A color temperature calibration method and system

Abstract

This disclosure provides a color temperature calibration method and system. By determining a reference color temperature parameter, and for each unit to be calibrated, determining the color temperature deviation based on the difference between the actual chromaticity parameter and the reference color temperature parameter, determining a compensation coefficient for each unit to be calibrated based on the color temperature deviation, and writing the compensation coefficient into the control unit corresponding to the unit to be calibrated, color temperature deviation calibration can be completed for each unit to be calibrated, effectively solving the problem of inconsistent color temperature in different areas, improving the overall color temperature consistency of lighting, and enhancing the visual experience. Furthermore, by re-collecting the actual chromaticity parameters of each unit to be calibrated, and re-determining the color temperature deviation of each unit based on the actual chromaticity parameters, the color temperature deviation can be gradually reduced to the required range through iterative calibration, ensuring calibration accuracy.

Description

Technical Field

[0001] This disclosure relates to the field of lighting technology, and in particular to a color temperature calibration method and system. Background Technology

[0002] LED lighting technology, with its advantages of high efficiency, energy saving, long lifespan, and environmental friendliness, has been widely used in various fields such as commercial lighting, home lighting, and industrial lighting. However, as people's demands for lighting quality continue to increase, the issue of color temperature consistency in LED luminaires is becoming increasingly prominent.

[0003] Currently, in the production and practical application of LED lighting fixtures, there is a common problem of significant differences in the color temperature of different areas within the same space, which affects visual comfort and spatial aesthetics. Summary of the Invention

[0004] The main objective of this disclosure is to provide a color temperature calibration method and system to solve the above-mentioned problems.

[0005] To achieve the above objectives, a first aspect of this disclosure provides a color temperature calibration method, comprising: Collect the actual chromaticity parameters of each unit to be calibrated and determine the reference color temperature parameters; For each of the units to be calibrated, the color temperature deviation is determined based on the difference between the actual colorimetric parameters and the reference color temperature parameters; The compensation coefficient for each of the units to be calibrated is determined based on the color temperature deviation. Write the compensation coefficient into the control unit corresponding to the unit to be calibrated; The actual chromaticity parameters of each of the units to be calibrated are re-acquired, and the color temperature deviation of each of the units to be calibrated is determined again based on the actual chromaticity parameters. When the color temperature deviation does not reach the threshold requirement, the compensation coefficient of each of the units to be calibrated is determined again based on the color temperature deviation and written to the control unit until the color temperature deviation reaches the threshold requirement or the maximum number of iterations is reached.

[0006] In some embodiments, determining the compensation coefficient for each of the units to be calibrated based on the color temperature deviation includes: The color temperature type of the unit to be calibrated is determined, and the color temperature type is used to indicate whether the unit to be calibrated uses a single-color temperature LED or a dual-color temperature LED. The compensation coefficient for each of the units to be calibrated is determined based on the color temperature type and the color temperature deviation.

[0007] In some embodiments, determining the compensation coefficient for each of the units to be calibrated based on the color temperature type and the color temperature deviation includes: When the color temperature type indicates that the unit to be calibrated uses dual-color temperature LEDs, the first duty cycle adjustment amount and the second duty cycle adjustment amount corresponding to each unit to be calibrated are determined as compensation coefficients. If the color temperature deviation indicates that the unit to be calibrated is displaying a warmer color temperature, the first duty cycle adjustment amount is used to increase the PWM duty cycle of the cool color temperature LEDs, and the second duty cycle adjustment amount is used to decrease the PWM duty cycle of the warm color temperature LEDs. If the color temperature deviation indicates that the unit to be calibrated is displaying a cooler color temperature, the first duty cycle adjustment amount is used to increase the PWM duty cycle of the warm color temperature LEDs, and the second duty cycle adjustment amount is used to decrease the PWM duty cycle of the cool color temperature LEDs. When the color temperature type indicates that the unit to be calibrated uses a single-color temperature LED, the third duty cycle adjustment amount corresponding to each unit to be calibrated is determined from the preset duty cycle color temperature mapping table according to the color temperature deviation amount as a compensation coefficient, or the color temperature deviation amount is input into the fitting model to determine the third duty cycle adjustment amount corresponding to each unit to be calibrated as a compensation coefficient.

[0008] In some embodiments, determining the compensation coefficient for each of the units to be calibrated based on the color temperature type and the color temperature deviation includes: The driving current compensation amount corresponding to each of the units to be calibrated is determined from the preset current color temperature curve based on the color temperature deviation amount, and used as the compensation coefficient.

[0009] In some embodiments, determining the compensation coefficient for each of the units to be calibrated based on the color temperature type and the color temperature deviation includes: Based on the color temperature deviation, the fourth duty cycle adjustment amount corresponding to each of the units to be calibrated is determined from the preset duty cycle color temperature mapping table as the first compensation coefficient. The driving current compensation amount corresponding to each of the units to be calibrated is determined from the preset current color temperature curve based on the color temperature deviation amount as the second compensation coefficient. The first compensation coefficient is used for coarse adjustment, and the second compensation coefficient is used for fine adjustment after coarse adjustment based on the first compensation coefficient.

[0010] In some embodiments, each of the units to be calibrated is a lamp bead with an independent driving channel, and determining the compensation coefficient of each unit to be calibrated based on the color temperature type and the color temperature deviation includes: The fourth duty cycle adjustment amount corresponding to each of the units to be calibrated is determined as a compensation coefficient based on the color temperature type and the color temperature deviation.

