Infrared imaging non-contact measurement method and device for liquid level of multi-material filling container

Abstract

This invention relates to an infrared imaging non-contact measurement method and apparatus for liquid level in multi-material filling containers. The measuring apparatus includes: a heating module comprising a heating area, wherein the heating module provides non-contact thermal excitation to the heating area, thereby creating a temperature gradient at the liquid level interface within the filling container located within the heating area; and an image acquisition module comprising an imaging area, wherein the image acquisition module acquires a temperature distribution image of the filling container containing liquid level characteristics within the imaging area, wherein the imaging area is located downstream of the heating area. Through the above configuration, this invention achieves high-precision, non-contact measurement of the liquid level interface inside the filling container.

Description

Technical Field

[0001] This invention relates to the field of liquid level measurement technology in liquid filling production lines, and in particular to an infrared imaging non-contact measurement method and device for liquid level in multi-material filling containers. Background Technology

[0002] In the food and beverage industry, during liquid filling, the height after filling needs to be calibrated to ensure volume consistency. In actual production, production lines frequently face product changes, such as different bottle types (plastic, glass, metal) and different filling liquids (juice, mineral water, beer, etc.). Existing contact-based or container-optimized testing methods inevitably suffer from long downtime for setup, hygiene risks associated with contact measurements, and poor adaptability to different materials, potentially leading to low production efficiency and testing failures.

[0003] To address the above problems, common technologies in the field of liquid level detection include: Machine vision inspection methods rely on the optical transparency of containers, which has inherent limitations for measuring liquid levels in bottles made of non-transparent materials. Laser ranging technology requires that the container be open and that the surface of the liquid being measured be relatively flat, which limits its applicability in actual industrial scenarios. Ultrasonic liquid level detection technology also faces multiple technical bottlenecks: First, the method is not effective for detecting high-viscosity media (such as oily liquids); Second, traditional ultrasonic sensors usually only have threshold detection function, that is, to determine whether the liquid level has reached the preset height. However, in flexible production lines, the change of filling products is often accompanied by dynamic adjustment of the target liquid level, and a single threshold detection mode is difficult to meet the production needs of multiple varieties and variable batches.

[0004] Therefore, there is a lack of a liquid level measurement device that can overcome the above-mentioned defects to meet the comprehensive requirements of modern filling production lines for multi-variety adaptability, high hygiene standards, high detection efficiency and high measurement accuracy. Summary of the Invention

[0005] To address the aforementioned shortcomings, this invention proposes an infrared imaging non-contact measurement method and device for liquid level in multi-material filling containers.

[0006] The technical solution adopted in this invention is an infrared imaging non-contact measurement device for liquid level in multi-material filling containers, comprising: A heating module includes a heating area, wherein the heating module applies non-contact thermal excitation to the heating area, thereby creating a temperature gradient at the liquid level interface in the filling container located within the heating area. An image acquisition module includes an imaging area, which acquires a temperature distribution image containing liquid level characteristics of a filling container within the imaging area, wherein the imaging area is located downstream of the heating area.

[0007] Preferably, the heating module further includes a heat flow control component located on one side of the heating area. The heat flow control component integrates a radiation element and / or a convection duct. The heat flow control component provides non-contact thermal stimulation to the heating area through gas convection and / or radiation.

[0008] Preferably, the heating module further includes a thermal resistance plate, the area between the thermal resistance plate and the heat flow control component is the heating area, and the thermal resistance plate is made of polytetrafluoroethylene.

[0009] Preferably, the image acquisition module further includes an infrared detector located on one side of the imaging area, with a narrow-band filter provided on the optical path of the infrared detector, and the infrared detector acquires a temperature distribution image containing liquid level characteristics of the filling container in the imaging area through the narrow-band filter.

[0010] Preferably, the image acquisition module further includes a radiation panel, and the area between the radiation panel and the infrared detector is the imaging area; the material of the radiation panel is zinc sulfide, and / or the temperature of the radiation panel is controlled at a preset temperature, which is 8°C to 15°C higher than the ambient temperature.

[0011] Preferably, the system further includes a visual recognition module located upstream of the heating zone. The visual recognition module acquires visible light images of the filling container and obtains at least one type of information about the filling container, including material and specifications.

[0012] Preferably, the system further includes an image processing module, which processes and / or analyzes the temperature distribution image based on the type information of the filling container, and obtains the liquid level measurement result of the filling container.

[0013] Preferably, the system also includes an incoming material sensing module located upstream of the visual recognition module. The incoming material sensing module includes a laser emitter and a laser receiver arranged opposite to each other. The output signal of the incoming material sensing module is used to trigger the start-up of the heating module and the image acquisition module.

