A colony counter for food quality testing

Abstract

This invention provides a colony counter for food quality testing, comprising a testing chamber. A rotating tray is mounted on a dynamic testing base fixedly installed at the bottom inside the testing chamber. An integrated controller is fixedly installed outside the testing chamber, controlling the dynamic testing base, LED light sources, and a high-resolution camera. LED light sources are fixedly installed on both sides of the upper inside of the testing chamber via brackets. A high-resolution camera is fixedly installed in the middle of the upper inside of the testing chamber. A front baffle is fixedly installed on the upper inside of the testing chamber. This invention eliminates the blind spots of fixed light sources by using tilted LED light sources on both sides and a dynamic testing base with a rotating tray. The dynamic change of colony shadows during rotation improves the recognition effect. An electromagnetic sliding block controls a trigger block, and a photoelectric sensor accurately triggers the image taking, eliminating the need for manual angle adjustment and completing multi-angle imaging with a single plate placement.

Description

Technical Field

[0001] This utility model belongs to the field of colony counting technology, and in particular relates to a colony counter for food quality testing. Background Technology

[0002] Food safety is a core concern in people's livelihood, and the number of microbial colonies in food is a key indicator for assessing food hygiene, freshness, and risk of spoilage. Colony counts directly reflect the level of hygiene control in food production and processing, and can also predict the safety and stability of food during storage and transportation. Against this backdrop, colony counters, as core equipment in food quality testing, directly impact the effectiveness of food safety supervision through their accuracy and efficiency.

[0003] In existing technologies, traditional food colony counters generally employ a "fixed light source + fixed detection base" structural design: to improve the contrast between colonies and culture medium, the light source is often tilted and positioned on both sides inside the detection chamber (e.g., LED lights are fixed on both sides of the upper part of the chamber), while the detection base is fixedly installed at the lower part of the chamber. The petri dishes are placed directly on the fixed base, and image acquisition and counting are completed by a high-resolution camera above. However, this design has significant technical shortcomings and cannot meet the requirements of food testing for "accuracy, comprehensiveness, and automation." Specific problems are as follows:

[0004] Fixed light sources cannot achieve multi-angle imaging and have detection blind spots and shadow interference: food colony morphology is diverse, and the agar in the petri dish may be slightly tilted due to the solidification process. Fixed light sources on both sides can only illuminate from a fixed angle. On the one hand, the edge area of ​​the petri dish and the tilted part of the agar are prone to forming "light blind spots", which prevent edge colonies from being captured by the camera. On the other hand, raised colonies or small impurities in the petri dish will produce local shadows under fixed lighting. Small colonies in the shadowed area are easy to miss, especially for small colonies with a diameter of <0.5mm, the false negative rate can reach more than 15%, which seriously affects the accuracy of the test results.

[0005] Therefore, it is essential to invent a colony counter for food quality testing. Utility Model Content

[0006] To address the aforementioned technical problems, this utility model provides a colony counter for food quality testing, comprising a testing chamber, a dynamic testing base, a rotating tray, an integrated controller, a bracket, an LED light source, a high-resolution camera, and a front baffle. The rotating tray is mounted on the dynamic testing base, which is fixedly installed at the bottom inside the testing chamber. The integrated controller is fixedly installed outside the testing chamber, controlling the dynamic testing base, the LED light source, and the high-resolution camera. LED light sources are fixedly installed on both sides of the upper inside of the testing chamber via the bracket. The high-resolution camera is fixedly installed in the middle of the upper inside of the testing chamber. The front baffle is fixedly installed in the upper inside of the testing chamber.

[0007] Preferably, the dynamic detection base includes a base, a servo motor, a drive shaft, a cavity, a photoelectric sensor, an electromagnetic slide, an electromagnet, and a trigger block. The base is fixedly installed inside the lower part of the detection box. The servo motor is embedded inside the lower part of the base. The output end of the servo motor is fixedly connected to the rotating tray through the drive shaft. An electromagnetic slide is installed at the cavity position of the drive shaft on the base. Six photoelectric sensors are fixedly installed on the inner wall of the cavity on the base. An electromagnet is fixedly installed inside the electromagnetic slide, and the trigger block is slidably installed thereon.

[0008] Preferably, the drive shaft is rotatably mounted on the base, with its lower end fixed to the output end of the servo motor and its upper end extending outward and fixedly connected to the lower surface of an externally mounted rotating storage tray, which is located above and outside the base.

