Vision inspection counting device and method
By integrating an angle sensor and a vision detector into a sensing module, and combining intelligent correction and threshold adjustment with a control module, the efficiency and accuracy issues of vision inspection equipment when inspecting Lego-like parts have been solved, achieving a highly efficient inspection process.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANTOU CITY GOODERS PRECISION TECHNOLOGY CO LTD
- Filing Date
- 2026-06-17
- Publication Date
- 2026-07-21
AI Technical Summary
Existing visual inspection equipment struggles to balance inspection efficiency and accuracy when inspecting small parts such as Lego-like plastic building blocks. In particular, the large differences in the shape and size of the parts make angle correction time-consuming and inefficient.
The sensing module, which integrates an angle sensor and a vision detector, monitors the tilt angle and length and width data of the parts in real time through the control module. It automatically corrects and judges the qualification of the parts. When the tilt angle exceeds the threshold, an alarm is issued or the parts are put back into the material pool. The aspect ratio is adjusted to deduce the tilt angle in reverse. The threshold is dynamically adjusted to adapt to the inspection requirements of parts with different shapes.
It improves the accuracy and efficiency of inspection, reduces false positives, ensures the continuity of the production line and the rapid rejection of abnormal parts, and adapts to the inspection needs of parts with different shapes.
Smart Images
Figure CN122425007A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of visual inspection technology, specifically relating to a visual inspection counting device and method. Background Technology
[0002] Generally, after a product is manufactured, it needs to be inspected to ensure its yield and remove defective products. Traditional manual inspection methods are time-consuming and labor-intensive, while automatic visual inspection methods are more efficient and are becoming the common solution.
[0003] After toy production and processing, the finished toys are conveyed to the subsequent quality inspection area via a conveyor belt. Due to rotation or displacement during transport, data errors can occur during subsequent testing, compromising the quality of the toys. Furthermore, existing testing methods are inefficient. To address this, Chinese Patent CN116465895A discloses an automatic positioning visual inspection device and method, relating to the field of visual inspection equipment technology. This automatic positioning visual inspection device includes a base plate. A base frame is fixedly connected to one side of the top center of the base plate. A plurality of electrically operated telescopic rods are fixedly connected at equal intervals to the top center of the base frame. Each of the two electric telescopic rods has a connecting seat fixedly connected to its top. One side of each connecting seat is fixedly connected to the upper middle part of the outer wall of a corresponding inspection sleeve. Before visual inspection, the toy products on the inspection stand are first centered and then fine-tuned at their angles. This process of centering and fine-tuning the toy products improves the accuracy of visual inspection.
[0004] However, for toys such as Lego bricks, which are small in size but numerous in number, fine-tuning the angle of each part would be time-consuming. Furthermore, the shapes and sizes of these parts vary greatly. If the angle of each part were to be corrected individually, a large number of specialized molds would be required. Therefore, the above-mentioned solutions cannot achieve both efficiency and offsetting the influence of angle in such cases. For this reason, a visual inspection and counting device and method that can reduce the influence of angle while ensuring inspection accuracy is needed. Summary of the Invention
[0005] To address the aforementioned problems in the prior art, this invention provides a visual inspection and counting device and method that balances detection efficiency with guaranteed detection accuracy.
[0006] The objective of this invention can be achieved through the following technical solutions: A visual inspection and counting device includes a control module, a transmission module, and a sensing module. The transmission module is used to transport the parts to be inspected sequentially from the material pool and stop them at the inspection station. The sensing module is aligned with the inspection station. The transmission module and the sensing module are electrically connected to the control module. The sensing module includes an angle sensor and a vision detector, which are aligned with the inspection station. The angle sensor monitors the tilt angle of the part to be inspected and uploads the tilt angle data to the control module. The vision detector measures the length and width data of the part and uploads the length and width data to the control module. The control module determines whether the tilt angle data exceeds a first threshold. If the tilt angle is below the first threshold, it determines whether the length and width data are qualified. If the tilt angle exceeds the first threshold, it corrects the length and width data and determines whether the corrected length and width data are qualified. If the tilt angle data exceeds a second threshold, it issues an alarm and instructs the transmission module to put the part to be inspected back into the material pool.
[0007] As a preferred technical solution of the present invention, after receiving the length and width data, the control module calculates the length-to-width ratio of the current part and determines whether the length-to-width ratio meets the standard value. If the determination result is negative, the control module corrects the oblique angle data according to the ratio of the length-to-width ratio to the standard value.