[0011] In some embodiments, the actual chromaticity parameters include original chromaticity coordinates, correlated color temperature, and DUV values, and the determination of the reference color temperature parameters includes at least one of the following: The target correlated color temperature is obtained by calculating the mean value of the correlated color temperature of all units to be calibrated in the same or different levels, and the target color coordinates are obtained by calculating the mean value of the original color coordinates of all units to be calibrated in the same or different levels. The target correlated color temperature and the target color coordinates are determined as reference color temperature parameters. The target correlated color temperature is obtained by calculating the median of the correlated color temperatures of all the units to be calibrated, and the target color coordinates are obtained by calculating the median of the original color coordinates of all the units to be calibrated. The target correlated color temperature and the target color coordinates are determined as reference color temperature parameters. The nominal color temperature of the unit to be calibrated in the same or different levels is used as the target correlated color temperature, and the nominal original color coordinates of the unit to be calibrated in the same or different levels are used as the target color coordinates. The target correlated color temperature and the target color coordinates are determined as the reference color temperature parameters. The correlated color temperature with the smallest difference from the nominal color temperature of the luminaire design is taken as the target correlated color temperature, and the original color coordinate with the smallest difference from the nominal original color coordinate of the luminaire design is taken as the target color coordinate. The target correlated color temperature and the target color coordinate are determined as the reference color temperature parameters. The unit to be calibrated with the smallest DUV value is taken as the target calibration unit, the correlated color temperature corresponding to the target calibration unit is taken as the target correlated color temperature, the original color coordinates corresponding to the target calibration unit are taken as the target color coordinates, and the target correlated color temperature and the target color coordinates are determined as the reference color temperature parameters.

[0012] In some embodiments, the actual chromaticity parameter includes original chromaticity coordinates, the reference chromaticity parameter includes target chromaticity coordinates, and determining the color temperature deviation based on the difference between the actual chromaticity parameter and the reference color temperature parameter includes: The original color coordinates and the target color coordinates are transformed to obtain the original uniform color coordinates and the target uniform color coordinates respectively; The color temperature deviation is determined based on the difference between the original uniform color coordinates and the target uniform color coordinates.

[0013] To achieve the above objectives, a second aspect of this disclosure provides a color temperature calibration system, comprising: The parameter acquisition module is used to acquire the actual colorimetric parameters of each unit to be calibrated and determine the reference color temperature parameters. The deviation determination module is used to determine the color temperature deviation for each of the units to be calibrated based on the difference between the actual colorimetric parameters and the reference color temperature parameters. The compensation coefficient determination module is used to determine the compensation coefficient of each of the units to be calibrated based on the color temperature deviation. A writing module is used to write the compensation coefficient into the control unit corresponding to the unit to be calibrated; The iteration module is used to re-acquire the actual chromaticity parameters of each of the units to be calibrated, and determine the color temperature deviation of each of the units to be calibrated again based on the actual chromaticity parameters. When the color temperature deviation does not reach the threshold requirement, the compensation coefficient of each of the units to be calibrated is determined again based on the color temperature deviation and written to the control unit until the color temperature deviation reaches the threshold requirement or the maximum number of iterations is reached.

[0014] To achieve the above objectives, a third aspect of this disclosure provides a storage medium, which is a computer-readable storage medium storing a computer program that, when executed by a processor, implements the smart lock user behavior model update method described in the first or second aspect embodiments.

[0015] The beneficial effects of the embodiments disclosed herein include: By collecting the actual chromaticity parameters of each unit to be calibrated, a reference color temperature parameter is determined. For each unit to be calibrated, the color temperature deviation is determined based on the difference between the actual chromaticity parameters and the reference color temperature parameter. The compensation coefficient for each unit to be calibrated is determined based on the color temperature deviation. The compensation coefficient is written into the control unit corresponding to the unit to be calibrated. This allows for color temperature deviation calibration for each unit to be calibrated, effectively solving the problem of inconsistent color temperature in different areas, improving the color temperature consistency of overall lighting, and enhancing the visual experience. Furthermore, by re-collecting the actual chromaticity parameters of each unit to be calibrated, the color temperature deviation of each unit to be calibrated is determined again based on the actual chromaticity parameters. When the color temperature deviation does not reach the threshold requirement, the compensation coefficient for each unit to be calibrated is determined again based on the color temperature deviation and written into the control unit. This process continues until the color temperature deviation reaches the threshold requirement or the maximum number of iterations is reached. Through iterative calibration, the color temperature deviation can be gradually reduced to the required range, ensuring calibration accuracy. Attached Figure Description

[0016] Figure 1 This is a schematic flowchart of the color temperature calibration method provided in the embodiments of this disclosure; Figure 2 yes Figure 1 A flowchart further includes step S102; Figure 3 yes Figure 1 A flowchart further includes step S103; Figure 4 This is a schematic diagram of the structure of the color temperature calibration system provided in an embodiment of this disclosure. Detailed Implementation

[0017] The accompanying drawings in the embodiments clearly and completely describe the technical solutions in the embodiments of this disclosure. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0018] It is understood that in the specific embodiments of this disclosure, which involve the retrieval of relevant data, when the above embodiments of this disclosure are applied to specific products or technologies, permission or consent from the subject is required, and the collection, use and processing of relevant data must comply with relevant laws, regulations and standards.