[0014] This invention also discloses an infrared imaging non-contact measurement method for liquid level in multi-material filling containers, employing the aforementioned infrared imaging non-contact measurement device for liquid level in multi-material filling containers, comprising the following steps: S100: The arrival of the filling container is detected through non-contact sensing, triggering the measurement process; S200: Acquire a visible light image of the filling container and identify the material and specifications of the filling container; S300. Apply non-contact thermal excitation to the filling container to form a temperature gradient at the liquid level interface of the filling container. S400. Under controlled thermal background conditions, acquire a temperature distribution image of the filling container after thermal excitation; S500. Based on the material and specifications of the filling container, process the temperature distribution image, extract and determine the liquid level information inside the filling container.

[0015] Preferably, the controlled thermal background condition is a constant state in which the background radiation temperature is 8°C-15°C higher than the ambient temperature.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The entire measurement process is completely non-contact, and the measuring element does not need to have any physical contact with the container or liquid, which fundamentally eliminates the risk of cross-contamination and avoids problems such as corrosion and scaling that may occur when the measuring element comes into contact with liquid. It is particularly suitable for filling production lines with extremely high hygiene requirements, such as food and pharmaceuticals, while reducing equipment maintenance costs and improving the reliability and stability of system operation.

[0017] 2. The infrared imaging non-contact measurement device for liquid level in multi-material filling containers relies on infrared thermal radiation imaging. Its effectiveness is not limited by the optical transparency of the container material. Whether it is transparent glass, translucent plastic, or opaque metal or ceramic container, as long as the material can conduct heat and exhibit certain infrared radiation characteristics, it can be applied, thus achieving multi-material adaptability.

[0018] 3. Based on the analysis of temperature distribution images, the system can obtain continuous liquid level height information, rather than a simple threshold judgment, thereby eliminating the measurement blind spot present in discrete detection methods, significantly improving the integrity and accuracy of measurement, and meeting the refined requirements of dynamic adjustment of liquid level standards in flexible production.

[0019] 4. The device is based on the physical principles of infrared thermal imaging and thermal excitation. Its detection effect is not affected by the viscosity of the liquid and it is also applicable to high-viscosity media (such as oily liquids). It has high detection efficiency and significant cost-effectiveness. At the same time, the method does not require the container to be open or has special requirements for the flatness of the liquid surface. Therefore, it has significant applicability and a wide range of applications in complex and ever-changing actual industrial scenarios.

[0020] 5. By precisely configuring the thermal resistance plate and the heat flow control component, this embodiment physically constructs a constrained heat flow field. Utilizing the inertia and thermal stability of the polytetrafluoroethylene (PTFE) thermal resistance plate, it is precisely positioned opposite the hot air micro-heating device, reducing heat loss, improving signal contrast, optimizing heating efficiency, and ensuring temperature measurement accuracy. It can create a stable temperature gradient at the liquid level interface, achieving high-precision, non-invasive thermal excitation without affecting the main liquid temperature. Attached Figure Description

[0021] The present invention will now be described in detail with reference to the embodiments and accompanying drawings, wherein: Figure 1 This is a schematic diagram of an infrared imaging non-contact measurement device for liquid level in multi-material filling containers. Figure 2 This is a front view of an infrared imaging non-contact measuring device for liquid levels in multi-material filling containers; Figure 3 This is a side view of an infrared imaging non-contact measuring device for liquid levels in multi-material filling containers; Figure 4 This is a top view of an infrared imaging non-contact measurement device for liquid levels in multi-material filling containers.

[0022] 1. Conveying module; 2. Thermal resistance plate; 3. Radiation panel; 4. Operating console; 5. Connecting bracket one; 6. Image acquisition module; 7. Heat flow control component; 8. Connecting bracket two; 9. Visual recognition module; 10. Incoming material sensing module. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0024] In one embodiment, see Figure 1 This invention provides an infrared imaging non-contact measurement device for liquid levels in multi-material filling containers, which can be used for accurate liquid level identification during liquid filling production in the food and beverage industry. The core concept of this device lies in spatially separating and temporally linking the two key processes of thermal excitation and infrared imaging through a sequential and modular physical layout, thereby achieving high-precision, non-contact measurement of the liquid level interface inside the filling container.

[0025] The device mainly comprises two functional units: a heating module and an image acquisition module. The heating module defines a specific heating zone on the production line. Its core function is to apply a controllable and uniform thermal excitation to the filling containers passing through this zone in a non-contact manner, causing the air cavity gas and the filled liquid inside the container to heat up in the same uniform thermal field. The physical mechanism utilizes the inherent thermophysical property differences between the filled liquid inside the container and the air cavity above it, especially the significant difference in their specific heat capacities. When the container is subjected to external thermal excitation, the gas region with a relatively smaller specific heat capacity responds rapidly and heats up quickly; while the liquid region with a larger specific heat capacity changes temperature relatively slowly. This difference in thermal response speed results in a detectable and clear small temperature gradient at the liquid-gas interface, i.e., the liquid level interface, creating a small but clear temperature difference on the bottle wall. Thermal excitation involves using a brief, weak, and controllable external heat source to stimulate the object being measured. The purpose of thermal excitation is not to drastically change the liquid temperature, but to utilize the different reaction rates of liquid and air to heat (difference in specific heat capacity) to create a small, instantaneous temperature difference at their interface.

