Light source dimming system

Abstract

The invention relates to a light source dimming system. The system comprises an image acquisition module which is used for acquiring a target image; the control module is connected with the image acquisition module, processes the target image to obtain the current brightness of the target image, and outputs a control signal based on the current brightness of the target image; the dimming circuit is connected with the control module; the dimming circuit comprises a light source; the dimming circuit controls the average current of the light source based on the control signal to adjust the illumination intensity of the light source. The method can improve the adjustability of the brightness of the light source.

Description

Technical Field

[0001] The present application relates to the field of control technology, and in particular to a light source dimming system. Background Art

[0002] With the development of navigation and positioning technology, AR (Augmented Reality) glasses have emerged, which are mainly used in neurosurgery, spinal surgery, etc. AR glasses can capture infrared targets through infrared cameras for navigation and positioning to determine the location of the lesion. The intensity of infrared light in different environments is different. When the intensity of infrared light is not enough, an infrared light source is needed to supplement the brightness. However, the brightness of the infrared light source in the current solution is often constant and cannot adapt to different surgical environments.

[0003] The current light source dimming method or traditional method has the problem of poor adjustability of light source brightness. Summary of the invention

[0004] Based on this, it is necessary to provide a light source dimming system that can improve the adjustability of the light source brightness in order to address the above technical issues.

[0005] The present application provides a light source dimming system, the system comprising:

[0006] An image acquisition module, the image acquisition module is used to acquire a target image;

[0007] A control module, the control module is connected to the image acquisition module, the control module processes the target image, obtains the current brightness of the target image, and outputs a control signal based on the current brightness of the target image;

[0008] A dimming circuit is connected to the control module; the dimming circuit includes a light source; the dimming circuit controls an average current of the light source based on a control signal to adjust the light intensity of the light source.

[0009] In one embodiment, the dimming circuit further includes:

[0010] A driving module, the driving module includes a sampling element and a switching element; the input end of the driving module is used to connect to the power supply; the output end of the driving module is connected to the light source;

[0011] A sampling module, the sampling module is connected to the sampling element; the sampling module samples the current flowing through the sampling element and outputs a sampling signal;

[0012] The control module is connected to the sampling module and the control end of the switch element; the control module receives the sampling signal and outputs a control signal based on the sampling signal for adjusting the PWM frequency and / or duty cycle of the switch element.

[0013] In one of the embodiments, the control module outputs a control signal for increasing the PWM frequency and / or duty cycle of the switching element when the current brightness of the target image is less than or equal to a preset value;

[0014] When the current brightness of the target image is greater than a preset value, the control module outputs a control signal for reducing the PWM frequency and / or the duty cycle of the switching element.

[0015] In one embodiment, the control module includes:

[0016] A comparison unit, the comparison unit is connected to the sampling module; the comparison unit receives the sampling signal and outputs a comparison signal based on a preset threshold and the sampling signal;

[0017] The operation circuit is connected to the comparison unit and the control end of the switch element; the operation circuit receives the comparison signal and outputs the control signal based on the PWM signal and the comparison signal; the PWM signal is the current brightness setting of the control module based on the target image.

[0018] In one embodiment, the input end of the switch element is used to access the power supply; the driving module further includes:

[0019] An inductor, one end of which is connected to an output end of the switching element;

[0020] A unidirectional conductive element, wherein the current output end of the unidirectional conductive element is connected to the output end of the switch element; and the current input end of the unidirectional conductive element is also used for grounding;

[0021] A capacitor, one end of the capacitor is connected to the other end of the inductor; the other end of the capacitor is connected to one end of the sampling element; the other end of the sampling element is connected to the current input end of the unidirectional conductive element.

[0022] In one embodiment, the comparison unit comprises:

[0023] A comparator, one input end of the comparator is used to access a voltage source with a preset threshold; the other input end of the comparator is connected to a sampling module to receive a sampling signal; and the output end of the comparator outputs a comparison signal obtained by comparing the preset threshold and the sampling signal.

[0024] In one embodiment, the operation circuit includes:

[0025] An AND gate circuit, one input end of the AND gate circuit is connected to a comparison unit to receive a comparison signal; another input end of the AND gate circuit is connected to a PWM signal; an output end of the AND gate circuit is connected to a control end of a switch element to output a control signal.

[0026] In one embodiment, the image acquisition module includes an infrared camera; the light source includes an infrared light emitting diode.

[0027] In one embodiment, the sampling element includes a sampling resistor.

[0028] In one embodiment, there is a delay time between the input terminal of the comparator and the output terminal of the comparator.