[0019] In this disclosure, the terms "module" or "unit" refer to a computer program or part of a computer program that has a predetermined function and works with other related parts to achieve a predetermined goal, and can be implemented wholly or partially using software, hardware (such as processing circuitry or memory), or a combination thereof. Similarly, a processor (or multiple processors or memory) can be used to implement one or more modules or units. Furthermore, each module or unit can be part of an overall module or unit that includes the functionality of that module or unit.

[0020] Reference Figure 1 , Figure 1 This is a flowchart illustrating the color temperature calibration method provided in this embodiment. This color temperature calibration method can be applied to the quality inspection stage of a production line, or it can be used as a maintenance tool for lamps after they leave the factory, integrated into the lamp's control system or external calibration equipment. The method includes steps S101 to S105: Step S101: Collect the actual colorimetric parameters of each unit to be calibrated and determine the reference color temperature parameters.

[0021] Step S102: For each unit to be calibrated, determine the color temperature deviation based on the difference between the actual colorimetric parameters and the reference color temperature parameters.

[0022] Step S103: Determine the compensation coefficient for each unit to be calibrated based on the color temperature deviation.

[0023] Step S104: Write the compensation coefficient into the control unit corresponding to the unit to be calibrated.

[0024] Step S105: Reacquire the actual chromaticity parameters of each unit to be calibrated, and determine the color temperature deviation of each unit to be calibrated again based on the actual chromaticity parameters. When the color temperature deviation does not reach the threshold requirement, determine the compensation coefficient of each unit to be calibrated again based on the color temperature deviation and write it to the control unit until the color temperature deviation reaches the threshold requirement or the maximum number of iterations is reached.

[0025] Regarding step S101 above, the unit to be calibrated can be one or more of two levels. The first level is the LED bead level, that is, each LED bead within the same lamp fixture. The second level is the lamp fixture level, that is, each LED lamp fixture within the same space, such as an exhibition hall, an office, or a production line. Embodiments of this disclosure can perform calibration at a single level or in combination. For example, to simultaneously achieve consistency within and between lamps, LED bead-level calibration can be performed first on the LED beads within each lamp fixture, and then each calibrated lamp fixture can be used as a new unit to be calibrated for lamp fixture-level calibration.

[0026] Actual chromaticity parameters are physical quantities characterizing the color properties of a light source. Their acquisition methods can include, but are not limited to, using specialized equipment such as integrating spheres, spectrometers, and color temperature probes, or image-based chromaticity extraction algorithms. In one embodiment, the acquired actual chromaticity parameters may include original chromatic coordinates, correlated color temperature (CCT), and DUV values. The original chromatic coordinates can be CIE 1931 chromatic coordinates (x, y). The DUV values ​​quantify the deviation between the chromatic coordinates and the blackbody locus; the smaller the absolute value, the whiter the light source and the purer the visual perception. Optionally, luminous flux Φ can also be acquired to simultaneously calibrate the brightness consistency of the luminaire while calibrating the color temperature.

[0027] A reference color temperature parameter is used to define a common color temperature level that all units to be calibrated should achieve. In some embodiments, the process of determining the reference color temperature parameter described above may include at least one of the following: The target correlated color temperature is obtained by calculating the mean of the correlated color temperatures of all units to be calibrated within the same or different levels. The target color coordinates are obtained by calculating the mean of the original color coordinates of all units to be calibrated within the same or different levels. The target correlated color temperature and target color coordinates are then defined as the reference color temperature parameters. Here, "same level" can refer to all LEDs within the same lamp or all lamps in the same space. This approach is suitable for general scenarios that aim to balance the deviations of individual units, ensuring that the average level of all units reaches the target value, thereby minimizing the overall deviation.

[0028] The target correlated color temperature is obtained by calculating the median of the correlated color temperatures of all units to be calibrated, and the target color coordinates are obtained by calculating the median of the original color coordinates of all units to be calibrated. The target correlated color temperature and target color coordinates are then used as the reference color temperature parameters. Compared to the mean, the median reference method is insensitive to outliers. When there are individual bad pixels in the units to be calibrated, using the median can prevent the target value from being skewed by these extreme values, ensuring that the calibration reference represents the true level of most units to be calibrated.

[0029] The nominal color temperature of the unit to be calibrated within the same or different levels is used as the target correlated color temperature, and the nominal original color coordinates of the unit to be calibrated within the same or different levels are used as the target color coordinates. The target correlated color temperature and target color coordinates are then determined as the reference color temperature parameters. This approach is suitable for scenarios where product design specifications must be met, such as when delivering a product and ensuring that the final color temperature of the luminaire matches the value indicated in the product manual.

[0030] The correlated color temperature that has the smallest difference from the nominal color temperature of the luminaire design is taken as the target correlated color temperature, and the original color coordinate that has the smallest difference from the nominal original color coordinate of the luminaire design is taken as the target color coordinate. The target correlated color temperature and the target color coordinate are determined as the reference color temperature parameters. This allows the calibration unit that is produced closest to the design target to be used as a sample, enabling the alignment of other calibration units.

[0031] The unit to be calibrated with the smallest DUV value is selected as the target calibration unit. The correlated color temperature corresponding to the target calibration unit is taken as the target correlated color temperature, and the original color coordinates corresponding to the target calibration unit are taken as the target color coordinates. The target correlated color temperature and target color coordinates are determined as the reference color temperature parameters. The smallest absolute DUV value means that the color of the unit to be calibrated is closest to the perfect blackbody radiation trajectory, and its light color quality is the highest, thus prioritizing the purity of the final light emitted by the lamp.

