An on-line multi-angle color difference meter

Abstract

This invention discloses an online multi-angle colorimeter, belonging to the field of colorimeter technology. Its key technical features include: a light source module containing multiple LED light sources arranged at preset angles towards the measurement area; a receiver module positioned at a fixed angle to receive reflected light signals; an optical system connecting the light sources and the receiver module, guiding the light path and filtering out non-measured light; a data processing unit electrically connected to the receiver module, used to convert light signals and calculate color difference values; a housing for fixing the modules and providing a non-contact measurement gap; preferably, the illumination angle includes multiple specific angles, and the receiver module is configured to receive light at a single angle; a height compensation device is provided inside the housing; the optical system includes a beam splitter prism and a filter group; a communication module is included; the LED light sources employ a uniformly distributed LED array; an automatic calibration module is included; and the housing uses a NEMA 4 protection rating enclosure. This invention enables non-contact online measurement, improving measurement efficiency and automation.

Description

Technical Field

[0001] This invention relates to the field of colorimeter technology, and in particular to an online multi-angle colorimeter. Background Technology

[0002] In the field of color measurement, accurately acquiring color information of objects is crucial for many industries, such as automobile manufacturing, paint production, and electronic product appearance inspection. With the continuous improvement of industrial automation, the requirements for color measurement equipment are becoming increasingly stringent. Not only are high-precision measurement results needed, but they also need to adapt to the high-speed, continuous measurement demands of automated production lines. Currently, some color measurement equipment exists on the market, but they have significant shortcomings in meeting the requirements for online, multi-angle, and non-contact measurement.

[0003] Among existing color measurement technologies, handheld multi-angle color difference detectors are quite common. These detectors typically employ a single-light source, multi-detector optical path design. During measurement, the device needs to be held manually and placed close to the product's surface. While this method can obtain color information to some extent, it has several limitations. For example, during measurement, manual operation makes it difficult to ensure that the pressure and angle are completely consistent for each measurement. This affects the accuracy and repeatability of the measurement results, making it impossible to provide stable and reliable color data support for production.

[0004] More importantly, handheld measurement methods have many shortcomings when facing modern automated production lines. For example, automated production lines require measuring equipment to seamlessly integrate with the production process, enabling real-time, online 100% inspection. Handheld devices, however, rely on periodic manual sampling, which is not only lagging and prone to missed inspections, but also cannot meet the demand for 100% inspection of all products in large-scale production. Furthermore, for some special products, such as high-temperature, easily contaminated, or soft workpieces, handheld measurement can pose a danger to operators and easily damage the sample surface, affecting product quality. Therefore, existing color measurement technologies urgently need improvement and innovation to adapt to the new demands of industrial development. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide an online multi-angle colorimeter that enables non-contact online measurement, thereby improving measurement efficiency and automation.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] An online multi-angle colorimeter includes:

[0008] The light source module includes multiple LED light sources, which are arranged at preset angles toward the area to be measured.

[0009] A receiver module is positioned at a fixed angle to receive reflected light signals from the area under test under different illumination angles.

[0010] An optical system, connecting the light source module and the receiver module, is used to guide the light path and filter out non-measured light;

[0011] The data processing unit, electrically connected to the receiver module, is used to convert the light signal into color parameters and calculate the color difference value;

[0012] The housing is used to fix the light source module, receiver module and optical system, and to provide a non-contact measurement gap.

[0013] Preferably, the illumination angle of the light source module includes at least one of 5°, 25°, 45°, 75°, and 110°, and the receiver module is equipped with a sensing chip.

[0014] Preferably, the housing is provided with a height compensation device for adjusting the measurement gap to accommodate samples of different heights. The adjustment range of the height compensation device is 0-5mm. The height compensation device includes a lifting cylinder, and a placement platform for placing the sample is fixedly provided on the top of the lifting cylinder.

[0015] Preferably, the optical system includes a beam splitter prism and a filter group, wherein the beam splitter prism is used to separate reflected light at different angles to the receiver module, and the filter group is used to eliminate ambient light interference.

[0016] Preferably, it also includes a communication module, which is connected to the industrial control system via an Ethernet interface for real-time transmission of measurement data and reception of control commands. The communication module supports I / O protocols.

[0017] Preferably, the LED light source is a uniformly distributed LED array.