[0026] Image acquisition module 6 defines an imaging region located downstream of the heating zone. The core component of this module is an infrared thermal imaging system, whose function is to capture a two-dimensional temperature distribution image of the surface of the filling container entering the imaging region. Due to the difference in thermal response characteristics between the liquid and gas phases after the upstream thermal excitation process, the liquid and air regions will exhibit different temperature distribution characteristics, thus forming a clearly discernible temperature gradient boundary line in the infrared thermal image. This boundary line highly coincides with the gas-liquid interface. Therefore, the acquired infrared image is essentially a temperature distribution image containing liquid level characteristics. In the image, pixels corresponding to the gas region above the liquid level and the liquid region below will exhibit different grayscale or color values, and the boundary line accurately reflects the physical liquid level height inside the container. Furthermore, by identifying and locating this thermal boundary through image processing, the precise extraction and quantification of the liquid level height can be achieved.

[0027] Through the above design, the device provided in this embodiment achieves several beneficial technical effects. First, the entire measurement process is completely non-contact; the measuring element does not need to have any physical contact with the container or liquid, fundamentally eliminating the risk of cross-contamination and avoiding problems such as corrosion and scaling that may occur when the measuring element comes into contact with the liquid. This makes it particularly suitable for filling production lines in industries with extremely high hygiene requirements, such as food and pharmaceuticals, while also reducing equipment maintenance costs and improving the reliability and stability of system operation. Second, this device relies on infrared thermal radiation imaging, and its effectiveness is not limited by the optical transparency of the container material. Whether it is transparent glass, translucent plastic, or opaque metal or ceramic containers, as long as the material can conduct heat and exhibit certain infrared radiation characteristics, it is applicable, thus achieving multi-material adaptability. Third, based on the analysis of the temperature distribution image, the system can obtain continuous liquid level height information, rather than a simple threshold judgment, thereby eliminating the measurement blind spots present in discrete detection methods, significantly improving the integrity and accuracy of the measurement, and meeting the refined requirements of dynamic adjustment of liquid level standards in flexible production. Finally, the device provided in this embodiment is based on the physical principles of infrared thermal imaging and thermal excitation. Its detection effect is not affected by the viscosity of the liquid and it is also applicable to high-viscosity media (such as oily liquids). It has high detection efficiency and significant cost-effectiveness. At the same time, the method does not require the container to be open or has special requirements for the flatness of the liquid surface. Therefore, it has significant applicability and a wide range of applications in complex and ever-changing actual industrial scenarios.

[0028] In one embodiment, see Figure 2 The heating module further includes a precision heat flow control component 7, which is configured on one side of the heating area. The heat flow control component 7 integrates a thermal excitation source, which can be implemented in various ways, including but not limited to infrared radiation elements or convection ducts, or a combination of both. Based on this structure, the heat flow control component 7 can provide non-contact thermal excitation to the filling container passing through the heating area by generating a controlled gas convection field and / or a directional infrared radiation field.

[0029] The core function of the heat flow control component 7 is to achieve precise and controllable energy transfer. When using convection, the component generates an airflow with precisely regulated temperature and velocity, which acts uniformly on the outer surface of the container. When using radiation, the component emits infrared radiation of a specific wavelength, which is effectively absorbed by the container wall material. Regardless of the excitation method used or its combination, the physical essence is to input a small amount of heat energy into the container through a non-contact process, achieving non-invasive adaptive differential thermal excitation for multi-material packaging products.

[0030] During thermal excitation, due to the intrinsic difference in specific heat capacity between the liquid inside the container and the gas in the cavity above it, the liquid portion heats up slowly, while the gas portion heats up rapidly. This significant difference in response speed creates a clear and stable axial temperature gradient at the liquid-gas interface, specifically in the container wall region near the liquid level. This temperature gradient forms the physical basis for subsequent infrared imaging detection.

[0031] Through the above design, the heating module in this embodiment achieves efficient, uniform, and controllable non-contact thermal excitation. It not only avoids physical contact with the container, meeting hygiene requirements, but more importantly, it provides a reliable guarantee for generating high-quality, high signal-to-noise ratio temperature gradient signals at the liquid level interface of containers of different materials and specifications, forming a key prerequisite for subsequent high-precision infrared imaging detection.

[0032] In one embodiment, the infrared radiation element in the heat flow control component 7 can more specifically be a carbon fiber infrared heating tube, a ceramic infrared emitter, or a quartz infrared lamp. When energized, the heating element (carbon fiber braid, ceramic body doped with metal oxides, or tungsten filament) generates high temperature due to resistance and radiates electromagnetic waves with peak wavelengths in the mid-to-far infrared band. This band matches well with the infrared absorption bands of most packaging materials (such as plastic and glass), enabling efficient penetration of the thin layer of air on the container surface and body heating of the bottle wall. Its power can be precisely controlled by adjusting the input voltage or using pulse width modulation to achieve fine-tuning of the thermal excitation intensity.