[0032] In the lamp-level calibration stage, the average value of all lamps inside a single lamp or the nominal value of the lamp is used as the target; in the lamp-level calibration stage, the average value or nominal value of all lamps in the same space is used as the target, thereby achieving both intra-lamp consistency and inter-lamp consistency.

[0033] Understandably, the above methods can be used in combination, or users can manually select one as the final benchmark determination strategy through the host computer software interface. For example, in a typical production line calibration process, the mean benchmark method can be used by default, but quality inspectors are allowed to temporarily switch to the optimal DUV method when they find that the DUV values ​​of individual LEDs in a certain lamp are abnormally high, using the LED with the purest light color in that lamp as the benchmark for calibration.

[0034] Regarding step S102 above, after determining the reference color temperature parameter, it is necessary to quantify the difference between each unit to be calibrated and this reference. In some embodiments, for the i-th unit to be calibrated, its color temperature deviation can be directly obtained by subtraction in the CIE 1931 color coordinate space: ΔCCT_i = CCT_target - CCT_i; Δx_i = x_target - x_i; Δy_i = y_target - y_i; Where CCT_i is the correlated color temperature of the i-th unit to be calibrated, x_i and y_i are the original color coordinates of the i-th calibration unit, CCT_target is the target correlated color temperature, x_target and y_target are the target color coordinates, and ΔCCT_i, Δx_i and Δy_i are the color temperature deviations.

[0035] In some embodiments, because human eye perception of chromaticity is non-linear, the CIE 1931 color coordinate space is not a uniform color space; that is, the same geometric distance in the space represents different color differences perceived by the human eye in different regions. To more accurately quantify the color differences perceptible to the human eye, refer to... Figure 2 , Figure 2 yes Figure 1 A flowchart further includes step S102. In some other embodiments, the process of determining the color temperature deviation may include steps S201 to S202: Step S201: Transform the original color coordinates and the target color coordinates to obtain the original uniform color coordinates and the target uniform color coordinates.

[0036] Specifically, the collected CIE 1931 color coordinates (x, y) are converted to CIE 1960 UCS (Uniform Color Space) uniform color coordinates (u, v). The conversion formula is as follows: u = 4x / (-2x + 12y + 3); v = 6y / (-2x + 12y + 3); Similarly, the target color coordinates (x_target, y_target) are also converted to the target uniform color coordinates (u_target, v_target).

[0037] Step S202: Determine the color temperature deviation based on the difference between the original uniform color coordinates and the target uniform color coordinates.

[0038] Within the CIE 1960 UCS color space, the perceptual difference between two colors can be approximated by the Euclidean distance between their coordinate points. Therefore, for the i-th calibration unit, its chromaticity distance D_i is calculated as follows: Δu_i = u_target - u_i; Δv_i = v_target - v_i; D_i = √(Δu_i 2 + Δv_i 2 ); In step S103 above, the compensation coefficient is used to convert the measured color temperature deviation into control commands for the luminaire driver circuit. Different compensation coefficients are generated based on the luminaire hardware architecture, driving method, and calibration level.

[0039] Reference Figure 3 , Figure 3 yes Figure 1 The flowchart further includes step S103. In some embodiments, the process of determining the compensation coefficient of each unit to be calibrated based on the color temperature deviation may include steps S301 to S302: Step S301: Determine the color temperature type of the unit to be calibrated.

[0040] The color temperature type indicates whether the unit being calibrated uses a single-color temperature LED or a dual-color temperature LED. Dual-color temperature LEDs typically consist of a cool white LED and a warm white LED packaged together, with color temperature adjusted by regulating the brightness ratio of each. Single-color temperature LEDs, on the other hand, have only one color temperature, which usually drifts within a small range with changes in the drive current.

[0041] Step S302: Determine the compensation coefficient for each unit to be calibrated based on the color temperature type and the color temperature deviation.

[0042] When the color temperature type indicates that the unit to be calibrated uses dual-color temperature LEDs, a PWM duty cycle compensation scheme is adopted. Specifically, the first duty cycle adjustment amount and the second duty cycle adjustment amount corresponding to each unit to be calibrated are determined as compensation coefficients. If the color temperature deviation indicates that the unit to be calibrated is showing a warmer color temperature, that is, the current CCT_i is lower than the target CCT_target, ΔCCT_i>0, indicating insufficient cool white component and excessive warm white component, then the first duty cycle adjustment amount is used to increase the PWM duty cycle of the cool color temperature LED to increase cool light output; the second duty cycle adjustment amount is used to decrease the PWM duty cycle of the warm color temperature LED to decrease warm light output. Conversely, if the color temperature deviation indicates that the unit to be calibrated is showing a cool color temperature, that is, the current CCT_i is higher than the target CCT_target, ΔCCT_i<0, then the first duty cycle adjustment amount is used to increase the PWM duty cycle of the warm color temperature LED, and the second duty cycle adjustment amount is used to decrease the PWM duty cycle of the cool color temperature LED.

[0043] The amount of compensation can be determined in several ways. For example, it can be obtained by looking up a pre-calibrated duty cycle color temperature mapping table. This table records the actual color temperatures achievable under standard operating conditions for different combinations of cool and warm white duty cycles. Alternatively, a linear or polynomial fitting model can be used, taking the color temperature deviation as input, to directly calculate the required duty cycle adjustment.