[0008] As a preferred technical solution of the present invention, after receiving the length and width data, the control module calculates the length-to-width ratio C of the current part, and the control module corrects the tilt angle data to X times the original value, where X = C / C0 × d, where C0 is the standard value of the length-to-width ratio and d is the pre-input correction coefficient.
[0009] As a preferred embodiment of the present invention, the control module determines whether the current aspect ratio standard value exceeds the third threshold. When the aspect ratio is lower than the third threshold, the control module increases the value of the first threshold, and when the aspect ratio is higher than the third threshold, the control module decreases the value of the first threshold.
[0010] As a preferred embodiment of the present invention, the control module corrects the first threshold to Y times the original value, where Y = Z3 / C0 × e, Z3 is the pre-input third threshold, and e is the pre-input correction coefficient.
[0011] As a preferred embodiment of the present invention, it also includes a control panel, which is used to display the image uploaded by the visual detector, the tilt angle and length and width data of the current object to be inspected, and the control panel is used to input the values of C0, Z3, d and e.
[0012] The present invention also includes a method for a visual detection and counting device, applicable to the aforementioned visual detection and counting device, characterized by comprising the following steps: Step 1: Input the standard size, the first threshold, and the second threshold; Step 2: The conveyor module transports the parts to be inspected and places them at the inspection station; Step 3: The vision detector measures the length and width data of the part and uploads the data to the control module. The angle sensor monitors the tilt angle of the part and uploads the tilt angle data to the control module. The control module checks whether the tilt angle data exceeds the first threshold. If the result is no, proceed to step 4; otherwise, proceed to step 5. Step 4: The control module determines whether the length and width data are qualified. If the data is qualified, the instruction transmission module continues to run; if the data is unqualified, an alarm is issued. Step 5: The control module determines whether the tilt angle exceeds the second threshold. If the result is yes, proceed to step 6; otherwise, proceed to step 7. Step 6: The control module corrects the length and width data and determines whether the corrected length and width data are qualified. If the data is qualified, the instruction transmission module continues to run; if the data is unqualified, an alarm is issued. Step 7: The control module issues an alarm and instructs the transmission module to put the part to be tested back into the material pool.
[0013] The beneficial effects of this invention are as follows: (1) By integrating an angle detector near the inspection station, when the tilt angle data exceeds the first threshold, it means that the tilt angle of the part to be inspected exceeds the first threshold, which may cause a significant change in the projection size on the visual detector and affect the inspection accuracy. The length and width data are corrected and it is judged whether the corrected length and width data are qualified. This reduces the impact of the tilt angle on the inspection while taking into account the inspection efficiency. (2) When the tilt angle data exceeds the second threshold, indicating that the tilt angle is too large to be corrected, the control module issues an alarm and instructs the transmission module to put the workpiece to be tested back into the material pool, so that the sensing module can directly detect the next workpiece to be tested, and quickly complete the rejection of abnormal workpieces and the recovery of the detection line. (3) After receiving the length and width data, the control module calculates the length and width ratio of the current part and judges whether the length and width ratio meets the standard value. When the judgment result is no, the control module corrects the tilt angle data according to the ratio of the length and width ratio to the standard value. In the scenario where the angle sensor can detect the tilt direction of small parts but often cannot accurately measure the tilt angle, the size of the tilt angle is deduced in reverse by the change in the length and width ratio caused by the tilt angle, which further reduces the impact of the tilt angle on the detection. (4) By having the control module determine whether the current aspect ratio standard value exceeds the third threshold, the control module raises the value of the first threshold when the aspect ratio is lower than the third threshold and lowers the value of the first threshold when the aspect ratio is higher than the third threshold, thus completing the threshold adjustment based on the target aspect ratio. For parts with similar length and width and a shape closer to a cube, the judgment standard is lowered to avoid misjudgment. For parts with a large aspect ratio and a shape closer to a strip, the judgment standard is raised. Attached Figure Description
[0014] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.
[0015] Figure 1 This is a topology diagram of the modules in this invention. Detailed Implementation
[0016] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided.