[0009] Preferably, a cavity is provided inside the upper part of the base, and six photoelectric sensors are arranged at equal intervals on its inner wall. The integrated controller can control the high-resolution camera head by receiving signals from the photoelectric sensors, and the photoelectric sensors can detect the protruding trigger block.

[0010] Preferably, the trigger block is slidably mounted in the groove of the electromagnetic slide block, and the electromagnet is embedded in the groove of the electromagnetic slide block, the electromagnet being able to attract or repel the trigger block.

[0011] Preferably, the extended trigger block is detected by each of the photoelectric sensors, i.e., the high-resolution camera is controlled by the integrated controller to take pictures of the culture dish placed directly above the rotating tray.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] This utility model adopts a combination design of "two-sided tilted fixed LED light source + dynamic detection base (including rotating tray)" - the two-sided LED light source provides a stable lateral lighting foundation, and the servo motor drives the rotating tray to rotate the culture dish at a uniform speed of 360°, so that the colonies in different positions in the culture dish (including the edge area and the colonies at the tilt of the agar) can be illuminated by the light source from multiple angles, completely eliminating the "light blind zone" under the fixed light source.

[0014] Meanwhile, the position of the shadow of the colony changes dynamically with the rotation of the rotating tray of this utility model. The multi-frame images captured by the high-resolution camera can cover the clear shape of the colony without shadows, effectively avoiding the problem of missed detection caused by shadows caused by raised colonies and tiny impurities. According to actual tests, the recognition rate of tiny colonies with a diameter of <0.5mm and transparent colonies is increased to over 98%, and the detection accuracy is significantly better than that of traditional fixed light source equipment.

[0015] In this utility model of dynamic detection base, the electromagnet inside the electromagnetic slide controls the extension or retraction of the trigger block through "adsorption / repulsion". When the trigger block rotates with the drive shaft (rotating synchronously with the rotating placement plate) to the photoelectric sensor on the inner wall of the cavity, the photoelectric sensor transmits the signal to the integrated controller, thereby accurately triggering the high-resolution camera to take pictures. Six photoelectric sensors are equidistantly arranged on the inner wall of the cavity (one every 60°), ensuring that the angle interval of each picture is completely consistent. This avoids the angle deviation caused by the fluctuation of motor speed in traditional "timed triggering", and also eliminates the need for manual adjustment of the petri dish angle. It achieves "accurate imaging of 6 angles with one placement of the petri dish", greatly improving the standardization of detection conditions and reducing the detection error between samples to within 5%. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the internal structure of this utility model.

[0017] Figure 2 This is a front view diagram of the front baffle of this utility model before it is installed.

[0018] Figure 3 This is a partial cross-sectional structural diagram of the dynamic detection base of this utility model.

[0019] Figure 4 This is a utility model Figure 3 A magnified schematic diagram of the structure at point A.

[0020] In the picture:

[0021] Detection box 1, dynamic detection base 2, base 21, servo motor 22, drive shaft 23, cavity 24, photoelectric sensor 25, electromagnetic slide 26, electromagnet 27, trigger block 28, rotating tray 3, integrated controller 4, bracket 5, LED light source 6, high resolution camera 7, front baffle 8. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0023] In the description of the embodiments, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the present invention and for 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. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In the description of the utility model, it should be noted that unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in the present utility model based on the specific circumstances.

[0024] As attached Figure 1 To be continued Figure 4 As shown:

[0025] This utility model provides a colony counter for food quality testing, comprising a testing box 1, a dynamic testing base 2, a rotating tray 3, an integrated controller 4, a bracket 5, an LED light source 6, a high-resolution camera 7, and a front baffle 8. The rotating tray 3 is mounted on the dynamic testing base 2, which is fixedly installed inside the testing box 1 at the bottom. The integrated controller 4 is fixedly installed outside the testing box 1, controlling the dynamic testing base 2, the LED light source 6, and the high-resolution camera 7. The LED light sources 6 are fixedly installed on both sides of the upper part of the testing box 1 via the bracket 5. The high-resolution camera 7 is fixedly installed in the middle of the upper part of the testing box 1. The front baffle 8 is fixedly installed in the upper part of the testing box 1.