[0044] When the color temperature type indicates that the unit to be calibrated uses a single-color temperature LED, color temperature fine-tuning can also be performed using PWM dimming. The principle is that the color temperature of an LED is not constant, but rather drifts slightly with changes in its junction temperature and operating current. By adjusting the PWM duty cycle to change the average operating current of the LED, this drift characteristic can be used to correct the color temperature deviation. Specifically, based on the color temperature deviation, the third duty cycle adjustment amount corresponding to each unit to be calibrated is determined from a preset duty cycle color temperature mapping table as a compensation coefficient. Alternatively, for increased flexibility, the color temperature deviation can be input into a pre-trained fitting model, such as a linear regression model or a simple polynomial model, which will then calculate the required third duty cycle adjustment amount in real time.

[0045] In some embodiments, for luminaires with built-in independent drive channels, a current compensation scheme can be employed. This scheme does not rely on the PWM duty cycle but directly adjusts the drive current of each LED chip or each LED channel. Specifically, the drive current compensation amount corresponding to each unit to be calibrated is determined as a compensation coefficient from a preset current-color-temperature characteristic curve based on the color temperature deviation. The current-color-temperature characteristic curve describes the correspondence between the drive current value and the color temperature of the LED chip under specific conditions. Through piecewise linear interpolation, polynomial fitting, or lookup table methods, the accurate current value required to achieve the target color temperature can be derived from this curve. This method directly controls the physical input of the light source, thereby improving the accuracy of control.

[0046] In some embodiments, PWM compensation and current compensation can be combined to achieve two-stage calibration. Specifically, based on the color temperature deviation, the fourth duty cycle adjustment amount corresponding to each unit to be calibrated is determined from a preset duty cycle color temperature mapping table as a first compensation coefficient, used for coarse adjustment to quickly cover most of the color temperature deviation. Then, based on the color temperature deviation, the drive current compensation amount corresponding to each unit to be calibrated is determined from a preset current color temperature curve as a second compensation coefficient, used for fine adjustment after coarse adjustment based on the first compensation coefficient. The first compensation coefficient is used for coarse adjustment, and the second compensation coefficient is used for fine adjustment after coarse adjustment based on the first compensation coefficient. By adopting the above hybrid strategy, both a wide adjustment range and high calibration accuracy can be achieved.

[0047] In some embodiments, when performing lamp-level calibration, each unit to be calibrated consists of lamps with independent drive channels, and each lamp in the same lamp can be controlled individually. In this case, based on the color temperature type and the amount of color temperature deviation, a corresponding fifth duty cycle adjustment is independently determined as a compensation coefficient for each lamp. These compensation coefficients do not interfere with each other and are written into the drive channel of the corresponding lamp. After independent compensation, the light emitted by each lamp is spatially mixed within the same reflector or lens, resulting in a highly uniform color temperature in the overall light output of the lamp, eliminating color spots and color banding.

[0048] In some embodiments, multiple temperature sensors can be deployed inside the lamp, or the temperature detection function inside the driver chip can be reused to collect temperature data at each key location in real time, and dynamically calculate the real-time junction temperature of each LED bead in combination with the heat conduction model. Then, the calibration coefficient is dynamically corrected according to the pre-calibrated junction temperature color temperature drift characteristic curve.

[0049] Specifically, multiple temperature sensors are arranged on the PCB substrate of the lamp. The number and position of the sensors are determined according to the structural complexity of the lamp and the arrangement of the LED beads. Alternatively, an LED driver chip with temperature detection function can be used. The LED driver chip has built-in temperature detection and protection functions, and the approximate temperature of the LED beads driven by the driving channel can be obtained by reading the temperature value of the internal register of the chip. Through the acquisition of temperature data from multiple nodes, the temperature distribution vector T_sensor = [T_s1, T_s2, …, T_sk] of the entire lamp can be constructed.

[0050] Since temperature sensors cannot be directly mounted inside the PN junction of LED chips, a conversion model needs to be established from the temperature measured by the sensor to the junction temperature of the LED chip. Specifically, for the j-th LED chip, its junction temperature... This can be expressed as a function of the temperature of each sensor: ; in, is the driving power of the j-th LED, and t is the lighting time (characterizing the heat accumulation process from cold start). Function This can be obtained through finite element thermal simulation or experimental calibration. A simplified implementation involves linear interpolation of the sensor temperature vector combined with empirical corrections for power and time. ; in, It is a weighting coefficient, inversely proportional to the distance from the LED to the m-th sensor. It is the power temperature rise coefficient. It is a steady-state temperature rise. These are thermal time constants. These coefficients can be pre-calibrated through thermal characteristic tests before leaving the factory and stored in the lamp's EEPROM.

[0051] During normal operation of the lighting fixture, the microcontroller reads data from each temperature sensor at a certain sampling period, such as every 1 second or every 10 seconds, and substitutes it into the above model to calculate the real-time junction temperature of each LED. Then, based on the pre-calibrated junction temperature color temperature drift characteristic curve, the amount of compensation required to increase / decrease to maintain the target color temperature at that junction temperature is calculated. : ; in, It is the aforementioned compensation coefficient. It is a temperature compensation item. This is the reference temperature during factory calibration. The temperature compensation term can be calculated based on a linear or polynomial model: ; coefficient and It was obtained by fitting the color temperature drift test data of the j-th LED at different junction temperatures.

