Method and circuit for improving consistency of illumination intensity of light supplement lamp of video monitoring equipment

Abstract

The invention provides a method for improving consistency of illumination intensity of a light supplement lamp of video monitoring equipment, and belongs to the technical field of video security monitoring, and the method comprises the steps: obtaining preset configuration parameters of the light supplement lamp of the video monitoring equipment, including a PWM signal preset value used for controlling the light supplement lamp, a voltage value corresponding to the PWM signal preset value, and a maximum working current value; obtaining a current illumination value of the video monitoring equipment based on the preset configuration parameters of the light supplement lamp, and obtaining an illumination coefficient according to the current illumination value and the theoretical illumination value under the condition that the maximum illumination is started; obtaining a PWM signal control value of the light supplement lamp according to the PMW signal preset value of the light supplement lamp and the illumination coefficient; acquiring a light supplement lamp sampling voltage based on the PWM signal control value, judging whether the sampling voltage meets requirements or not, if the sampling voltage meets the requirements, maintaining the current PMW signal control value of the light supplement lamp, if the sampling voltage does not meet the requirements, adjusting the illumination coefficient to obtain a new PWM signal control value of the light supplement lamp, and re-acquiring the sampling voltage of the light supplement lamp under the new PMW signal control value; and the sampling voltage meets the requirement.

Description

Technical Field

[0001] This application belongs to the technical field of video security monitoring, and particularly relates to a method and circuit for improving the illuminance consistency of supplementary lights of video monitoring devices. Background Art

[0002] In the field of security, infrared lights and white lights are key supplementary lighting technology components used to enhance the visual capabilities of surveillance cameras in different environments. Among them, infrared lights (IR), also known as night vision infrared lights, are supplementary lighting devices that cooperate with surveillance cameras to capture images at night. They sense infrared rays, with a wavelength range of 800nm - 1100nm, enabling 24-hour continuous monitoring of the monitored area without lighting. The working principle of infrared light supplementary lighting is that the infrared light irradiates an object, and the infrared rays undergo diffuse reflection and are received by the infrared surveillance camera to form a video image. White lights (WLED), also known as visible light lamps, are supplementary lighting devices that provide visible light illumination at night. White lights are suitable for scenarios that require clear and high-brightness images, such as license plate recognition. The lighting effect of white lights is directly visible and does not produce red glow. Compared with infrared lights, the image quality of white light supplementary lighting is clearer, but it may expose the position in some applications.

[0003] The monitoring devices of the prior art mainly have the following problems in terms of the illuminance of supplementary lights:

[0004] 1) Insufficient current accuracy: The current control of the supplementary lights in the prior art is usually not precise enough, resulting in unstable image brightness, which may affect the performance of the monitoring system and the image quality.

[0005] 2) Poor product consistency: The monitoring devices of the prior art do not have the function of monitoring supplementary lights, resulting in inconsistent monitoring quality of the monitoring devices, manifested as a relatively dispersed normal distribution and an insufficiently concentrated central value.

[0006] 3) Service life and temperature rise problems: Uncertain current values may cause premature damage to the supplementary light components, thereby shortening the service life of some products. In addition, unstable current may also cause the supplementary lights to overheat, affecting the overall product performance and user experience.

[0007] 4) Image quality differences: Inconsistent current values (temperature rise) will result in inconsistent image quality under supplementary lighting conditions, affecting the monitoring effect and indirectly affecting the standby time of the product. Summary of the Invention

[0008] The purpose of this application is to provide a method and circuit for improving the illuminance consistency of supplementary lights of video monitoring devices to solve or mitigate at least one problem in the background art.