[0026] Furthermore, the dynamic detection base 2 includes a base 21, a servo motor 22, a drive shaft 23, a cavity 24, a photoelectric sensor 25, an electromagnetic slide 26, an electromagnet 27, and a trigger block 28. The base 21 is made of high-strength aluminum alloy (model 6061-T6) and is fixedly connected to the preset mounting holes at the bottom of the detection box 1 using M5 hexagonal bolts. The mounting cavity inside the base 21 is used to embed the servo motor 22 (a 42-step servo motor is selected to meet the load requirements of the petri dish + rotating tray 3). The servo motor 22 is fixed to the inner wall of the base 21 by an interference fit through a motor bracket, and the motor output shaft is rigidly connected to the lower end of the drive shaft 23 through a flexible coupling. The shaft of the drive shaft 23 corresponds to the position of the cavity 24 set in the base 21, and the electromagnetic slide 26 (the electromagnetic slide 26 is made of engineering plastic and has a built-in T-shaped groove) is fitted with it by an interference fit. A cylindrical cavity 24 is opened at the top inside the cavity. Six sensor mounting slots (0°, 60°, 120°, 180°, 240°, and 300°) are equally spaced along the circumference of the inner wall of the cavity 24. Each mounting slot is fixed with an M3 screw to install a photoelectric sensor 25 (a diffuse reflection photoelectric sensor, model E3Z-D61, with a detection distance of 5-10mm). An electromagnet 27 (DC 12V electromagnet, 10N attraction force) is embedded in the center of the electromagnetic slide 26. A trigger block 28 is slidably mounted in the T-shaped slide groove outside the electromagnet 27. The trigger block 28 can extend or retract along the axial direction of the slide groove. The overall structure ensures that when the servo motor 22 drives the drive shaft 23 to rotate, the electromagnetic slide 26 and the trigger block 28 can rotate synchronously with the drive shaft 23 in the cavity 24. At the same time, the photoelectric sensor 25 can stably detect the position signal of the trigger block 28.

[0027] Furthermore, the drive shaft 23 adopts a segmented structure design. Its middle section is rotatably connected to the bearing housing of the base 21 via two deep groove ball bearings (model 6204). The bearing housing and base 21 are integrally formed, and the outer ring of the bearing is fixed by a retaining ring. The lower end of the drive shaft 23 passes through the lower cavity of the base 21 and is connected to the output shaft of the servo motor 22 via a flexible coupling (polyurethane material). This coupling can buffer the impact torque during motor startup and prevent the drive shaft 23 from deforming due to excessive instantaneous force. The upper end of the drive shaft 23 passes through a shaft hole at the top of the base 21. It extends to the outside of the base 21 and its top end is fixedly connected to the pre-set threaded hole on the lower surface of the rotating tray 3 by an M4 hexagonal screw; the diameter of the rotating tray 3 is 20mm larger than that of a standard petri dish (90mm diameter), and the surface of the tray is provided with annular anti-slip ridges (ridge height 0.5mm) to prevent the petri dish from sliding and shifting when the rotating tray 3 rotates, and the distance between the upper surface of the rotating tray 3 and the top of the base 21 is set to 15mm to leave enough space to avoid friction interference with the base 21 when rotating.

[0028] Furthermore, the cylindrical cavity 24 located above the base 21 has its axis coincident with the axis of the drive shaft 23. Six photoelectric sensors 25 on the inner wall of the cavity 24 are equidistantly distributed along the circumference (the center angle between adjacent sensors is 60°), and the detection direction of all photoelectric sensors 25 points to the central axis of the cavity 24 (i.e., the movement trajectory of the trigger block 28). The signal output terminal of each photoelectric sensor 25 is electrically connected to the signal input terminal of the integrated controller 4 (using an STM32F103 microcontroller as the core control chip) through a shielded wire (model RVVP2×0.5). The shielded wire passes through a pre-set wiring groove on the inner wall of the base 21. To avoid the wires getting tangled and affecting the rotation of the drive shaft 23, the detection threshold of the photoelectric sensor 25 is preset by the integrated controller 4. The sensor only outputs a high-level signal when the trigger block 28 extends to a distance of 5-8mm from the sensor probe (it outputs a low level when the trigger block 28 is not detected), ensuring the accuracy of signal detection. At the same time, the integrated controller 4 has a pre-stored logic program that can receive signals from the 6 photoelectric sensors 25 in real time and determine the current rotation angle of the rotating tray 3 according to the signal source (i.e., sensors at different angles), thereby accurately controlling the timing of the high-resolution camera 7 to take pictures and achieve the linkage effect of "angle-corresponding shooting".