[0017] Please see Figure 1 A visual inspection and counting device includes at least a material pool for holding parts to be inspected, a transmission module for transporting parts, a sensing module for inspection, and a control module for overall control. The end of the transmission module away from the material pool is connected to the subsequent production line. The transmission module is responsible for taking the parts to be inspected out of the material pool one by one, passing them sequentially through the inspection station of the sensing module, and sending the parts to the production line after they pass the inspection. The production line then transports the parts to the next packaging process. The transmission module and the sensing module are electrically connected to the control module. The control module is pre-set with the standard dimensions of the target part, the first threshold, the second threshold, and other judgment parameters required for subsequent processing. In actual operation, when parts are taken out of the material pool and placed on the transmission module, due to the small size and varied shapes of the parts, it is difficult to ensure that each part can pass through the inspection station perfectly horizontally. When a part has a tilt angle, its projected length on the vision detector will deviate from its actual length. For example, if a long strip that is originally qualified is tilted, it will appear shorter in the image and will be misjudged as a defective product. Conversely, if a mixed part that is actually too long is tilted at a specific angle, it may also be misjudged as qualified. The traditional solution is to correct the posture of each part, but this will seriously affect the inspection efficiency. For a large batch of small parts such as Lego plastic building blocks, this is not feasible in terms of efficiency. To this end, both an angle sensor and a vision detector are integrated into the sensing module. Both are aligned with the inspection station. The angle sensor is used to monitor the tilt angle of the part to be inspected at the inspection station in real time and upload the tilt angle data to the control module. The vision detector is used to measure the length and width data of the part in the image and upload the length and width data to the control module. The control module is pre-input with a first threshold and a second threshold, wherein the first threshold is less than the second threshold. The control module first determines whether the received tilt angle data exceeds the first threshold. In this embodiment, the first threshold is a small angle value, such as 3 degrees or 5 degrees, which represents the critical value at which the tilt angle will have a non-negligible impact on the measurement accuracy without any compensation. When the judgment result is that the tilt angle is lower than the first threshold, it means that the part posture is close to horizontal and the projection distortion can be ignored. The control module directly judges whether the original length and width data measured by the vision detector matches the pre-stored standard size. If they match, it is judged as qualified and the transmission module is instructed to continue to transport the part forward to the production line. At the same time, the counter is incremented by a value. If they do not match, an alarm is issued and the rejection device is instructed to remove the part. When the judgment result is that the tilt angle exceeds the first threshold, it means that the tilt has significantly affected the measurement value. At this time, the control module corrects the projected length and width data measured by the vision detector according to the specific tilt angle value transmitted by the angle sensor and the trigonometric function relationship, and then reverses it back to the true size. Then it judges whether the corrected length and width data is qualified. If it is qualified, it is also allowed and counted. If it is not qualified, an alarm is issued and it is rejected. By integrating an angle detector near the inspection station, when the tilt angle data exceeds the first threshold, indicating that the tilt angle of the part to be inspected exceeds the first threshold, which may cause a significant change in the projected size on the vision detector and affect the inspection accuracy, the length and width data are corrected and it is judged whether the corrected length and width data are qualified. This reduces the impact of the tilt angle on the inspection while taking into account the inspection efficiency. Furthermore, for parts whose tilt angle exceeds the first threshold, the control module will further determine whether it exceeds the second threshold. The second threshold is an angle value larger than the first threshold, such as 15 degrees or 20 degrees. When the control module determines that the tilt angle data exceeds the second threshold, it means that the part has tilted to the point that even after mathematical correction, the measurement accuracy cannot be guaranteed. At this time, the control module directly issues an alarm and instructs the transmission module to put the part back into the material pool for subsequent re-queueing and inspection. This avoids misjudgment of severely tilted parts and allows the sensing module to immediately start inspecting the next part, thereby ensuring the inspection continuity of the entire production line. By having the control module issue an alarm and instruct the transmission module to re-enter the workpiece into the material pool when the tilt angle data exceeds the second threshold, indicating that the tilt angle is too large to be corrected, the sensing module can directly detect the next workpiece, quickly completing the rejection of abnormal workpieces and restoring the operation of the inspection line.