[0009] The technical solution of this application is: a method for improving the illumination intensity consistency of the supplementary light of a video surveillance device, including:

[0010] Obtain the preset configuration parameters of the supplementary light of the video surveillance device, where the preset configuration parameters include the preset value of the PWM signal for controlling the supplementary light, the voltage value corresponding to the preset value of the PWM signal, and the maximum operating current value;

[0011] Obtain the current illumination value of the video surveillance device based on the preset configuration parameters of the supplementary light, and obtain the illumination coefficient according to the current illumination value and the theoretical illumination value under the maximum illumination;

[0012] Obtain the PWM signal control value of the supplementary light according to the preset value of the PMW signal of the supplementary light and the illumination coefficient;

[0013] Obtain the sampled voltage of the supplementary light based on the PWM signal control value, and determine whether the sampled voltage meets the requirements. When it meets the requirements, maintain the current PMW signal control value of the supplementary light. When it does not meet the requirements, adjust the illumination coefficient to obtain a new PWM signal control value of the supplementary light, and re-obtain the sampled voltage under the new PWM signal control value of the supplementary light until the sampled voltage meets the requirements.

[0014] Preferably, the supplementary light includes one or a combination of an infrared supplementary light, a visible light supplementary light, and a multi-spectral supplementary light.

[0015] Preferably, the illumination coefficient is the ratio of the current illumination value to the theoretical illumination value or the reciprocal of the ratio of the current illumination value to the theoretical illumination value.

[0016] Preferably, the PWM signal control value satisfies:

[0017] PWM_c = PWM_d * β * η,

[0018] In the formula, PWM_c is the PWM signal control value of the supplementary light, PWM_d is the preset value of the PMW signal of the supplementary light, β is the current coefficient, and η is the illumination coefficient.

[0019] Preferably, the current coefficient is the ratio of the actual value to the theoretical value of the maximum operating current of the supplementary light.

[0020] Preferably, the method for determining whether the sampled voltage meets the requirements is:

[0021] Determine whether the sampled voltage is equal to the product of the voltage value in the preset configuration parameters and the illumination coefficient. If they are equal, it meets the requirements. If they are not equal, it does not meet the requirements.

[0022] Preferably, it further includes:

[0023] Obtain the operating temperature of the fill light of the video surveillance device and the maximum operating temperature threshold, and determine whether the operating temperature of the fill light exceeds the maximum operating temperature threshold. If it does not exceed, maintain the current PWM signal control value of the fill light. If it exceeds, adjust the illumination coefficient and obtain the new PWM signal control value of the fill light, and re-obtain the operating temperature under the new PWM signal control value of the fill light until the operating temperature does not exceed the maximum operating temperature threshold.

[0024] Preferably, it further includes:

[0025] Judge whether the image quality obtained by the video surveillance device meets the usage requirements of the video surveillance device. If the obtained image quality meets the usage requirements, maintain the current PWM signal control value of the fill light; if the image quality does not meet the usage requirements, adjust the illumination coefficient and obtain the new PWM signal control value of the fill light, and re-obtain the image under the new PWM signal control value of the fill light until the obtained image quality meets the usage requirements.

[0026] In addition, the present application also provides a circuit for implementing the method for improving the illumination intensity consistency of the fill light of the video surveillance device described in any one of the above. The circuit includes:

[0027] A data processing device;

[0028] A fill light driver, which is connected to the data processing device and the fill light, and is used to drive the fill light to work under the control of the data processing device;

[0029] One or more fill lights connected in series, one end of which is connected to the fill light driver and the other end is grounded;

[0030] A sampling resistor, which is connected in series with the fill light and is used to obtain the sampling voltage of the fill light;

[0031] A temperature sensor, which is connected to the analog-to-digital conversion module and is used to collect the operating temperature of the fill light;

[0032] An analog-to-digital conversion module, which is connected to the data processing device, the sampling resistor and the temperature sensor, and is used to perform analog-to-digital conversion on the sampling voltage of the fill light and the operating temperature collected by the temperature sensor and send it to the data processing device.

[0033] Preferably, the analog-to-digital conversion module communicates with the data processing device through an I2C or SPI bus.

[0034] The method of the present application can accurately control feedback regulation, batch adaptively adjust the intensity of the fill light of the monitoring device, so as to achieve high consistency, and can realize monitoring regulation during the entire product life cycle. Description of the Drawings

[0035] To more clearly illustrate the technical solution provided in this application, the accompanying drawings will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application.

[0036] Figure 1 It is a schematic diagram of the method for improving the illumination intensity consistency of the supplementary light of the video surveillance device in this application.