[0052] The calculated dynamic compensation coefficients are written to the drive control unit in real time to fine-tune the PWM duty cycle or drive current to compensate for color temperature drift caused by temperature changes. Since the junction temperature change of the lamp is a relatively slow thermal process, this method has a low computational load and can be implemented in real time on a low-cost MCU. Through multi-node temperature field sensing and online junction temperature calculation, refined temperature compensation for each individual LED is achieved.

[0053] In step S104 above, the calculated compensation coefficients for each unit to be calibrated are written into its corresponding control unit. The control unit can be an internal MCU of the luminaire, a register of the LED driver chip, or an EEPROM capable of storing calibration parameters. The writing operation can be performed directly on the production line using a programmer, or remotely via wired or wireless communication protocols such as DMX512, DALI, Zigbee, Wi-Fi, or Bluetooth. After writing is complete, the luminaire will adjust its operating state according to these compensation coefficients.

[0054] To ensure the calibration effect in step S105, this embodiment introduces a closed-loop verification and iteration mechanism. After applying the compensation parameters and powering on or restarting the driver, the system will re-collect the actual chromaticity parameters of each unit to be calibrated and recalculate its color temperature deviation relative to the reference color temperature parameter.

[0055] Next, it is determined whether the current color temperature deviation has reached the preset threshold requirements. These thresholds can be set according to the limits of human visual perception. For example, for intra-lamp consistency, the CCT difference can be ≤50K and the DUV difference ≤0.001. For inter-lamp consistency, the CCT difference can also be set to ≤50K and the DUV difference to ≤0.001. When the color temperature deviation meets these threshold conditions, the calibration is considered successful and the process ends.

[0056] If the color temperature deviation does not reach the threshold requirement, the system enters an iterative loop. Based on the new measurement value, the system will execute steps S103 and S104 again, recalculating the compensation coefficient according to the latest deviation and writing the new compensation coefficient back into the control unit, until the color temperature deviation successfully reaches the threshold requirement or the preset maximum number of iterations is reached. The maximum number of iterations is set to prevent, in rare cases, the calibration process from failing to converge due to hardware limitations or measurement noise, thus avoiding an infinite loop.

[0057] Through the above verification and iteration mechanism, the calibration method of this disclosure embodiment can gradually approach the target value, achieving higher accuracy and reliability than a single open-loop calibration.

[0058] The LED downlight to be calibrated is placed in the integrating sphere test system. The LED downlight integrates four COB LEDs. The host computer software sequentially illuminates the first to fourth COB LEDs via the communication interface and records the CIE 1931 color coordinates (x, y), correlated color temperature (CCT), and DUV value of each LED at its rated current. For example, the measurement data is as follows: LED chip 1: (0.38, 0.37), 4000K, DUV=0.003 LED 2: (0.39, 0.38), 3900K, DUV=0.005 LED chip 3: (0.37, 0.36), 4100K, DUV=0.001 LED chip 4: (0.40, 0.39), 3850K, DUV=0.007 The user selected the optimal DUV method as the internal calibration benchmark for the LED chips via the host computer software interface. The system compared the DUV values ​​of the four LED chips and found that LED chip 3 had the smallest absolute value of DUV=0.001, indicating the purest light color. Therefore, the system determined the actual chromaticity parameters of LED chip 3 as the benchmark. Target color coordinates: (0.37, 0.36) Target CCT: 4100K Next, the system calculates the color temperature deviation of the other three LEDs relative to LED 3.

[0059] LED bead 1: It is too warm, so the cool white component needs to be increased and the warm white component needs to be reduced.

[0060] LED bead 2: Too warm, need to increase cool white component and reduce warm white component.

[0061] LED 4: It is warm-toned and has high DUV. It is necessary to increase the cool white component, reduce the warm white component, and fine-tune the current to reduce DUV.

[0062] Since the lamp uses dual-color temperature LEDs, the system adopts a hybrid compensation scheme. First, based on the preset duty cycle color temperature mapping table, the PWM coarse adjustment coefficients are calculated for LEDs 1, 2, and 4; then, based on the remaining small deviations, the current fine adjustment coefficients are calculated from the current color temperature curve.

[0063] The system writes the calculated compensation coefficients into the driver chip registers of the four LEDs within the luminaire via the I2C bus. After writing, all LEDs are relit and measured. When the verification results show that the CCT of all four LEDs is between 4090K and 4110K, and the DUV is less than 0.002, the intraluminaire consistency requirement is met, and the first level of calibration is completed.

[0064] Next, two other lamps of the same model, B and C, from the same production line, were placed in a darkroom along with lamp A, which had undergone lamp-level calibration. These three lamps were used as the new calibration unit. The host computer software simultaneously illuminated all three lamps and measured the overall chromaticity parameters of each lamp. The measurement results are as follows: Light fixture A: (0.371, 0.361), 4110K Light fixture B: (0.365, 0.355), 4050K Light fixture C: (0.378, 0.368), 4180K The purpose of this calibration is to ensure color temperature consistency among the three luminaires, applicable to installation scenarios within the same showroom. Accordingly, the user selected the mean-based benchmark method from the host computer software interface. The system calculates the average CCT of the three luminaires to be (4110+4050+4180) / 3 = 4113.3K, and also calculates the average color coordinates. Therefore, the benchmark parameters for luminaire-level calibration are determined as follows: target CCT approximately 4113K, target color coordinates approximately (0.3713, 0.3613).