[0033] More specifically, the convection duct in the heat flow control component 7 may include a centrifugal fan or a vortex fan, a duct housing, and an electric heating unit, such as a heater or heating wire, built into the duct. The fan generates a forced airflow, which is heated to a preset temperature by the electric heating unit and then blown onto the container surface through a uniform flow field formed by the duct outlet. The duct outlet may be designed as a slit or an array of holes to ensure the uniformity of the lateral temperature in the heating area. By independently adjusting the fan speed and the heating unit power, coordinated control of the airflow temperature and velocity can be achieved, thereby adapting to the differentiated thermal excitation requirements of containers of different sizes and materials.

[0034] In one embodiment, see Figure 2 The heating module further includes a thermal resistance plate 2. The thermal resistance plate 2 is disposed on one side of the heating area and is arranged opposite to the heat flow control component 7. The space formed between the two constitutes the heating area for thermally stimulating the filling container.

[0035] The thermal resistance plate 2 is made of polytetrafluoroethylene (PTFE). PTFE has extremely low thermal conductivity (approximately 0.25 W / (m·K)) and high thermal stability, which allows the thermal resistance plate to effectively block heat energy from being conducted to the environment. When the heat flow control component 7 applies thermal excitation to the container, the PTFE thermal resistance plate 2, acting as a low thermal conductivity boundary, reflects or confines most of the heat energy within the heating area, significantly reducing the ineffective dissipation of heat energy to the outside of the device and the supporting structure.

[0036] See Figure 3 and Figure 4 By precisely configuring the thermal resistance plate 2 and the heat flow control component 7, this embodiment physically constructs a constrained heat flow field. This structure guides the energy of thermal excitation more concentratedly to the container under test, rather than allowing it to diffuse into the surrounding space. Its direct effect is to improve the energy utilization efficiency of thermal excitation, enabling a more significant and stable axial temperature gradient to be generated at the liquid level interface of the container under the same input power.

[0037] In summary, by introducing a polytetrafluoroethylene (PTFE) thermal resistance plate 2 and forming a specific heating area configuration, this embodiment achieves active management and optimization of the thermal field. This not only reduces overall energy consumption but also ensures the generation of high-quality, high signal-to-noise ratio temperature comparison signals, laying a reliable thermal foundation for subsequent infrared imaging detection of liquid levels, thereby guaranteeing the accuracy and consistency of the final temperature measurement at the system level.

[0038] In other embodiments, the heating area can be heated from multiple sides.

[0039] In one embodiment, the image acquisition module 6 further includes an infrared detector disposed on one side of the imaging area. The infrared detector is used to acquire a temperature distribution image containing liquid level characteristics of the filling container within the imaging area. The infrared detector can be mounted in the measuring device via a connecting bracket 5.

[0040] Preferably, the infrared detector is an uncooled focal plane array detector with a response band covering the long-wave infrared spectrum range of 8 to 12 micrometers. Its core sensing unit is made of thermosensitive materials such as vanadium oxide or amorphous silicon. Radiation in this band has good penetration through glass and represents the main energy distribution area of ​​thermal radiation from objects at room temperature. The detector has a high resolution, such as 640×512 pixels, which ensures that it can resolve the temperature distribution on the container surface with sufficient spatial detail, providing a hardware foundation for accurately capturing minute temperature gradients. The volume of the uncooled focal plane array detector can be as small as 26×26×41 mm. 3Power consumption ≤ 1W. The infrared detector can also be used with dedicated signal conditioning circuits to obtain thermal images with clearer outlines and richer grayscale levels, thereby achieving high-precision analysis of minute temperature gradients and interface positions.

[0041] Conventional infrared detectors have low infrared radiation penetration through glass containers, making it difficult to effectively acquire liquid level information inside the bottle. Therefore, a narrow-band filter is integrated into the optical imaging path of the infrared detector to enhance the sensitivity of acquiring the weak infrared radiation signal transmitted through the glass container. The infrared detector then uses this narrow-band filter to photograph the filled container entering the imaging area, thereby acquiring a two-dimensional temperature distribution image of the container surface containing liquid level characteristics.

[0042] The narrowband filter is an optical element. Its function is to perform spectral selection, allowing only infrared radiation within a specific narrow wavelength range to pass through while strongly suppressing radiation outside that band. Its transmission band is selected to match the "transmission window" of materials such as ordinary glass in the long-wave infrared region, thereby significantly enhancing the relative intensity of weak thermal radiation signals emitted from the liquid level interface inside the container and penetrating the bottle wall, thus improving the system's detection capability for semi-transparent containers such as glass. By precisely selecting the working wavelength of the narrowband filter, it achieves high transmittance in the target infrared spectrum while maintaining good transmission characteristics of ordinary glass materials in this band. This allows it to filter out ambient stray light and enhance the transmission signal of the glass material in a specific wavelength range, enabling the infrared camera to "penetrate" the bottle wall and directly sense the thermal boundary generated by the internal liquid level, thereby achieving high-precision resolution of temperature gradients and interface pixel positions at the 1℃ / mm level.