[0037] Figure 2 It is a schematic circuit diagram of an embodiment of this application. Detailed implementation manners

[0038] To make the purpose, technical solution and advantages of the implementation of this application clearer, the technical solution in the embodiment of this application will be described in more detail below in conjunction with the accompanying drawings in the embodiment of this application.

[0039] To overcome the problems proposed in the background technology, this application provides a method and a circuit for improving the illumination intensity consistency of the supplementary light of the video surveillance device.

[0040] As Figure 1 shown, the method for improving the illumination intensity consistency of the supplementary light of the video surveillance device provided in this application includes the following processes:

[0041] Step S100, obtaining the preset configuration parameters of the supplementary light of the video surveillance device, where the preset configuration parameters include the preset value of the PWM (Pulse Width Modulation) signal, the voltage value corresponding to the preset value of the PWM signal, and the maximum working current value.

[0042] In the preferred embodiment of this application, the supplementary light of the video surveillance device usually includes one or a combination of an infrared supplementary light (IR), a visible light supplementary light (WLED), and a multi-spectral supplementary light. The following embodiments of this application take the supplementary light of the video surveillance device as an infrared supplementary light and a visible light supplementary light as an example for illustration. Therefore, the preset configuration parameters of the supplementary light of the video surveillance device in this embodiment include the preset value of the infrared PWM signal PWM_IR for the infrared supplementary light and the preset value of the visible light PWM signal PWM_WLED for the visible light supplementary light, as well as the infrared voltage value V corresponding to the preset value of the infrared PWM signal IR 、the infrared maximum working current value I max_IR and the visible light voltage value V corresponding to the preset value of the visible light PWM signal PWM_WLED WLED 、the visible light maximum working current value I max_WLED .

[0043] In this application, each video surveillance device will undergo an initial calibration process before leaving the factory. Different voltage values of the supplementary lights can be obtained according to the preset value of the maximum PWM signal. By setting a sampling resistor on the supplementary light, the maximum working current of the supplementary light corresponding to each video surveillance device can be calculated.

[0044] For example, in the infrared supplementary light and visible light supplementary light embodiments of this application, the infrared voltage value V of the infrared supplementary light can be obtained according to the preset value of the maximum PWM signal IR and the visible light voltage value V of the visible light supplementary light WLED . By respectively setting an infrared sampling resistor R_FB1 and a visible light sampling resistor R_FB2 on the infrared supplementary light and the visible light supplementary light, the maximum working currents of the infrared supplementary light and the visible light supplementary light in each video surveillance device can be obtained, that is:

[0045] I max_IR =V IR / R_FB1, I max_WLED =V WLED / R_FB2.

[0046] The maximum working currents of the infrared supplementary light and the visible light supplementary light of video surveillance devices of the same model are determined during design. If the maximum working current of a certain supplementary light calculated through the above process is less than the theoretical value, this video surveillance device is an abnormal video surveillance device and cannot leave the factory; similarly, exceeding the maximum upper limit of the theoretical value also belongs to an abnormal video surveillance device.

[0047] Step S200: Obtain the current illuminance value Lux1 of the video surveillance device based on the preset configuration parameters, and obtain the illuminance coefficient η according to the current illuminance value Lux1 and the theoretical illuminance value Lux0 under the maximum illumination.

[0048] In some embodiments of this application, the illuminance coefficient η can be the ratio of the current illuminance value Lux1 to the theoretical illuminance value Lux0 under the maximum illumination, or the illuminance coefficient η can be the reciprocal of the ratio of the theoretical current illuminance value Lux1 to the theoretical illuminance value Lux0 under the maximum illumination.

[0049] Step S300: Obtain the PWM signal control value of the supplementary light according to the PMW signal preset value of the supplementary light and the illuminance coefficient η.

[0050] Among them, the PMW signal preset value of the supplementary light, the illuminance coefficient η and the PWM signal control value of the supplementary light satisfy the following relationship:

[0051] PWM_c = PWM_d * β * η

[0052] Wherein, PWM_c is the PWM signal control value of the supplementary light, PWM_d is the preset value of the PMW signal of the supplementary light, β is the current coefficient, and η is the illuminance coefficient. Among them, the current coefficient β is the ratio of the actual value to the theoretical value of the maximum working current of the supplementary light.