[0029] Furthermore, the trigger block 28 is made of soft iron (possessing good magnetic conductivity, which can be effectively attracted by the electromagnet 27), and its shape is T-shaped (matching the T-shaped groove of the electromagnetic slide block 26). The protruding end of the trigger block 28 is machined into an arc surface (to avoid collision with the inner wall of the cavity 24 during rotation), and the surface of the trigger block 28 is galvanized to prevent rusting. The inner wall of the T-shaped groove of the electromagnetic slide block 26 is coated with polytetrafluoroethylene. The electromagnet 27 is embedded in the bottom of the T-shaped groove of the electromagnetic slide block 26. The power input terminal of the electromagnet 27 is connected to the power supply of the integrated controller 4 through a slip ring (installed on the shaft of the drive shaft 23, model MRH-30). The output terminal is electrically connected (the slip ring enables untangled power supply to the drive shaft 23 when it rotates); the integrated controller 4 controls the electromagnet 27 to generate an "attractive" or "repulsive" magnetic field by changing the direction of the power supply current to the electromagnet 27: when the current is input in the positive direction, the electromagnet 27 generates an attractive magnetic field, attracting the trigger block 28 to the bottom of the slide (in the retracted state, not entering the detection range of the photoelectric sensor 25); when the current is input in the reverse direction, the electromagnet 27 generates a repulsive magnetic field, pushing the trigger block 28 to extend along the slide (the extension length is 10mm, just entering the detection range of the photoelectric sensor 25), thus realizing the extension and retraction control of the trigger block 28.

[0030] Furthermore, after the device is started, the integrated controller 4 first controls the electromagnet 27 to be energized in reverse, pushing the trigger block 28 to extend to the detection position. Simultaneously, it controls the servo motor 22 to start, driving the drive shaft 23, the rotating tray 3, and the trigger block 28 to rotate clockwise at a uniform speed (60° / second). When the trigger block 28 rotates with the drive shaft 23 into the detection range of the first photoelectric sensor 25, the sensor outputs a high-level signal to the integrated controller 4. Upon receiving the signal, the controller immediately delays for 0.1 seconds (the delay time is used to compensate for mechanical vibration and avoid image blurring) to control the high-resolution camera 7 (using a 5-megapixel industrial camera with an 8mm lens focal length) to start taking pictures, capturing an image of the colonies on the culture dish above the rotating tray 3 at the current angle. Subsequently, The trigger block 28 continues to rotate with the drive shaft 23. Every 60° rotation (i.e., triggering the next photoelectric sensor 25), the integrated controller 4 repeats the action of "receiving signal → delaying → controlling the taking picture" until all 6 photoelectric sensors 25 detect the trigger block 28 and complete 6 pictures (covering the entire 360° angle of the petri dish). After the 6 pictures are completed, the integrated controller 4 immediately controls the electromagnet 27 to be energized in the forward direction, attracting the trigger block 28 back to the bottom of the chute. At the same time, it controls the servo motor 22 to stop rotating, completing the taking picture action of one detection cycle. The entire linkage process does not require manual intervention, and the angle interval of the 6 pictures is accurate (error ≤ 1°), ensuring that areas such as the edges and corners of the petri dish that are prone to blind spots can be clearly captured, improving the integrity of colony counting.

[0031] The working principle is as follows: First, the operator places the cultured food colony detection petri dish on the rotating tray 3, closes the door of the detection box 1 (installed by a sealed hinge), and then starts the equipment. The entire detection process is automatically controlled by the integrated controller 4.

[0032] Next, the integrated controller 4 first performs an initialization action: on the one hand, it controls the electromagnet 27 to be energized in reverse, so that the electromagnet 27 generates a repulsive magnetic field, pushing the trigger block 28 to extend along the slide groove of the electromagnetic slide block 26 to the preset detection position; on the other hand, it simultaneously turns on the LED light sources 6 on both sides of the upper part of the detection box 1 to provide stable and uniform illumination for the colonies on the surface of the culture dish, ensuring the clarity of subsequent image acquisition.

[0033] Subsequently, the integrated controller 4 sends a start signal to the servo motor 22, and the servo motor 22 starts to run and drives the drive shaft 23 to rotate. Since the drive shaft 23 is fixedly connected to the rotating tray 3 and the electromagnetic slide 26, the rotating tray 3 (and the petri dish above it), the electromagnetic slide 26 (and the extended trigger block 28) will rotate synchronously and uniformly with the drive shaft 23.

[0034] When the trigger block 28 gradually approaches the first photoelectric sensor 25 on the inner wall of the cavity 24 of the base 21 as it rotates, the photoelectric sensor 25 detects the trigger block 28 and transmits a high-level signal to the integrated controller 4. After receiving the signal, the integrated controller 4 will delay for a very short time to cancel the slight vibration caused by the mechanical rotation (to avoid image blurring), and then immediately control the high-resolution camera 7 in the middle of the upper part of the detection box 1 to start and collect a colony image of the culture dish on the rotating tray 3 directly below.