[0018] Preferably, it also includes an automatic calibration module, which includes a standard whiteboard and a calibration program for periodically calibrating the instrument's measurement reference.

[0019] Preferably, the housing is a NEMA 4 protection rating enclosure.

[0020] The present invention has the following beneficial effects:

[0021] I. Achieving Non-Contact Online Measurement to Meet the Needs of Automated Production Lines: Traditional handheld multi-angle color difference detectors rely on manual operation, making seamless integration with automated production lines difficult. They cannot achieve real-time, online full inspection, exhibiting lag and a tendency to miss detections, failing to meet the 100% inspection requirements of large-scale production. The online multi-angle color difference meter of this invention, through a specific structure including a light source module, receiver module, optical system, data processing unit, and a housing with a non-contact measurement gap, achieves non-contact online measurement. This measurement method can closely integrate with automated production lines, meeting their requirements for high-speed, continuous measurement, providing timely and accurate color data support for production, and significantly improving production efficiency and product quality stability.

[0022] II. Improved Measurement Accuracy and Repeatability: Traditional handheld devices, when operated manually, struggle to ensure consistent pressure and angle for each measurement, impacting accuracy and repeatability. This invention's online multi-angle colorimeter features multiple LEDs in its light source module positioned at preset angles towards the measurement area. A receiver module at a fixed angle receives reflected light signals. An optical system guides the light path and filters out non-measuring light. A data processing unit converts the light signals into color parameters and calculates the color difference value. This standardized measurement structure and process avoids errors caused by manual operation, ensuring consistent angle and pressure for each measurement, thereby improving the accuracy and repeatability of the measurement results.

[0023] Third, adaptability to samples of different heights: This invention incorporates a height compensation device within the housing, with an adjustment range of 0-5mm. The height compensation device includes a lifting cylinder, with a platform for placing the sample fixedly mounted on the top movable part of the cylinder. This design allows the colorimeter to adjust the measurement gap according to samples of different heights, expanding the instrument's applicability. Accurate color measurement can be performed on samples of varying heights, improving the instrument's versatility and practicality.

[0024] IV. Eliminating Ambient Light Interference and Ensuring Measurement Accuracy: The filter array in the optical system effectively eliminates ambient light interference. During color measurement, ambient light may adversely affect the measurement results, leading to inaccurate data. The filter array filters out light rays not required for measurement, allowing only reflected light of specific wavelengths and angles to enter the receiver module, thereby ensuring the accuracy and reliability of the measurement results and improving the instrument's measurement performance in complex environments.

[0025] V. Real-time data transmission and control facilitate production management; the instrument is equipped with a communication module that connects to the industrial control system via an Ethernet interface, enabling real-time transmission of measurement data and reception of control commands, and supporting I / O protocols. This allows production managers to obtain product color measurement information promptly and adjust and control the production process in real time based on the measurement results. Simultaneously, real-time data transmission also facilitates the recording and analysis of production data, providing strong support for production optimization and quality control, further improving the efficiency and level of production management.

[0026] VI. Regular automatic calibration to maintain stable measurement standards: The automatic calibration module includes a standard white board and calibration program, enabling regular correction of the instrument's measurement standards. During prolonged use, the colorimeter's measurement performance may change due to various factors, leading to deviations in measurement results. The automatic calibration module can periodically calibrate the instrument, ensuring it remains in good working order, maintaining stable measurement standards, and thus guaranteeing the accuracy and consistency of measurement results, reducing measurement errors caused by changes in instrument performance.

[0027] VII. Excellent protective performance, adaptable to various working environments; the housing adopts a NEMA 4 protection rating, which has a high level of protection and can effectively prevent dust, water, etc. from entering the instrument, protecting the delicate internal components from damage. This allows the online multi-angle colorimeter to operate normally in a variety of harsh working environments, such as humid and dusty environments, improving the instrument's reliability and durability, and reducing maintenance costs and usage risks.

[0028] 8. Uniform light source distribution ensures measurement consistency; the LED light source uses a uniformly distributed LED array. This design allows the light emitted by the light source to illuminate the test area more evenly, avoiding measurement errors caused by uneven light source distribution. Uniform light distribution ensures that the test area receives consistent lighting conditions at different positions and angles, thereby improving the accuracy and consistency of color measurement and making the measurement results more accurately reflect the color information of the object. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a cross-sectional schematic diagram of the present invention;

[0031] Figure 2This is a schematic diagram of the overall structure of the present invention;

[0032] Figure 3 This is a schematic diagram of the optical path principle of the present invention.