[0065] The system calculates the deviations of lamps B and C relative to the reference.

[0066] Light fixture B: Deviation -63K, warmer than normal.

[0067] Light fixture C: Deviation +67K, too cool.

[0068] During lamp-level calibration, each lamp has its own independent control system, which calculates the overall PWM duty cycle adjustment coefficient for lamps B and C respectively.

[0069] The system remotely writes the calculated luminaire-level compensation coefficients into the controllers of luminaires B and C via the DALI communication protocol. After writing, all three luminaires are simultaneously lit again and measurements are taken. Verification results show that the CCT of all three luminaires is stable between 4105K and 4120K, with a maximum CCT difference of less than 15K, far exceeding the 50K threshold requirement. Ultimately, these luminaires simultaneously meet the high-quality lighting requirements of no internal color spots and no external color temperature difference.

[0070] Reference Figure 4 , Figure 4 This is a schematic diagram of the structure of a color temperature calibration system provided in an embodiment of the present disclosure. The color temperature calibration system includes: The parameter acquisition module 401 is used to acquire the actual colorimetric parameters of each unit to be calibrated and to determine the reference color temperature parameters. The deviation determination module 402 is used to determine the color temperature deviation for each unit to be calibrated based on the difference between the actual colorimetric parameters and the reference color temperature parameters. The compensation coefficient determination module 403 is used to determine the compensation coefficient of each unit to be calibrated based on the color temperature deviation. The writing module 404 is used to write the compensation coefficients into the control unit corresponding to the unit to be calibrated. The iteration module 405 is used to re-acquire the actual chromaticity parameters of each unit to be calibrated, and determine the color temperature deviation of each unit to be calibrated again based on the actual chromaticity parameters. When the color temperature deviation does not reach the threshold requirement, the compensation coefficient of each unit to be calibrated is determined again based on the color temperature deviation and written to the control unit until the color temperature deviation reaches the threshold requirement or the maximum number of iterations is reached.

[0071] This disclosure also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described smart lock user behavior model update method.

[0072] Memory, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs. Furthermore, memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, memory may optionally include memory remotely located relative to the processor, and these remote memories can be connected to the processor via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0073] The embodiments described in this disclosure are for the purpose of more clearly illustrating the technical solutions of this disclosure and do not constitute a limitation on the technical solutions provided by this disclosure. As those skilled in the art will know, with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by this disclosure are also applicable to similar technical problems.

[0074] Those skilled in the art will understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of this disclosure, and may include more or fewer steps than shown, or combine certain steps, or different steps.

[0075] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of the embodiments disclosed herein, depending on actual needs.

[0076] Those skilled in the art will understand that all or some of the steps, apparatuses, or functional modules / units in the methods disclosed above can be implemented as software, firmware, hardware, or suitable combinations thereof.

[0077] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in this disclosure and the foregoing drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of this disclosure described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, apparatus, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0078] It should be understood that in this disclosure, "at least one item" means one or more, and "more than one" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0079] In the several embodiments provided in this disclosure, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of the units described above is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0080] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the embodiments of this disclosure, depending on actual needs.

[0081] Furthermore, the functional units in the various embodiments of this disclosure can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0082] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this disclosure, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes multiple instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this disclosure. The aforementioned storage medium includes various media capable of storing programs, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0083] The preferred embodiments of the present disclosure have been described above with reference to the accompanying drawings, but this does not limit the scope of the claims of the present disclosure. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and spirit of the present disclosure shall be within the scope of the claims of the present disclosure.

Claims

1. A color temperature calibration method, characterized in that, include: Collect the actual colorimetric parameters of each unit to be calibrated and determine the reference color temperature parameters; For each of the units to be calibrated, the color temperature deviation is determined based on the difference between the actual colorimetric parameters and the reference color temperature parameters; The compensation coefficient for each of the units to be calibrated is determined based on the color temperature deviation. Write the compensation coefficient into the control unit corresponding to the unit to be calibrated; The actual chromaticity parameters of each of the units to be calibrated are re-acquired, and the color temperature deviation of each of the units to be calibrated is determined again based on the actual chromaticity parameters. When the color temperature deviation does not reach the threshold requirement, the compensation coefficient of each of the units to be calibrated is determined again based on the color temperature deviation and written to the control unit until the color temperature deviation reaches the threshold requirement or the maximum number of iterations is reached.

2. The color temperature calibration method according to claim 1, characterized in that, The step of determining the compensation coefficient for each of the units to be calibrated based on the color temperature deviation includes: The color temperature type of the unit to be calibrated is determined, and the color temperature type is used to indicate whether the unit to be calibrated uses a single-color temperature LED or a dual-color temperature LED. The compensation coefficient for each of the units to be calibrated is determined based on the color temperature type and the color temperature deviation.

