount of colorimetric solution is configured to be 5 ml to 15 ml, such as 5 ml, 6 ml, 7 ml, 8 ml, 9 ml, 10 ml, 11 ml, 12 ml, 13 ml, 14 ml, 15 ml, etc.; the predetermined amount of colorimetric solution is added to the sample tube 300 three times; the first predetermined time is configured to be 5 to 15 seconds, such as 5 seconds, 6 seconds, 7 seconds, 8 seconds, 9 seconds, 10 seconds, 11 seconds, 12 seconds, 13 seconds, 14 seconds, 15 seconds, etc.; the second predetermined time is configured to be 3 to 7 seconds, such as 3 seconds, 4 seconds, 5 seconds, 6 seconds, 7 seconds, etc.

[0077] The tilt angle of the axis of the sample tube 300 relative to the horizontal plane is configured to be between 45° and 90°, which is the tilt angle for adding liquid at an angle, such as 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85°, 90°, etc.; the mixing time of rice and colorimetric solution in the sample tube 300 is configured to be between 5 seconds and 15 seconds, such as 5 seconds, 6 seconds, 7 seconds, 8 seconds, 9 seconds, 10 seconds, 11 seconds, 12 seconds, 13 seconds, 14 seconds, 15 seconds, etc.; the standing time after mixing is configured to be between 175 seconds and 185 seconds, such as 175 seconds, 176 seconds, 177 seconds, 178 seconds, 179 seconds, 180 seconds, 181 seconds, 182 seconds, 183 seconds, 184 seconds, 185 seconds, etc.

[0078] Taking a 25° tilt angle for liquid addition as an example, the following operating steps can be selected:

[0079] Step 1: Set the sample tube to a 30° tilt.

[0080] Secure a 50ml sample tube 300 containing a preset weight of rice (e.g., 10g) to the gripper of the robotic arm. Adjust the robotic arm so that the axis of the sample tube 300 forms a 55° angle with the horizontal plane (the tilt angle can be adjusted within the range of 45°-90°). At this time, the rice grains in the sample tube 300 will naturally accumulate at the bottom of the tube near the opening.

[0081] Step 2: Positioning the liquid addition tube

[0082] Move the end of the liquid addition tube of the reagent addition device to the opening of the sample tube 300, and adjust the position of the liquid addition tube so that the outlet is close to the upper side of the inner wall of the sample tube 300 (i.e. the inner wall of the higher position in the tilted state).

[0083] Step 3: Gradient addition of liquid

[0084] While the sample tube is continuously rotating at 300°, begin adding the colorimetric solution in portions:

[0085] First addition: Slowly add 3ml of color developing solution at a rate of 1ml / second. The liquid will flow down the rotating tube in a spiral motion, evenly wetting the surface of the rice grains.

[0086] Intermittent oscillation: After adding the liquid, start the vibrator to oscillate for 5 seconds to allow the rice to initially come into contact with a small amount of color developing solution.

[0087] Second addition: After a 10-second interval, add 3 ml of colorimetric reagent at the same speed as before. Shake for 5 seconds after adding the reagent.

[0088] Third addition: After a 10-second interval, add another 4 ml of color developing solution.

[0089] Final mixing: After adding the liquid, shake for 10 seconds to ensure that the rice and the color developing solution are fully mixed.

[0090] Example 1

[0091] Sample pretreatment: Weigh 5g of rice into a 50ml sample tube 300.

[0092] Centrifugal gradient addition method: Add 10ml of colorimetric solution in three gradients, i.e., add 3ml in the first addition, 3ml in the second addition, and 4ml in the third addition, with a 10-second interval and a 5-second oscillation after each addition.

[0093] Anti-caking control: Add liquid at a 25° tilt angle, with the axis of the 300 sample tube at a 55° angle to the horizontal plane. Mix thoroughly for 10 seconds and let stand for 180 seconds.

[0094] Photography: After standing for 180 seconds, the camera 3010 takes photos at set intervals in a dark environment. The photo interval can be set to capture image data of the color developing solution and record the solution color at different times.

[0095] Example 2

[0096] Based on the sample pretreatment, centrifugation gradient liquid addition method, anti-agglomeration control, and sample detection method described in the previous examples, the following steps are continued:

[0097] Freshness Model Establishment: Rice of varying freshness was prepared and stored for 0, 1, 2, 3, 5, 7, 15, 30, 45, 60, 90, 120, 150, and 180 days. Samples were taken daily for testing, and standard chromatograms of rice at different freshness levels were prepared to establish different freshness models.

[0098] Sample testing (based on the sample testing method in Example 1): After sample testing, the results are compared with the freshness model to provide the rice freshness and reference number of days.