[0035] Afterwards, the trigger block 28 continues to rotate with the drive shaft 23. Every time it rotates a certain angle (corresponding to the interval angle between adjacent photoelectric sensors 25), it will be detected by the next photoelectric sensor 25. The photoelectric sensor 25 repeatedly transmits signals to the integrated controller 4, and the integrated controller 4 repeats the action of "receiving signals → delaying → controlling the high-resolution camera 7 to take pictures" until the trigger block 28 triggers all six photoelectric sensors 25 on the inner wall of the cavity 24 in sequence. The high-resolution camera 7 completes six image acquisitions from different angles (covering the entire 360° area of ​​the culture dish and eliminating detection blind spots).

[0036] Finally, after the sixth photo is taken, the integrated controller 4 immediately adjusts the direction of the power supply current of the electromagnet 27, so that the electromagnet 27 switches to an adsorption magnetic field, attracting the trigger block 28 to the bottom of the groove of the electromagnetic slide block 26 (retracting the trigger block 28 so that it is out of the detection range of the photoelectric sensor 25); at the same time, a stop signal is sent to the servo motor 22, the servo motor 22 stops running, the rotating tray 3 and the drive shaft 23 stop rotating, and the LED light source 6 is also turned off synchronously. Thus, the image acquisition process of one food colony detection (i.e., the core workflow of the colony counter) is completed. Subsequently, the six sets of images acquired can be processed by the supporting image analysis system to finally count the number of colonies in the petri dish.

[0037] Any technical solution that achieves the above-mentioned technical effects by utilizing the technical solution described in this utility model, or by designing a similar technical solution inspired by the technical solution described in this utility model, falls within the protection scope of this utility model.

Claims

1. A colony counter for food quality testing, characterized in that, The device includes a detection box (1), a dynamic detection base (2), a rotating tray (3), an integrated controller (4), a bracket (5), an LED light source (6), a high-resolution camera (7), and a front baffle (8). The rotating tray (3) is mounted on the dynamic detection base (2) fixedly installed inside the detection box (1). The integrated controller (4) is fixedly installed outside the detection box (1), which controls the dynamic detection base (2), the LED light source (6), and the high-resolution camera (7). The LED light source (6) is fixedly installed on both sides of the upper part of the detection box (1) through the bracket (5). The high-resolution camera (7) is fixedly installed in the middle of the upper part of the detection box (1). The front baffle (8) is fixedly installed in the upper part of the detection box (1). The dynamic detection base (2) contains... The system includes a base (21), a servo motor (22), a drive shaft (23), a cavity (24), a photoelectric sensor (25), an electromagnetic slide (26), an electromagnet (27), and a trigger block (28). The base (21) is fixedly installed inside the lower part of the detection box (1). The servo motor (22) is embedded inside the lower part of the base (21). The output end of the servo motor (22) is fixedly connected to the rotating tray (3) through the drive shaft (23). The electromagnetic slide (26) is installed at the position of the cavity (24) set in the base (21). Six photoelectric sensors (25) are fixedly installed on the inner wall of the cavity (24) set in the base (21). An electromagnet (27) is fixedly installed inside the electromagnetic slide (26), and the trigger block (28) is slidably installed thereon.

2. The colony counter for food quality testing as described in claim 1, characterized in that: The drive shaft (23) is rotatably mounted on the base (21), with its lower end fixed to the output end of the servo motor (22) and its upper end extending outwards, and fixedly connected to the lower surface of the externally mounted rotating storage tray (3). The rotating storage tray (3) is located above the outside of the base (21).

3. A colony counter for food quality testing as described in claim 2, characterized in that: The base (21) has a cavity (24) located above the interior, and six photoelectric sensors (25) are arranged at equal intervals on its inner wall. The integrated controller (4) can control the high-resolution camera head (7) by receiving signals from the photoelectric sensors (25). The photoelectric sensors (25) can detect the trigger block (28) protruding outward.

4. A colony counter for food quality testing as described in claim 3, characterized in that: The trigger block (28) is slidably installed in the groove of the electromagnetic slide (26), and the electromagnet (27) is embedded in the groove of the electromagnetic slide (26). The electromagnet (27) can attract or repel the trigger block (28).

5. A colony counter for food quality testing as described in claim 4, characterized in that: The extended trigger block (28) is detected by each of the photoelectric sensors (25), that is, the high-resolution camera (7) is controlled by the integrated controller (4) to take pictures of the culture dish placed directly above the rotating tray (3).

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