[0043] More specifically, the narrowband filter can be an interference filter manufactured using multilayer hard film coating technology. Its substrate material is typically a material with high transmittance to long-wave infrared light, such as germanium, silicon, or zinc selenide. Narrowband filtering is achieved by alternately depositing dozens of layers of specific high- and low-refractive-index dielectric films, each with an optical thickness of one-quarter of the center wavelength, onto the substrate, such as a combination of zinc sulfide and germanium, using the principle of optical interference. Its center wavelength is precisely designed within the range of 9 μm to 11 μm, a band that falls within the peak response range of the detector and corresponds to the relatively high infrared transmittance region of ordinary soda-lime glass. This filter is optically mounted in front of the lens of an infrared detector or integrated within the lens assembly.

[0044] Through the combination of the aforementioned optical and detection components, the image acquisition module of this embodiment can acquire high-contrast, high-signal-to-noise ratio container thermal images in complex industrial environments. This image clearly reflects the temperature distribution characteristics generated by upstream thermal excitation, precisely corresponding to the liquid level height, providing a reliable and high-quality data source for subsequent liquid level information extraction. The entire module achieves high performance while also possessing the advantages of compact structure and low power consumption, making it easy to integrate into modern automated production lines.

[0045] Infrared image acquisition is susceptible to interference from ambient background radiation, leading to poor stability of detection results. Therefore, in one embodiment, the image acquisition module further includes a radiation panel 3. This radiation panel 3 is disposed on one side of the imaging area, opposite to the infrared detector, with the space between them forming the imaging area. The radiation panel 3 serves to provide a controlled and uniform infrared radiation background for actively standardizing the imaging environment and eliminating interference from stray environmental radiation.

[0046] The radiation panel 3 is preferably made of zinc sulfide. Zinc sulfide (ZnS) exhibits significant low infrared absorption and high thermal stability in the long-wave infrared band, enabling the panel itself to function as a highly efficient and temperature-uniform gray-body radiation source when heated. Its low absorption characteristics ensure that the panel primarily reflects or emits radiation within its controlled temperature range, rather than absorbing and re-emitting stray radiation from the environment. This provides a clean and stable background reference for imaging, suppressing environmental thermal disturbances and ensuring that the signal-to-noise ratio of the temperature distribution image is between 30-40 dB. The radiation panel 3 can also be made of other materials with low absorption and high thermal stability.

[0047] To achieve precise background control, the radiating panel 3 is coupled to a precision temperature control system. This system uses a closed-loop feedback mechanism to dynamically maintain the surface temperature of the radiating panel 3 at a constant level that is 8°C to 15°C above the ambient temperature. This preset temperature bias, for example, is an optimized technical parameter. Maintaining a constant background temperature that is moderately higher than the ambient temperature ensures that the background area appears as a known and uniform surface with high radiance in the infrared detector's field of view.

[0048] The core effect of this design lies in active noise suppression. Stray infrared radiation emitted by other random heat sources in the workshop environment, such as equipment, people, and lighting, as well as their complex reflections on object surfaces, are partially masked or normalized by the high and stable background radiation when they reach the infrared detector. From a signal processing perspective, this is equivalent to suppressing low-frequency background fluctuation noise in the image, thus significantly highlighting the thermal radiation profile and characteristics of the tested filling container in the final acquired temperature distribution image. This physically improves the image's signal-to-noise ratio, laying a crucial foundation for the subsequent accurate extraction of weak liquid level interface temperature gradient signals.

[0049] By precisely controlling the temperature, the background temperature is consistently higher than the ambient temperature, reducing interference from environmental thermal disturbances on the infrared thermal signal measured at the liquid surface and ensuring measurement accuracy. Preferably, the temperature of the radiant panel is controlled at a preset temperature, which is 8°C to 15°C higher than the ambient temperature. A closed-loop PID temperature control system maintains the background temperature at a constant 10°C above the ambient temperature. This controlled, uniform, high-radiation background effectively cancels out random reflections from other heat sources within the workshop, thereby reducing background noise in the infrared thermal image and highlighting the thermal profile of the measured bottle. Specifically, the closed-loop PID temperature control system can be a temperature closed-loop servo mechanism consisting of a thin-film heating element integrated on the back of the radiant panel, a temperature sensor in thermal contact with it, and a controller that receives sensor feedback and dynamically adjusts the power of the heating element according to a PID algorithm.

[0050] Information about the type of filling container, such as material and specifications, can be input into the measuring device through a preset method, or it can be actively identified by the measuring device.

[0051] In one embodiment, the infrared imaging non-contact measurement device for the liquid level of multi-material filling containers further includes a visual recognition module 9 located upstream of the heating area. The visual recognition module 9 acquires visible light images of the filling container and obtains at least one type of information about the filling container, including material, specifications, etc. The visual recognition module 9 can be fixed by a connecting bracket 8.