3. The color temperature calibration method according to claim 2, characterized in that, The step of determining the compensation coefficient for each of the units to be calibrated based on the color temperature type and the color temperature deviation includes: When the color temperature type indicates that the unit to be calibrated uses dual-color temperature LEDs, the first duty cycle adjustment amount and the second duty cycle adjustment amount corresponding to each unit to be calibrated are determined as compensation coefficients. If the color temperature deviation indicates that the unit to be calibrated is displaying a warmer color temperature, the first duty cycle adjustment amount is used to increase the PWM duty cycle of the cool color temperature LEDs, and the second duty cycle adjustment amount is used to decrease the PWM duty cycle of the warm color temperature LEDs. If the color temperature deviation indicates that the unit to be calibrated is displaying a cooler color temperature, the first duty cycle adjustment amount is used to increase the PWM duty cycle of the warm color temperature LEDs, and the second duty cycle adjustment amount is used to decrease the PWM duty cycle of the cool color temperature LEDs. When the color temperature type indicates that the unit to be calibrated uses a single-color temperature LED, the third duty cycle adjustment amount corresponding to each unit to be calibrated is determined from the preset duty cycle color temperature mapping table according to the color temperature deviation amount as a compensation coefficient, or the color temperature deviation amount is input into the fitting model to determine the third duty cycle adjustment amount corresponding to each unit to be calibrated as a compensation coefficient.

4. The color temperature calibration method according to claim 1, characterized in that, The step of determining the compensation coefficient for each of the units to be calibrated based on the color temperature type and the color temperature deviation includes: The driving current compensation amount corresponding to each of the units to be calibrated is determined from the preset current color temperature curve based on the color temperature deviation amount, and used as the compensation coefficient.

5. The color temperature calibration method according to claim 1, characterized in that, The step of determining the compensation coefficient for each of the units to be calibrated based on the color temperature type and the color temperature deviation includes: Based on the color temperature deviation, the fourth duty cycle adjustment amount corresponding to each of the units to be calibrated is determined from the preset duty cycle color temperature mapping table as the first compensation coefficient. The driving current compensation amount corresponding to each of the units to be calibrated is determined from the preset current color temperature curve based on the color temperature deviation amount as the second compensation coefficient. The first compensation coefficient is used for coarse adjustment, and the second compensation coefficient is used for fine adjustment after coarse adjustment based on the first compensation coefficient.

6. The color temperature calibration method according to claim 1, characterized in that, Each of the units to be calibrated is a lamp bead with an independent driving channel. Determining the compensation coefficient for each unit to be calibrated based on the color temperature type and the color temperature deviation includes: The fifth duty cycle adjustment amount corresponding to each of the units to be calibrated is determined as a compensation coefficient based on the color temperature type and the color temperature deviation.

7. The color temperature calibration method according to claim 1, characterized in that, The actual chromaticity parameters include the original chromaticity coordinates, correlated color temperature, and DUV values, and the parameters for determining the reference color temperature include at least one of the following: The target correlated color temperature is obtained by calculating the mean value of the correlated color temperature of all units to be calibrated in the same or different levels, and the target color coordinates are obtained by calculating the mean value of the original color coordinates of all units to be calibrated in the same or different levels. The target correlated color temperature and the target color coordinates are determined as reference color temperature parameters. The target correlated color temperature is obtained by calculating the median of the correlated color temperatures of all the units to be calibrated, and the target color coordinates are obtained by calculating the median of the original color coordinates of all the units to be calibrated. The target correlated color temperature and the target color coordinates are determined as reference color temperature parameters. The nominal color temperature of the unit to be calibrated in the same or different levels is used as the target correlated color temperature, and the nominal original color coordinates of the unit to be calibrated in the same or different levels are used as the target color coordinates. The target correlated color temperature and the target color coordinates are determined as the reference color temperature parameters. The correlated color temperature with the smallest difference from the nominal color temperature of the luminaire design is taken as the target correlated color temperature, and the original color coordinate with the smallest difference from the nominal original color coordinate of the luminaire design is taken as the target color coordinate. The target correlated color temperature and the target color coordinate are determined as the reference color temperature parameters. The unit to be calibrated with the smallest DUV value is taken as the target calibration unit, the correlated color temperature corresponding to the target calibration unit is taken as the target correlated color temperature, the original color coordinates corresponding to the target calibration unit are taken as the target color coordinates, and the target correlated color temperature and the target color coordinates are determined as the reference color temperature parameters.

8. The color temperature calibration method according to claim 1, characterized in that, The actual chromaticity parameters include original chromaticity coordinates, and the reference chromaticity parameters include target chromaticity coordinates. Determining the color temperature deviation based on the difference between the actual chromaticity parameters and the reference color temperature parameters includes: The original color coordinates and the target color coordinates are transformed to obtain the original uniform color coordinates and the target uniform color coordinates respectively; The color temperature deviation is determined based on the difference between the original uniform color coordinates and the target uniform color coordinates.

9. A color temperature calibration system, characterized in that, include: The parameter acquisition module is used to acquire the actual colorimetric parameters of each unit to be calibrated and determine the reference color temperature parameters. The deviation determination module is used to determine the color temperature deviation for each of the units to be calibrated based on the difference between the actual colorimetric parameters and the reference color temperature parameters. The compensation coefficient determination module is used to determine the compensation coefficient of each of the units to be calibrated based on the color temperature deviation. The writing module is used to write the compensation coefficient into the control unit corresponding to the unit to be calibrated; The iteration module is used to re-acquire the actual chromaticity parameters of each of the units to be calibrated, and determine the color temperature deviation of each of the units to be calibrated again based on the actual chromaticity parameters. When the color temperature deviation does not reach the threshold requirement, the compensation coefficient of each of the units to be calibrated is determined again based on the color temperature deviation and written to the control unit until the color temperature deviation reaches the threshold requirement or the maximum number of iterations is reached.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the color temperature calibration method according to any one of claims 1 to 8.

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