[0033] In the diagram: 1. Light source module; 2. Receiver module; 3. Optical system; 4. Data processing unit; 5. Housing; 501. Lifting cylinder; 502. Placement platform. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 are within the scope of protection of the present invention.

[0035] like Figure 1-3 As shown, the present invention provides an online multi-angle colorimeter, comprising: a light source module 1, which includes multiple LED light sources arranged at preset angles toward the area to be measured; a receiver module 2, which is positioned at a fixed angle and is used to receive reflected light signals from the area to be measured under different illumination angles; an optical system 3, which connects the light source module 1 and the receiver module 2 and is used to guide the light path and filter out non-measured light; a data processing unit 4, which is electrically connected to the receiver module 2 and is used to convert the light signals into color parameters and calculate the color difference value; and a housing 5, which is used to fix the light source module 1, the receiver module 2, and the optical system 3, and to provide a non-contact measurement gap.

[0036] like Figure 1 As shown, the online multi-angle colorimeter of this embodiment detects the color of an object based on the principle of optical measurement. Multiple LED light sources in the light source module 1 are arranged at preset angles of 5°, 25°, 45°, 75°, and 110° towards the area to be measured. When the instrument is turned on, these LED light sources emit light simultaneously, illuminating the surface of the object at different angles. Because the absorption and reflection characteristics of the object surface differ at different angles of incident light, the area to be measured will reflect light signals with different characteristics under different illumination angles.

[0037] Receiver module 2 is positioned at a fixed angle and contains a sensing chip. Its function is to receive light signals reflected from the area under test at different illumination angles. Optical system 3 connects light source module 1 and receiver module 2. The beam splitter inside optical system 3 separates reflected light at different angles, ensuring that reflected light at different angles accurately reaches receiver module 2 along its corresponding path. Simultaneously, the filter group in optical system 3 filters out non-measurement light, such as ambient light and other interfering light, allowing only reflected light of specific wavelengths and angles relevant to the measurement to enter receiver module 2, thereby improving measurement accuracy and anti-interference capability. After receiving the reflected light signal, receiver module 2 converts it into an electrical signal and transmits it to the electrically connected data processing unit 4. Data processing unit 4, based on a preset algorithm and program, first converts the received light signal into color parameters, such as chromaticity coordinates and luminance, and then calculates the color difference value based on these color parameters to determine the difference between the color of the object under test and the standard color.

[0038] The housing 5 serves to fix and protect the internal components, securing the light source module 1, receiver module 2, and optical system 3 in appropriate positions to ensure the relative positional accuracy between the components, thereby ensuring measurement stability. Simultaneously, the non-contact measurement gap on the housing 5 allows the colorimeter to operate without contact with the surface of the object being measured, avoiding damage to the surface caused by contact, reducing measurement errors due to contact, and adapting to the online measurement needs of automated production lines, enabling high-speed, continuous color detection.

[0039] The online multi-angle colorimeter of this embodiment enables high-precision, multi-angle measurement of object color. Multiple preset-angle LED light sources illuminate the object from different directions, allowing for the acquisition of the object's surface reflection characteristics under varying lighting conditions. This provides a more comprehensive reflection of the object's color information, improving accuracy and reliability compared to single-angle measurements. The fixed-angle receiver module 2, combined with the beam splitting and filtering functions of the optical system 3, accurately receives and processes reflected light signals, effectively eliminating interference from ambient light and further enhancing measurement accuracy. The data processing unit 4 quickly converts the light signal into color parameters and calculates the color difference value, providing timely and accurate data support for color quality control during production. The non-contact measurement method not only protects the surface of the object being measured but also meets the high-speed, continuous measurement requirements of automated production lines, significantly improving production efficiency and product quality stability.