[0018] In the actual operation of Scheme 1, since angle sensors usually have limited accuracy, when used to measure small Lego-like parts, especially when the size of the parts is between a few millimeters and a few centimeters and the tilt direction is relatively complex, the angle sensor can often only roughly detect the tilt direction and it is difficult to output a reliable angle value accurately. This makes it difficult to accurately execute the step of "correcting the length and width data according to the angle value" in Scheme 1 in actual equipment. If an inaccurate tilt angle data is used directly for trigonometric function correction, it may introduce new errors. Therefore, after receiving the length and width data, the control module calculates the aspect ratio of the current part and determines whether the aspect ratio meets the standard value. If the result is no, the control module corrects the tilt angle data according to the ratio of the aspect ratio to the standard value. Specifically, after receiving the length and width data from the vision detector, the control module first calculates the aspect ratio of the current part. This aspect ratio is equal to the length measurement value of the part divided by the width measurement value. At the same time, the control module has a pre-stored standard aspect ratio of the part under test in a completely horizontal state. When the part is tilted, the actual measured aspect ratio will be less than the standard aspect ratio, and there is a definite mathematical relationship between the change in this ratio and the tilt angle. Therefore, the control module compares the currently measured aspect ratio with the standard aspect ratio. When the judgment result is that the two match, it means that the part posture is good and no correction is needed. When the judgment results are inconsistent, it indicates that the part is tilted. At this time, the control module derives an equivalent tilt angle correction coefficient based on the ratio of the aspect ratio to the standard value. Specifically, after receiving the length and width data, the control module calculates the aspect ratio C of the current part. The control module then corrects the tilt angle data to X times the original value, where X = C / C0 × d, where C0 is the standard value of the aspect ratio, and d is the pre-input correction coefficient. The correction coefficient d is an empirical value obtained by conducting a small number of experiments on the same batch of parts. After receiving the length and width data, the control module calculates the aspect ratio of the current part and determines whether the aspect ratio meets the standard value. If the result is negative, the control module corrects the tilt angle data based on the ratio of the aspect ratio to the standard value. This allows the tilt angle to be deduced from the aspect ratio change caused by the tilt angle in scenarios where angle sensors can detect the tilt direction of small parts but often cannot accurately measure the tilt angle. This further reduces the impact of the tilt angle on detection.
[0019] In actual production lines, the shapes of Lego-like plastic parts vary greatly. Some parts are close to cubes, such as a 1x1x1 cube with a length-to-width ratio close to 1:1. These parts are prone to slight random tilting due to swaying during transport on conveyor belts, and this random tilting often does not significantly affect their projected dimensions. Other parts are elongated, such as a 1x1x4 strip with a large length-to-width ratio. These parts are extremely sensitive to tilting; even a slight tilt of just a few degrees can cause changes in projected length that exceed tolerances. Therefore, if the same fixed first threshold is used for all shapes of parts, the fixed threshold may be too strict for square parts, causing many qualified parts with only slight random swaying to be sent to the correction process or even returned to the material pool, reducing inspection efficiency. On the other hand, for elongated parts, the fixed threshold may be too lenient, causing some parts with obvious measurement errors to be directly judged as qualified without correction, reducing inspection accuracy. Therefore, the control module determines whether the current aspect ratio standard value exceeds the third threshold. When the aspect ratio is lower than the third threshold, the control module increases the value of the first threshold, and when the aspect ratio is higher than the third threshold, the control module decreases the value of the first threshold. In this embodiment, the control module pre-determines whether the standard aspect ratio of the target part to be inspected exceeds a pre-set third threshold. This third threshold is an empirical value, such as 3:1, used to distinguish between "parts that are close to square" and "parts that are obviously slender". When the standard aspect ratio is lower than the third threshold, it means that the current part is close to square and has low sensitivity to tilt. Therefore, the control module automatically increases the value of the first threshold, so that a larger range of tilt angles is included in the "no correction required for direct judgment" range, thereby avoiding a large number of qualified parts being dragged down by unnecessary correction processes and maintaining high detection efficiency. When the standard aspect ratio is higher than the third threshold, it means that the current part is slender and has extremely high sensitivity to tilt. Therefore, the control module automatically decreases the value of the first threshold, so that even a very small tilt angle will trigger the correction process to ensure measurement accuracy. Specifically, the control module corrects the first threshold to Y times the original value, where Y = Z3 / C0 × e, Z3 is the pre-input third threshold, and e is the pre-input correction coefficient. By having the control module determine whether the current aspect ratio standard value exceeds the third threshold, the control module raises the value of the first threshold when the aspect ratio is lower than the third threshold and lowers the value of the first threshold when the aspect ratio is higher than the third threshold, thus completing the threshold adjustment based on the target aspect ratio. For parts with similar length and width and shapes closer to cubes, which are more susceptible to shaking due to random factors, the judgment standard is lowered to avoid misjudgment. For parts with larger aspect ratios and shapes closer to strips, which are less susceptible to shaking due to random factors, the judgment standard is raised.
[0020] To facilitate the use of the above functions by on-site operators, a control panel is also included. The control panel is electrically connected to the control module. The display screen can display the part image currently captured by the vision detector in real time, as well as the tilt angle data measured by the angle sensor and the length and width data measured by the vision detector. Operators can intuitively monitor the inspection process of each part through this control panel. In addition, the control panel also provides a parameter input interface. Operators can input the aforementioned standard aspect ratio C0, third threshold Z3, correction coefficient d, and correction coefficient e according to the specifications of the current batch of parts.