[0052] The visual recognition module 9 is based on a high-resolution visible light imaging unit, typically an industrial-grade color camera. This unit operates in the visible spectrum and can capture images of the container's surface, thereby acquiring rich visual feature information such as its color, shape, outline size, label pattern, and surface texture.

[0053] By processing and analyzing the acquired visible light images, the visual recognition module 9 can extract key features and compare and classify them with a pre-stored container feature database or template. This process enables automatic identification of container materials (e.g., transparent glass, translucent polyethylene, opaque metal) and their specific specifications (e.g., bottle height, bottle diameter, capacity).

[0054] The recognition results output by this module serve as crucial prior information and are transmitted in real time to the device's backend processing system. Its core value lies in providing an adaptive configuration basis for subsequent infrared image processing and analysis. The system can dynamically call upon matching image processing parameters based on different container materials and specifications.

[0055] By integrating this vision recognition module 9, this device achieves a leap from general-purpose detection to optimized detection for specific containers. It enables the entire system to automatically adapt to frequently changing container types on the production line without manual intervention or recalibration, thus significantly improving production line flexibility, detection accuracy, and overall operational efficiency.

[0056] In one embodiment, the infrared imaging non-contact measurement device for liquid level in multi-material filling containers further includes an image processing module. This module establishes a communication connection with the aforementioned vision recognition module 9 and image acquisition module 6. The image processing module can be integrated on the operating console 4. Its core function is to receive the type information of the filling container provided by the vision recognition module 9, and based on this information, to perform targeted processing and analysis on the temperature distribution image acquired by the infrared image acquisition module 6, and finally output the liquid level measurement result of the filling container.

[0057] The image processing module first receives a temperature distribution image containing liquid level features. Then, based on the container material and specifications identified by the visual recognition module 9, it dynamically selects or adjusts the appropriate set of image processing parameters and data analysis model. For example, the system can employ different image enhancement and boundary sharpening strategies for materials with different wall thicknesses or infrared transmission characteristics.

[0058] By analyzing the temperature distribution image, the image processing module can accurately pinpoint the spatial location of the liquid-gas interface within the container, i.e., the liquid level line. Furthermore, by combining the known container geometry model, the system can convert the pixel coordinates of the liquid level line into its absolute physical height from the bottom of the container. In addition, through a built-in volume-height characteristic curve or calculation formula, the module can further map the liquid level height data to the actual volume of the filled liquid, thereby achieving a transformation from non-contact imaging to quantitative volume detection.

[0059] This module can also integrate quality control logic. By comparing the measured liquid level or volume value with the preset qualified range in real time, it can realize the immediate identification and early warning of abnormal filling conditions (such as overfilling or underfilling), and can output relevant signals to the rejection or alarm mechanism of the production line.

[0060] By integrating this image processing module, this device achieves fully automated generation from raw data acquisition to final decision information. It enables the raw signals acquired by the front-end physical sensors to be intelligently transformed into high-precision liquid level and volume data that can be directly used for production control, based on the key prior knowledge of container type, thus forming a complete, closed-loop intelligent measurement system.

[0061] The image processing module described above can analyze temperature distribution images using methods such as edge detection, threshold segmentation, and contour extraction, which are common in digital image processing.

[0062] In one embodiment, the infrared imaging non-contact measurement device for liquid level of multi-material filling containers also includes an incoming material sensing module 10 located upstream of the visual recognition module 9. The hardware core of the incoming material sensing module 10 includes a laser emitter and a laser receiver, which are installed on both sides of the filling container conveying path in a facing manner.

[0063] The incoming material sensing module 10 operates based on photoelectric detection. A laser emitter continuously emits a visible light beam, for example, with a center wavelength of 650 nanometers. This laser beam crosses the transmission path and is stably received by a laser receiver on the opposite side. When the filling container moves with the production line and enters the detection area, the container body intercepts and blocks the laser beam, causing a sudden change in the light signal received by the receiver.

[0064] This change in the optical signal is converted into a clear electrical level transition signal, such as a falling edge from high to low. This signal is transmitted in real time to the central control unit of the device and is defined as a system-level synchronous trigger command. This command serves as the logical starting point for the entire ordered measurement process, precisely activating the subsequent heating module and image acquisition module 6, causing them to start working according to a preset timing sequence.

[0065] By introducing the incoming material sensing module 10 and establishing the aforementioned triggering logic, this embodiment achieves automatic synchronization between the device's operating cycle and the production line's logistics. Its core effect is that it ensures that core energy-consuming units such as heating and imaging are only activated when a measured container arrives. During idle periods without material, the system automatically enters a low-power standby state. This not only significantly reduces the overall energy consumption of the equipment but also avoids unnecessary wear and heat accumulation on critical components such as infrared radiation sources and detectors, thereby effectively extending the equipment's service life and improving the system's reliability and economy.