[0040] When the colorimeter is activated for measurement, LED light sources at different angles emit light simultaneously, illuminating the surface of the sample at their respective specific angles. Due to the complex microstructure and optical properties of the object's surface, the absorption, reflection, and scattering of incident light vary depending on the angle. For example, a smooth surface may exhibit specular reflection under different angles of incident light, while a rough surface tends to have diffuse reflection, and the intensity and color distribution of reflected light also differ at different angles. Receiver module 2 is configured to receive light signals at a single fixed angle. It can capture the light reflected from the sample at that specific receiving angle under illumination from different angles of light sources. In this way, information on the reflected light characteristics of the sample under different lighting conditions can be obtained, and this information, when combined, can more comprehensively and accurately reflect the color characteristics of the sample. Compared to single-angle illumination and reception, the combination of multi-angle illumination and single-angle reception avoids the limitations of single-angle measurement and reduces the influence of factors such as sample surface texture and gloss on the color measurement results, thereby improving the accuracy and reliability of the measurement.

[0041] The height compensation device installed inside the housing 5 of this invention is mainly used to adjust the measurement gap to accommodate samples of different heights. The device uses a lifting cylinder 501 as its core component, with a placement platform 502 fixedly mounted on its top for placing the sample. When measuring samples of different heights, the movement of the lifting cylinder 501 is controlled, causing its top movable part to rise or fall, thereby moving the placement platform 502 vertically. This allows for precise adjustment of the distance between the sample and the light source module 1 and receiver module 2 according to the sample's height, ensuring the measurement gap remains within a suitable range and guaranteeing measurement accuracy and stability. For example, for shorter samples, the placement platform 502 is lowered to bring it closer to the measuring components; for taller samples, the placement platform 502 is raised to avoid measurement errors caused by improper distance.

[0042] The beam splitter in the optical system 3 of this invention operates based on the principles of light refraction and reflection. When reflected light from different angles enters the optical system 3, it illuminates the beam splitter. Since the incident angles of light rays at different angles are different when they strike the interface of the beam splitter, according to the laws of refraction and reflection, the light rays undergo varying degrees of refraction and reflection within the beam splitter. By precisely designing its optical structure and angles, the beam splitter can separate reflected light from different angles along specific paths, directing them to different parts or channels of the receiver module 2. This allows the receiver module 2 to receive reflected light signals from different angles, providing a basis for accurate analysis of the color characteristics of an object under different lighting angles. The filter group is mainly used to eliminate ambient light interference. Ambient light contains light of various wavelengths and intensities. If this light enters the receiver module 2, it will mix with the useful light signal reflected by the object under test, interfering with the measurement results. The filter group consists of multiple filters with specific spectral characteristics. Each filter only allows light within a specific wavelength range to pass through, while blocking other wavelengths. By properly selecting and combining these filters, most of the wavelength components in the ambient light that are irrelevant to the measurement can be filtered out, allowing only specific wavelengths of light related to the light reflected from the object under test to pass through. This effectively improves the signal-to-noise ratio of the measurement and ensures the accuracy and reliability of the measurement data.

[0043] This invention's communication module establishes a connection with the industrial control system via an Ethernet interface. Ethernet is a widely used local area network (LAN) communication technology with advantages such as high speed, stability, and reliability. The communication module integrates a network communication chip and related circuitry, enabling it to encode and encapsulate measurement data according to a specific data format, and then transmit the data to the industrial control system in real time via the Ethernet interface. Simultaneously, it can also receive control commands from the industrial control system. These commands are also transmitted to the communication module via the network, where they are decoded and processed before being relayed to other modules of the colorimeter. This enables remote control and operation of the colorimeter, such as starting or stopping measurements and adjusting measurement parameters. The communication module supports I / O protocols, allowing for seamless interface and communication with various I / O devices widely used in industrial control systems. This facilitates data interaction and sharing, further improving the integration and compatibility of the colorimeter in industrial automated production environments.

[0044] The LED array of this invention consists of multiple LED beads arranged uniformly according to a certain geometric shape and spacing. This uniform distribution design is based on the principle of light superposition in optics, where the light emitted by each LED bead propagates in space and superimposes with each other. When the light shines on the surface of the object under test, the uniform distribution of the LED beads creates a relatively uniform illumination area on the surface. Light emitted from LED beads at different positions strikes the object surface from different angles, and after reflection and scattering by the object surface, the reflected light also exhibits a relatively uniform distribution. This uniform illumination condition avoids measurement errors caused by excessively strong or weak local illumination, allowing the reflected light signal received by the receiver module 2 to more accurately reflect the true color and optical characteristics of the object under test, thereby improving the accuracy and stability of the measurement.