[0021] The present invention also includes a method for a visual detection and counting device, applicable to the aforementioned visual detection and counting device, characterized by comprising the following steps: Step 1: Input the standard size, the first threshold, and the second threshold; Step 2: The conveyor module transports the parts to be inspected and places them at the inspection station; Step 3: The vision detector measures the length and width data of the part and uploads the data to the control module. The angle sensor monitors the tilt angle of the part and uploads the tilt angle data to the control module. The control module determines whether the tilt angle data exceeds the first threshold. If the result is no, proceed to step 4; otherwise, proceed to step 5. Step 4: The control module determines whether the length and width data are qualified. If the data is qualified, the instruction transmission module continues to run; if the data is unqualified, an alarm is issued. Step 5: The control module determines whether the tilt angle exceeds the second threshold. If the result is no, proceed to step 6; otherwise, if the tilt angle data exceeds the second threshold, proceed to step 7. Step 6: The control module corrects the length and width data and determines whether the corrected length and width data are qualified. If the data is qualified, the instruction transmission module continues to run; if the data is unqualified, an alarm is issued. Step 7: The control module issues an alarm and instructs the transmission module to put the part to be tested back into the material pool.
[0022] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.
Claims
1. A visual inspection and counting device, characterized in that: It includes a control module, a transmission module, and a sensing module. The transmission module is used to transport the parts to be tested sequentially from the material pool and stop them at the testing station. The sensing module is aligned with the testing station. The transmission module and the sensing module are electrically connected to the control module respectively. The sensing module includes an angle sensor and a vision detector, which are aligned with the inspection station. The angle sensor monitors the tilt angle of the part to be inspected and uploads the tilt angle data to the control module. The vision detector measures the length and width data of the part and uploads the length and width data to the control module. The control module determines whether the tilt angle data exceeds a first threshold or a second threshold. If the tilt angle is below the first threshold, it determines whether the length and width data are qualified. If the tilt angle exceeds the first threshold, it corrects the length and width data and determines whether the corrected length and width data are qualified. If the tilt angle data exceeds the second threshold, it issues an alarm and instructs the transmission module to put the part to be inspected back into the material pool. The first threshold is less than the second threshold.
2. The visual inspection and counting device according to claim 1, characterized in that: After receiving the length and width data, the control module calculates the aspect ratio of the current part and determines whether the aspect ratio meets the standard value. If the result is negative, the control module corrects the angle data according to the ratio of the aspect ratio to the standard value.
3. The visual inspection and counting device according to claim 2, characterized in that: After receiving the length and width data, the control module calculates the aspect ratio C of the current part. The control module then corrects the tilt angle data to X times the original value, where X = C / C0 × d, and C0 is the standard aspect ratio value, and d is the pre-input correction coefficient.
4. The visual inspection and counting device according to claim 3, characterized in that: The control module determines whether the current aspect ratio standard value exceeds the third threshold. When the aspect ratio is lower than the third threshold, the control module increases the value of the first threshold, and when the aspect ratio is higher than the third threshold, the control module decreases the value of the first threshold.
5. The visual detection and counting device according to claim 4, characterized in that: The control module corrects the first threshold to Y times the original value, where Y = Z3 / C0 × e, Z3 is the pre-input third threshold, and e is the pre-input correction coefficient.
6. The visual detection and counting device according to claim 5, characterized in that: It also includes a control panel, which is used to display the images uploaded by the visual detector, the tilt angle and length and width data of the current object to be inspected, and the control panel is used to input the values of C0, Z3, d and e.
7. A method for a visual inspection and counting device, applicable to the visual inspection and counting device described in claims 1-6, characterized in that: Includes the following steps: Step 1: Input the standard size, the first threshold, and the second threshold; Step 2: The conveyor module transports the parts to be inspected and places them at the inspection station; Step 3: The vision detector measures the length and width data of the part and uploads the data to the control module. The angle sensor monitors the tilt angle of the part and uploads the tilt angle data to the control module. The control module checks whether the tilt angle data exceeds the first threshold. If the result is no, proceed to step 4; otherwise, proceed to step 5. Step 4: The control module determines whether the length and width data are qualified. If the data is qualified, the instruction transmission module continues to run; if the data is unqualified, an alarm is issued. Step 5: The control module determines whether the tilt angle exceeds the second threshold. If the result is no, proceed to step 6; otherwise, proceed to step 7. Step 6: The control module corrects the length and width data and determines whether the corrected length and width data are qualified. If the data is qualified, the instruction transmission module continues to run; if the data is unqualified, an alarm is issued. Step 7: The control module issues an alarm and instructs the transmission module to put the part to be tested back into the material pool.