[0029] The above-mentioned light source dimming system includes: an image acquisition module, the image acquisition module is used to acquire a target image, and the target image can be used to reflect the ambient brightness under the current light source conditions; a control module, the control module is connected to the image acquisition module, the control module processes the target image, obtains the current brightness of the target image, and outputs a control signal based on the current brightness of the target image; a dimming circuit, the dimming circuit is connected to the control module; the dimming circuit includes a light source; the dimming circuit controls the average current of the light source based on the control signal to adjust the light intensity of the light source. The above-mentioned light source dimming system can realize real-time adjustment of the light intensity of the light source, which can be used not only for brightness adjustment of visible light sources, but also for brightness adjustment of invisible light sources, thereby improving the fill light effect of the light source to meet the light intensity requirements in the current environment, so that the image acquisition module can acquire a clear image that meets the brightness requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a structural block diagram of a light source dimming system in an embodiment;

[0031] Figure 2 is a structural block diagram of a light source dimming system in another embodiment;

[0032] Figure 3 is a structural block diagram of a light source dimming system in yet another embodiment;

[0033] Figure 4 is a circuit diagram of a light source dimming system in one embodiment;

[0034] Figure 5 It is a structural block diagram of a light source dimming system in an example;

[0035] Figure 6 A dimming flow chart of a light source dimming system in an example;

[0036] Figure 7a is a schematic diagram of the average current of a light source in an example;

[0037] Figure 7b is a schematic diagram of the average current of a light source in another example;

[0038] Figure 7c is a schematic diagram of the average current of a light source in yet another example;

[0039] Figure 8 FIG. 4 is an internal structure diagram of a control module in an embodiment. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0041] It should be noted that current AR (Augmented Reality) devices (e.g., AR glasses) can be used in neurosurgery and spinal surgery. AR devices can capture infrared targets through infrared cameras for navigation and positioning to determine the target site of surgery. The infrared light intensity in different environments is different. When the infrared light intensity is insufficient, the system needs an infrared light source to supplement the brightness. However, the brightness of the infrared light source currently used is often constant and cannot adapt to different surgical environments.

[0042] At present, the brightness adjustment of light sources is often achieved by utilizing the principle of visual persistence of visible light sources in the human eye. Through the PWM (Pulse Width Modulation) waveform, the flickering of each lamp bead of the light source is controlled in a very short time to adjust the brightness of the light source. For example, when different lamp beads have the same light intensity, one lamp bead remains always on, and the other lamp bead remains on for 1us and off for 1us in a cycle. The brightness of the always-on lamp bead perceived by the human eye is twice the brightness of the other lamp bead. However, infrared cameras do not have the phenomenon of visual persistence, and the method of dimming the visible light source through PWM waves is not applicable to infrared light sources. Based on this, the present application provides a light source dimming system that can improve the adjustability of light source brightness.

[0043] In one embodiment, a light source dimming system is provided, such as Figure 1 As shown, the system comprises:

[0044] An image acquisition module 110, the image acquisition module 110 is used to acquire a target image;

[0045] A control module 120, the control module 120 is connected to the image acquisition module 110, the control module 120 processes the target image, obtains the current brightness of the target image, and outputs a control signal based on the current brightness of the target image;

[0046] The dimming circuit 130 is connected to the control module 120 ; the dimming circuit 130 includes a light source 132 ; the dimming circuit 130 controls an average current of the light source 132 based on a control signal to adjust the light intensity of the light source 132 .

[0047] Specifically, the image acquisition module 110 can acquire a target image, wherein the image acquisition module 110 can include at least one of a visible light camera and an invisible light camera, and the target image can be used to reflect the ambient brightness under the current light source 132 condition; the control module 120 can be connected to the image acquisition module 110 to acquire the target image and process the target image to obtain the current brightness of the target image, for example, the target image can be grayed to obtain a grayscale image of the target image, and the current brightness of the target image can be obtained by obtaining the mean and variance of the target image. Further, the control module 120 can output a control signal based on the current brightness of the target image, for example, the current brightness of the target image can be compared with the preset brightness to obtain the difference between the current brightness of the target image and the preset brightness, and output a control signal based on the current brightness of the target image and the preset brightness. The control module 120 can be connected to the dimming circuit 130 to output a control signal to the dimming circuit 130. The dimming circuit 130 can control the average current of the light source 132 based on the control signal, thereby adjusting the light intensity of the light source 132, wherein the light source 132 can include at least one of a visible light source and an invisible light source. Through the above-mentioned light source dimming system, the target image can be acquired through the image acquisition module 110, the control module 120 processes the target image to output a control signal, and the dimming circuit 130 controls the average current of the light source 132 based on the control signal, thereby achieving real-time adjustment of the light intensity of the light source 132, improving the fill light effect of the light source 132 to meet the light intensity requirements in the current environment, thereby enabling the image acquisition module 110 to acquire a clear image that meets the brightness requirements.

[0048] In some examples, the image acquisition module 110 may include an infrared camera; the light source 132 may include an infrared light source; the target image may be a target image (for example, an image including the target under an infrared light source and acquired by an infrared camera under an infrared light source); the current brightness of the target image obtained by processing the target image by the control module 120 may be the brightness of the infrared light, and then through the above-mentioned light source dimming system, real-time adjustment of the light intensity of the infrared light source may be achieved to realize targeted fill light of the infrared light source, thereby avoiding the infrared camera being unable to acquire a clear target image due to insufficient brightness of the infrared light source. This can be applied to AR devices to realize precise navigation and positioning of AR devices under appropriate light intensity.