[0045] This invention also includes an automatic calibration module, which comprises a standard white plate and a calibration program for periodically calibrating the instrument's measurement reference. The automatic calibration module includes a standard white plate and a calibration program. The standard white plate is a reference object with known and stable optical properties; its surface has high reflectivity and a uniform reflection spectrum, capable of reflecting light within a specific wavelength range, and its reflectivity remains relatively stable under different times and environments. The calibration program is a pre-written algorithm and operating procedure stored in the colorimeter's control system or memory. When calibration is required, the calibration program controls the colorimeter's LED light source to emit light of a specific intensity and wavelength, illuminating the standard white plate. Receiver module 2 receives the light reflected back from the standard white plate and converts it into an electrical signal. The calibration program compares and analyzes the received electrical signal with the known optical parameters of the standard white plate, calculating the deviation between the current measurement system and the standard state. Then, based on the calculated deviation value, the calibration program adjusts and corrects the parameters of the measurement system, such as adjusting the luminous intensity of the light source and the gain of receiver module 2, so that the measurement reference of the measurement system returns to the standard state, thereby ensuring the accuracy of subsequent measurements.

[0046] like Figure 1As shown, housing 5 adopts a NEMA 4 protection rating. NEMA 4 is a protection standard for electrical equipment enclosures, primarily addressing protection against dust, water splashes, and other hazards encountered in indoor and outdoor environments. NEMA 4 enclosures achieve their protective function through special design and material selection. For dust protection, the enclosure employs a sealed structure design, with sealing strips and gaskets used at the connections between components to effectively prevent dust from entering the interior of housing 5, protecting internal electronic and optical components from dust contamination and impact, ensuring normal instrument operation and measurement accuracy. For waterproofing, the enclosure can withstand low-pressure water splashes from all directions, and its structural design prevents water from seeping in through gaps and interfaces. For example, waterproof connectors are used at the enclosure's interfaces to prevent water from entering the interior of housing 5 along the cables; the surface of the enclosure undergoes special treatment, providing a certain degree of waterproofing and withstanding a certain level of rain and water splashes.

[0047] The above are merely specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions, or modifications made based on the present invention to solve essentially the same technical problems and achieve essentially the same technical effects are all covered within the protection scope of the present invention.

Claims

1. An online multi-angle colorimeter, characterized in that, include: The light source module (1) includes multiple LED light sources, which are arranged at preset angles toward the area to be measured. Receiver module (2), which is set at a fixed angle position and is used to receive the reflected light signal of the area to be tested under different illumination angles; An optical system (3) is connected to the light source module (1) and the receiver module (2) for guiding the light path and filtering out non-measured light; Data processing unit (4), which is electrically connected to receiver module (2), is used to convert light signals into color parameters and calculate color difference values; Housing (5), which is used to fix the light source module (1), receiver module (2) and optical system (3) and to set a non-contact measurement gap.

2. The online multi-angle colorimeter according to claim 1, characterized in that: The illumination angle of the light source module (1) includes at least one of 5°, 25°, 45°, 75°, and 110°, and the receiver module (2) is equipped with a sensing chip.

3. The online multi-angle colorimeter according to claim 2, characterized in that: The housing (5) is provided with a height compensation device for adjusting the measurement gap to accommodate samples of different heights. The adjustment range of the height compensation device is 0-5mm. The height compensation device includes a lifting cylinder (501). The top of the lifting cylinder (501) is fixedly provided with a placement platform (502) for placing the sample.

4. The online multi-angle colorimeter according to claim 3, characterized in that: The optical system (3) includes a beam splitter and a filter group. The beam splitter is used to separate reflected light at different angles to the receiver module (2), and the filter group is used to eliminate ambient light interference.

5. An online multi-angle colorimeter according to claim 4, characterized in that: It also includes a communication module, which is connected to the industrial control system via an Ethernet interface for real-time transmission of measurement data and reception of control commands. The communication module supports I / O protocols.

6. An online multi-angle colorimeter according to claim 5, characterized in that: The LED light source uses a uniformly distributed LED array.

7. An online multi-angle colorimeter according to claim 6, characterized in that: It also includes an automatic calibration module, which includes a standard whiteboard and calibration program for periodically calibrating the instrument's measurement reference.

8. An online multi-angle colorimeter according to claim 7, characterized in that: The housing (5) is a NEMA 4 protection level enclosure.

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