[0053] For the video surveillance equipment of good quality, the actual maximum working current of each video surveillance equipment will show a normal distribution. In this application, the ratio between the actual value and the theoretical value of the maximum working current is denoted as the current coefficient β, so that the current coefficient β of each video surveillance equipment is different, while the maximum working current (I max_IR or I max_WLED ) × the current coefficient β is a unified theoretical value.

[0054] For example, in this embodiment of the present application, according to the infrared PMW signal preset value PWM_IR of the infrared supplementary light or the visible light PMW signal preset value PWM_WLED of the visible light supplementary light and the illuminance coefficient η, the PMW signal control value (PWM1 or PWM2) of the corresponding supplementary light can be obtained. PWM1 is the infrared PWM signal control value obtained according to the infrared PMW signal preset value, and PWM2 is the visible light PWM signal control value obtained according to the visible light PWM signal preset value, that is:

[0055] PWM1 = PWM_IR * current coefficient β * illuminance coefficient η

[0056] PWM2 = PWM_WLED * current coefficient β * illuminance coefficient η.

[0057] Step S400, obtain the sampling voltage of the supplementary light based on the PWM signal control value, and judge whether the sampling voltage of the supplementary light meets the requirements. If it meets the requirements, maintain the current PWM signal control value of the supplementary light. If it does not meet the requirements, adjust the illuminance coefficient and obtain the new PWM signal control value of the supplementary light, and re-obtain the sampling voltage under the new PWM signal control value of the supplementary light until the sampling voltage meets the requirements.

[0058] In this application, the method for judging whether the sampling voltage of the supplementary light meets the requirements is: judge whether the sampling voltage is equal to the product of the voltage value in the preset configuration parameter and the illuminance coefficient. If they are equal, it meets the requirements; if not, it does not meet the requirements.

[0059] For example, in this embodiment of the present application, the sampling voltages of the infrared supplementary light and the visible light supplementary light are V1 and V2 respectively. Judge whether the sampling voltage V1 is equal to the infrared voltage value V IR * illuminance coefficient η or whether the sampling voltage V2 is equal to the visible light voltage value V WLED*Illumination coefficient η, when they are equal, maintain the current PWM signal control values PWM1 and PWM2 of the corresponding supplementary light; if they are not equal, adjust the illumination coefficient and repeat the above process.

[0060] In addition, the method of the present application further includes:

[0061] S500, obtain the operating temperature of the supplementary light of the video surveillance device and the maximum operating temperature threshold, and determine whether the operating temperature of the supplementary light exceeds the maximum operating temperature threshold of the supplementary light. If it does not exceed (i.e., less than or equal to), maintain the current PWM signal control value of the supplementary light until the supplementary light ends its operation; if it exceeds (i.e., greater than), adjust the illumination coefficient and obtain the new PWM signal control value of the supplementary light, and re-obtain the operating temperature under the new PWM signal control value of the supplementary light until the operating temperature does not exceed the maximum operating temperature threshold.

[0062] Finally, the method of the present application further includes:

[0063] Step S600, determine whether the image quality obtained by the video surveillance device meets the usage requirements of the video surveillance device. If the image quality meets the requirements, maintain the current PWM signal control value of the supplementary light until the operation ends; if the image quality does not meet the usage requirements, adjust the illumination coefficient and obtain the new PWM signal control value of the supplementary light, and re-obtain the image under the new PWM signal control value of the supplementary light until the obtained image quality meets the usage requirements.

[0064] In some embodiments of the present application, to determine whether the image quality obtained by the video surveillance device meets the usage requirements of the video surveillance device, it can be determined by judging whether the overall gray value of the obtained image is greater than the threshold. If the overall gray value of the image is greater than the threshold, it indicates that the image is brighter, and the image obtained by the supplementary light can meet the usage requirements; otherwise, it does not meet the requirements.