[0066] In one embodiment, the infrared imaging non-contact measurement device for liquid level in multi-material filling containers further includes a conveying module 1. The conveying module 1 is provided with a bearing surface for carrying the filling containers and drives the containers on the bearing surface to move along a predetermined path in a continuous or stepwise manner. Through the conveying module 1, the filling containers are sequentially conveyed, allowing them to enter and pass through the detection area of ​​the incoming material sensing module 10, the field of view of the visual recognition module 9, the heating area of ​​the heating module, and the imaging area of ​​the image acquisition module 6 in sequence.

[0067] The movement path of the conveying module 1 can be designed in various forms according to the layout of the actual production line, such as a straight line, an arc, or a track with a reversing structure. This module can be an independent conveying mechanism specifically configured for this measuring device, thus forming a fully functional integrated detection unit; alternatively, it can be an existing general-purpose conveyor system on the liquid filling production line, in which case the various functional modules of this measuring device are installed on the side of the corresponding workstation of the conveyor belt in a bypass integrated manner. Specifically, the conveying module 1 can be a straight belt conveyor, a plate chain conveyor, or a synchronous belt conveyor, etc.

[0068] Through the temporal and spatial coordination of the transmission module 1 with each detection and processing module, this embodiment constructs a coherent and automated online measurement process. This ensures that each filling container can sequentially undergo trigger sensing, type identification, thermal excitation, infrared imaging, and data processing according to a preset rhythm and precise spatial sequence. This achieves high-throughput, fully automated, non-contact measurement of liquid level parameters on a continuous production line, significantly improving detection efficiency and the intelligence level of the production line.

[0069] The infrared imaging non-contact measurement device for liquid level in multi-material filling containers of the present invention has the following workflow for multi-material liquid level detection: The system power is turned on, each module is initialized, and the controllable infrared image background noise reduction module begins preheating and raises its radiation panel 3 to a preset temperature; the conveying module 1 carries the filling container to be tested through the container, the incoming material sensing module 10 detects the arrival of the container and outputs a trigger signal, thereby activating the visual recognition module 9 to obtain the container type information; the heat flow control component 7 of the heating module provides non-contact instantaneous thermal excitation to the container passing through the heating area; the container enters the imaging area of ​​the image acquisition module 6, and the infrared detector acquires a temperature distribution image containing liquid level characteristics through a narrow-band filter; the image processing module processes and analyzes the temperature distribution image based on the container type information provided by the visual recognition module 9, obtains the liquid level measurement result, and determines whether the filling is qualified; the system performs corresponding process control on the product according to the determination result, for example, qualified products continue to flow, unqualified products are automatically marked or rejected, and the result of whether the filling is qualified can also be displayed on the screen of the operating console 4.

[0070] After the system power is turned on, the console 4 can also enter a self-test state. Specifically, after the system is powered on, the central control unit integrated in the console 4 automatically executes a series of predefined hardware diagnostic and initialization sequences to ensure that each functional module is in a ready state for normal operation.

[0071] The present invention also discloses a production line, including an infrared imaging non-contact measurement device for the liquid level of multi-material filling containers in the above embodiments.

[0072] In one embodiment, an infrared imaging non-contact measurement method for liquid level in multi-material filling containers, employing the infrared imaging non-contact measurement device for liquid level in multi-material filling containers described in the above embodiment, includes the following steps.

[0073] S100: The arrival of the filling container is detected through non-contact sensing, triggering the measurement process. A laser emitter and receiver monitor the real-time position of containers on the production line. When a container blocks the laser beam, the sensor detects the interruption in the light signal and immediately sends a trigger signal to the control system. This mechanism ensures that the measurement system can accurately start when the container reaches the designated measurement position, achieving automatic synchronization between the measurement sequence and the production cycle.

[0074] S200. Acquire a visible light image of the filling container and identify its material and specifications. A visual recognition module is used to acquire the visible light image. Image processing techniques such as edge detection and feature extraction are employed to obtain key information about the container, including its color, outline, size, and surface texture. The system uses a machine learning classification algorithm to analyze the acquired image features and quickly identify the container's material type (glass, plastic, metal, etc.) and specific specifications. The identification results will serve as the basis for subsequent measurement parameters, ensuring that the needle count setting adopts the optimal measurement strategy for different containers.

[0075] S300. Apply non-contact thermal excitation to the filling container to create a temperature gradient at the liquid level interface. A controllable micro-heat input is applied to the moving container surface through a heat flow control component. Utilizing the difference in specific heat capacity between the liquid and air chambers within the container (the specific heat capacity of the liquid is much greater than that of the gas), a significant temperature gradient is created at the liquid level interface.

[0076] S400. Under controlled thermal background conditions, acquire a temperature distribution image of the filling container after thermal excitation.

[0077] S500. Based on the material and specifications of the filling container, process the temperature distribution image, extract and determine the liquid level information inside the filling container.

[0078] The image acquisition module captures images of the surface temperature distribution of the heated container. Through image noise reduction, contrast enhancement, and threshold segmentation, it clearly identifies the temperature abrupt change boundary at the liquid-air interface, thereby accurately determining the liquid level. Combined with the container type information obtained by the visual recognition module, the system calls a pre-established volume calculation model to convert the liquid level into the actual liquid volume value.