[0099] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0100] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An image acquisition device, characterized in that, The image acquisition device includes: A dark box, wherein the interior of the dark box is provided with a light-proof chamber; A measurement platform, which is assembled in the light-proof chamber of the dark box, is configured to locate the target sample; A camera assembly is mounted in the light-proof chamber of the dark box; the camera assembly includes a camera configured to acquire image data of the target sample; A light source assembly is installed in the light-proof chamber of the dark box; the light source assembly includes a main light source and a back light source, the main light source is disposed on the measuring platform, the measuring platform is located between the camera and the back light source, and the shooting direction of the camera is towards the main light source and the back light source.

2. The image acquisition device according to claim 1, characterized in that, The target sample includes a colorimetric solution mixed with rice; and / or, The measuring platform is provided with a measuring area, which is configured to locate the target sample. The main light source is configured as a ring light source, which surrounds the measuring area of ​​the measuring platform. And / or, The main light source is configured as a 90° light source; and / or, The backlight source is directed towards the back of the measuring platform; and / or, The backlight is configured as a square light source panel; and / or, The backlight is configured as a 25° light source; The camera is configured as an industrial camera with aperture and focus adjustment functions.

3. The image acquisition device according to claim 1, characterized in that, The image acquisition device includes: A positioning bracket is disposed in the light-proof chamber of the dark box; wherein at least one of the measuring platform, the camera assembly, and the light source assembly is mounted on the positioning bracket, and the measuring platform, the camera assembly, or the light source assembly is directly or indirectly mounted on the positioning bracket.

4. The image acquisition device according to claim 3, characterized in that, The positioning bracket includes a main frame, a first positioning frame, a second positioning frame, and a base frame. At least one of the first positioning frame, the second positioning frame, and the base frame is movably assembled to the main frame, and the second positioning frame is located between the first positioning frame and the base frame. The camera assembly is mounted on the first positioning frame, the measuring platform is mounted on the second positioning frame, and the backlight is mounted on the base frame.

5. The image acquisition device according to claim 4, characterized in that, The main frame is configured as a track axis, which is fixedly connected to the base frame. The first positioning frame and the second positioning frame are movably assembled along the axial direction of the track axis.

6. The image acquisition device according to claim 1, characterized in that, The image acquisition device includes: A first brightness regulator, connected to the main light source control; and / or The second brightness regulator is connected to the first brightness regulator, which is connected to the backlight control.

7. The image acquisition device according to claim 6, characterized in that, The first brightness adjuster is disposed inside the dark chamber and is connected to the measuring platform; and / or, The second brightness adjuster is located outside the dark box, and the second brightness adjuster is connected to the backlight control via a data cable, wherein the data cable connecting the second brightness adjuster and the backlight passes through a wire hole in the dark box.

8. A rice freshness detection system, characterized in that, The rice freshness detection system includes: The image acquisition apparatus as described in any one of claims 1-7; A sample mixing device, the sample mixing device comprising a robotic arm, a vibrator and a sample tube, the robotic arm being configured to hold the sample tube, and the vibrator being connected to the robotic arm; A reagent adding device configured to add reagents to a sample tube of the sample mixing device; A data analysis device, which is connected to the image acquisition device via data.

9. A method for detecting the freshness of rice, characterized in that, The method for detecting the freshness of rice includes the following steps: Weigh out the preset weight of rice and put it into the sample tube; The axis of the sample tube is tilted relative to the horizontal plane. The liquid is added in a tilted manner, and a predetermined amount of colorimetric solution is added to the sample tube in multiple times, with a first predetermined time interval between each addition and a second predetermined time interval between additions. The second predetermined time interval is shorter than the first predetermined time interval. Mix the rice and colorimetric solution in the sample tube, and let it stand after mixing well. After standing, photograph the color of the developing solution in a dark environment.

10. The method for detecting rice freshness according to claim 9, characterized in that, The preset weight of rice is configured to be 3 to 7 grams; and / or, The sample tube has a capacity of 50 ml; and / or, The predetermined amount of colorimetric solution is prepared as 5 ml to 15 ml of colorimetric solution; and / or, The predetermined amount of colorimetric solution is added to the sample tube three times; and / or, The first predetermined time is configured to be between 5 and 15 seconds; and / or, The second predetermined time is configured to be between 3 and 7 seconds; and / or, The angle of inclination of the axis of the sample tube to the horizontal plane is configured to be between 45° and 90°; and / or, The mixing time of the rice and the colorimetric solution in the sample tube was configured to be between 5 and 15 seconds; and / or, The settling time after mixing was set to 175 to 185 seconds.

Images