[0065] On the other hand, the present application provides a circuit for implementing the method for achieving the illumination intensity consistency of the supplementary light of the video surveillance device described above. The circuit includes:

[0066] A data processing device, which is a device or equipment with data processing capabilities or code execution capabilities. For example, the data processing device can be a microcontroller (MCU) or a system-on-chip (SoC System), and specific application programs can be executed through the microcontroller or the system-on-chip, etc.;

[0067] A supplementary light driver, which is connected to the data processing device and the supplementary light, and is used to drive the supplementary light to work under the control of the data processing device;

[0068] One or more supplementary lights connected in series, with one end connected to the supplementary light driver and the other end grounded;

[0069] A sampling resistor, which is arranged between the fill light and the ground terminal and is connected in series with the fill light, for obtaining the sampling voltage of the fill light;

[0070] A temperature sensor, which is connected to the analog-to-digital conversion module, for collecting the operating temperature of the fill light;

[0071] An analog-to-digital conversion module, which is connected to the data processing device, the sampling resistor and the temperature sensor, for converting the sampling voltage and the operating temperature collected by the temperature sensor into digital signals and sending them to the data processing device.

[0072] As Figure 2 shown is the circuit including the infrared fill light and the visible light fill light in this embodiment of the present application. The circuit board includes:

[0073] A data processing device 10;

[0074] An infrared fill light driver 21 and a visible light driver 22. The infrared fill light driver 21 is connected to the data processing device 10 and the infrared fill light 31, for driving the infrared fill light 31 to work under the control of the data processing device 10. The visible light driver 22 is connected to the data processing device 10 and the visible light fill light 32, for driving the visible light fill light 32 to work under the control of the data processing device 10;

[0075] Multiple infrared fill lights 31 and multiple visible light fill lights 32. The multiple infrared fill lights are connected in series and one end thereof is connected to the infrared fill light driver 21 and the other end is grounded. The multiple visible light fill lights are connected in series and one end thereof is connected to the visible light driver 22 and the other end is grounded;

[0076] A first sampling resistor 41 and a second sampling resistor 42. The first sampling resistor 41 is connected in series with the infrared fill light 31 and is arranged between the infrared fill light 31 and the ground terminal. The second sampling resistor 42 is connected in series with the visible light fill light 32 and is arranged between the visible light fill light 32 and the ground terminal;

[0077] A temperature sensor 60, which is connected to the analog-to-digital conversion module 60, for collecting the operating temperatures of the infrared fill light 21 and the visible light fill light 22;

[0078] An analog-to-digital conversion module 50, which is connected to the data processing device 10, the first sampling resistor 41, the second sampling resistor 42 and the temperature sensor 60, for performing analog-to-digital conversion on the sampling voltages of the first sampling resistor 41 and the second sampling resistor 42 and the operating temperatures of the infrared fill light 21 and the visible light fill light 22 and sending them to the data processing device 10.

[0079] The data processing device 10 in this application can achieve the consistency of the illumination intensity of the supplementary light of the video surveillance device by executing the above method for improving the illumination intensity consistency of the supplementary light of the video surveillance device. After responding to the action of enabling the supplementary light and turning on any supplementary light according to a preset value, the working states of each supplementary light are obtained in real time, and then a real-time adjustment instruction response is made until a relatively stable state is reached.

[0080] In some embodiments of this application, the digital-to-analog conversion module 50 can communicate with the data processing device 10 through the I2C or SPI bus.

[0081] The method and circuit of this application can accurately control the feedback adjustment and batch adaptively adjust the intensity of the supplementary light of the surveillance device, so as to achieve a high degree of consistency, and can realize the monitoring adjustment during the complete product life cycle.

[0082] The above is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in this application should be covered by the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

1. A method for improving the consistency of the illumination intensity of supplementary light of a video surveillance device, characterized in that, Including: Obtain the preset configuration parameters of the supplementary light of the video surveillance device, where the preset configuration parameters include the preset value of the PWM signal for controlling the supplementary light, the voltage value corresponding to the preset value of the PWM signal, and the maximum working current value; Obtain the current illuminance value of the video surveillance device based on the preset configuration parameters of the supplementary light, and obtain the illuminance coefficient according to the current illuminance value and the theoretical illuminance value under the maximum light on; Obtain the PWM signal control value of the supplementary light according to the preset value of the PMW signal of the supplementary light and the illuminance coefficient; Obtain the sampling voltage of the supplementary light based on the PWM signal control value, and determine whether the sampling voltage meets the requirements. When it meets the requirements, maintain the current PMW signal control value of the supplementary light. When it does not meet the requirements, adjust the illuminance coefficient to obtain the new PWM signal control value of the supplementary light, and re-obtain the sampling voltage under the new PMW signal control value of the supplementary light until the sampling voltage meets the requirements.