[0079] Preferably, the controlled thermal background condition is a constant state in which the background radiation temperature is 8°C-15°C higher than the ambient temperature, thereby actively suppressing the interference of stray radiation from the environment and significantly improving the signal-to-noise ratio and feature clarity of the acquired image.

[0080] In the description of this specification, the use of terms such as "Embodiment 1," "this embodiment," or "in one embodiment" indicates that the specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example; moreover, the specific features, structures, materials, or characteristics described may be combined in any appropriate manner in one or more embodiments or examples.

[0081] In the description of this specification, the terms "connection," "installation," "fixing," "setting," and "having" are 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 this application according to the specific circumstances.

[0082] In the description of this specification, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0083] The above description of the embodiments is intended to enable those skilled in the art to understand and apply the technology of this invention. Those skilled in the art can easily make various modifications to these examples and apply the general principles described herein to other embodiments without creative effort. Therefore, this invention is not limited to the above embodiments. Modifications in the following situations should be within the scope of protection of this invention: ① New technical solutions implemented based on the technical solution of this invention and combined with existing common knowledge, where the technical effects of the new technical solution do not exceed the technical effects of this invention; ② Equivalent substitutions of some features of the technical solution of this invention using known technology, resulting in the same technical effects as those of this invention; ③ Extendable technical solutions based on the technical solution of this invention, where the substantive content of the extended technical solution does not exceed the technical solution of this invention; ④ Equivalent transformations made using the content of this specification and drawings, directly or indirectly applied to other related technical fields.

Claims

1. An infrared imaging non-contact level measurement device for multi-material filled containers, comprising: a housing; a lens assembly mounted to the housing; a camera assembly mounted to the housing; a light source assembly mounted to the housing; a processor mounted to the housing; and a memory mounted to the housing. include: A heating module includes a heating area, wherein the heating module applies non-contact thermal excitation to the heating area, thereby creating a temperature gradient at the liquid level interface in the filling container located within the heating area. An image acquisition module includes an imaging area, which acquires a temperature distribution image containing liquid level characteristics of a filling container within the imaging area, wherein the imaging area is located downstream of the heating area.

2. The measuring device of claim 1, wherein, The heating module also includes a heat flow control component located on one side of the heating area. The heat flow control component integrates a radiation element and / or a convection duct. The heat flow control component provides non-contact thermal excitation to the heating area through gas convection and / or radiation.

3. The measuring device of claim 2, wherein, The heating module also includes a thermal resistance plate, and the area between the thermal resistance plate and the heat flow control component is the heating area. The thermal resistance plate is made of polytetrafluoroethylene.

4. The measuring device according to any one of claims 1 to 3, characterized in that The image acquisition module also includes an infrared detector located on one side of the imaging area. A narrow band filter is provided on the optical path of the infrared detector. The infrared detector acquires a temperature distribution image containing liquid level characteristics of the filling container in the imaging area through the narrow band filter.

5. The measuring device of claim 4, wherein, The image acquisition module also includes a radiation panel, and the area between the radiation panel and the infrared detector is the imaging area; the radiation panel is made of zinc sulfide, and / or the temperature of the radiation panel is controlled at a preset temperature, which is 8°C to 15°C higher than the ambient temperature.

6. The measuring device according to any one of claims 1 to 3 or 5, characterized in that It also includes a visual recognition module located upstream of the heating area, which acquires visible light images of the filling container and obtains at least one type information of the filling container, including material and specifications.

7. The measuring device of claim 6, wherein, It also includes an image processing module, which processes and / or analyzes the temperature distribution image based on the type information of the filling container, and obtains the liquid level measurement result of the filling container.

8. The measuring device of claim 7, wherein, It also includes an incoming material sensing module located upstream of the visual recognition module. The incoming material sensing module includes a laser emitter and a laser receiver arranged opposite each other. The output signal of the incoming material sensing module is used to trigger the start-up of the heating module and the image acquisition module.

9. A method of non-contact measurement of the liquid level in a multi-material filled container by infrared imaging, using a device for non-contact measurement of the liquid level in a multi-material filled container by infrared imaging according to any one of claims 1 to 8, characterized in that Includes the following steps: S100: The arrival of the filling container is detected through non-contact sensing, triggering the measurement process; S200: Acquire a visible light image of the filling container and identify the material and specifications of the filling container; S300. Apply non-contact thermal excitation to the filling container to form a temperature gradient at the liquid level interface of the filling container. S400. Under controlled thermal background conditions, acquire a temperature distribution image of the filling container after thermal excitation; S500. Based on the material and specifications of the filling container, process the temperature distribution image, extract and determine the liquid level information inside the filling container.

10. The measurement method of claim 9, wherein, The controlled thermal background conditions are a constant state in which the background radiation temperature is 8°C-15°C higher than the ambient temperature.

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