2. The method for improving the illumination intensity consistency of the supplementary light of a video surveillance device as described in claim 1, characterized in that, The supplementary light includes one or a combination of an infrared supplementary light, a visible light supplementary light, and a multi-spectral supplementary light.

3. The method for improving the consistency of the illumination intensity of the supplementary light of a video surveillance device according to claim 2, characterized in that, The illuminance coefficient is the ratio of the current illuminance value to the theoretical illuminance value or the reciprocal of the ratio of the current illuminance value to the theoretical illuminance value.

4. The method for improving the consistency of the illumination intensity of the supplementary light of a video surveillance device according to claim 3, characterized in that, The PWM signal control value satisfies: PWM_c = PWM_d * β * η, wherein, PWM_c is the PWM signal control value of the supplementary light, PWM_d is the preset value of the PMW signal of the supplementary light, β is the current coefficient, and η is the illuminance coefficient.

5. The method for improving the illumination intensity consistency of the supplementary light of a video surveillance device according to claim 4, characterized in that, The current coefficient is the ratio of the actual value to the theoretical value of the maximum working current of the supplementary light.

6. The method for improving the illumination intensity consistency of the supplementary light of a video surveillance device as claimed in claim 5, wherein The method for determining whether the sampling voltage meets the requirements is: Determine whether the sampling voltage is equal to the product of the voltage value in the preset configuration parameters and the illuminance coefficient. If they are equal, it meets the requirements. If they are not equal, it does not meet the requirements.

7. The method for improving the illumination intensity consistency of the supplementary light of a video surveillance device according to any one of claims 1 to 6, characterized in that Also including: Obtain the working temperature of the supplementary light of the video surveillance device and the maximum working temperature threshold, and determine whether the working temperature of the supplementary light exceeds the maximum working temperature threshold. If it does not exceed, maintain the current PWM signal control value of the supplementary light. If it exceeds, adjust the illuminance coefficient and obtain the new PWM signal control value of the supplementary light, and re-obtain the working temperature under the new PWM signal control value of the supplementary light until the working temperature does not exceed the maximum working temperature threshold.

8. The method for improving the consistency of the illumination intensity of the supplementary light of a video surveillance device according to claim 7, wherein Also including: Determine whether the image quality obtained by the video surveillance device meets the usage requirements of the video surveillance device. If the obtained image quality meets the usage requirements, maintain the current PWM signal control value of the supplementary light; If the image quality does not meet the usage requirements, adjust the illuminance coefficient and obtain the new PWM signal control value of the supplementary light, and re-obtain the image under the new PWM signal control value of the supplementary light until the obtained image quality meets the usage requirements.

9. A circuit for implementing the method for improving the consistency of the illumination intensity of the supplementary light of a video surveillance device as described in any one of claims 1 to 8, characterized in that, The circuit includes: A data processing device; A supplementary light driver, which is connected to the data processing device and the supplementary light, and is used to drive the supplementary light to work under the control of the data processing device; One or more supplementary lights, one end of which is connected to the supplementary light driver and the other end is grounded; A sampling resistor, which is arranged between the supplementary light and the ground terminal and is used to obtain the sampling voltage of the supplementary light; A temperature sensor, which is connected to the analog-to-digital conversion module and is used to collect the working temperature of the supplementary light; A digital-to-analog conversion module, which is connected to a data processing device, a sampling resistor and a temperature sensor, and is used for performing digital-to-analog conversion on the sampling voltage of the fill light and the operating temperature collected by the temperature sensor and sending the converted results to the data processing device.

10. The circuit according to claim 9, wherein The digital-to-analog conversion module communicates with the data processing device through an I2C or SPI bus.

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