[0049] The light source dimming system provided in the embodiment of the present application includes: an image acquisition module, the image acquisition module is used to acquire a target image, and the target image can be used to reflect the ambient brightness under the current light source conditions; a control module, the control module is connected to the image acquisition module, the control module processes the target image, obtains the current brightness of the target image, and outputs a control signal based on the current brightness of the target image; a dimming circuit, the dimming circuit is connected to the control module; the dimming circuit includes a light source; the dimming circuit controls the average current of the light source based on the control signal to adjust the light intensity of the light source. The light source dimming system can realize real-time adjustment of the light intensity of the light source, which can be used not only for brightness adjustment of visible light sources, but also for brightness adjustment of invisible light sources, thereby improving the fill light effect of the light source to meet the light intensity requirements in the current environment, so that the image acquisition module can acquire a clear image that meets the brightness requirements.

[0050] In one embodiment, if Figure 2 As shown, the dimming circuit 130 further includes:

[0051] A driving module 210, the driving module 210 includes a sampling element 212 and a switch element 214; the input end of the driving module 210 is used to connect to a power source; the output end of the driving module 210 is connected to the light source 132;

[0052] A sampling module 220, the sampling module 220 is connected to the sampling element 212; the sampling module 220 samples the current flowing through the sampling element 212 and outputs a sampling signal;

[0053] The control module 120 is connected to the sampling module 220 and the control end of the switch element 214 ; the control module 120 receives the sampling signal and outputs a control signal based on the sampling signal for adjusting the PWM frequency and / or duty cycle of the switch element 214 .

[0054] Specifically, the input end of the driving module 210 is used to connect to the power supply. When the power supply is connected, the driving module 210 can be started to allow current to flow between the sampling element 212 and the light source 132. The sampling element 212 in the driving module 210 can be connected through the sampling module 220 to obtain the current flowing through the sampling element 212, and the current flowing through the sampling element 212 can be used to reflect the average current of the light source 132. Further, the sampling module 220 can sample the current flowing through the sampling element 212, obtain a sampling signal and output it. The control module 120 can receive the sampling signal by connecting to the sampling module 220, and process the sampling signal accordingly, for example, obtain the current average value corresponding to the sampling signal, so as to output a corresponding control signal based on the sampling signal. The control module 120 can output the control signal to the control end of the switching element 214 by connecting to the control end of the switching element 214, wherein the control signal can be obtained based on the current brightness of the target image, and the PWM frequency and / or duty cycle of the switching element 214 can be adjusted through the control signal, thereby adjusting the average current of the light source 132, thereby achieving real-time adjustment of the light intensity of the light source.

[0055] In one of the embodiments, the control module 120 outputs a control signal for increasing the PWM frequency and / or duty cycle of the switch element 214 when the current brightness of the target image is less than or equal to a preset value;

[0056] When the current brightness of the target image is greater than a preset value, the control module 120 outputs a control signal for reducing the PWM frequency and / or the duty cycle of the switch element 214 .

[0057] Specifically, the control module 120 may compare the current brightness of the target image obtained with the preset value. When the current brightness of the target image is less than or equal to the preset value, the control module 120 may output a corresponding control signal to increase the PWM frequency and / or duty cycle of the switch element 214, thereby increasing the average current of the light source 132 and thereby improving the brightness of the light source 132. When the current brightness of the target image is greater than the preset value, the control module 120 may output a corresponding control signal to reduce the PWM frequency and / or duty cycle of the switch element 214, thereby reducing the average current of the light source 132 and thereby reducing the brightness of the light source 132. By adjusting the PWM frequency and / or duty cycle of the switch element 214 in the above manner, the light intensity of the light source 132 may be adjusted in real time to meet the light intensity requirement in the current environment, thereby enabling the image acquisition module to acquire a clear image that meets the brightness requirement.

[0058] In one embodiment, if Figure 3 As shown, the control module 120 includes:

[0059] A comparison unit 310, the comparison unit 310 is connected to the sampling module 220; the comparison unit 310 receives the sampling signal, and outputs a comparison signal based on a preset threshold and the sampling signal;

[0060] The operation circuit 320 is connected to the comparison unit 310 and the control end of the switch element 214; the operation circuit 320 receives the comparison signal and outputs a control signal based on the PWM signal and the comparison signal; the PWM signal is the current brightness setting of the control module 120 based on the target image.

[0061] Specifically, the comparison unit 310 can be connected to the sampling module 220 to receive the sampling signal, and output a comparison signal based on a preset threshold and the sampling signal. For example, when the sampling signal is less than or equal to the preset threshold, the comparison unit 310 can output a high-level (or low-level) comparison signal, and when the sampling signal is greater than the preset threshold, the comparison unit 310 can output a low-level (or high-level) comparison signal; the operation circuit 320 can be connected to the comparison unit 310 to receive the comparison signal output by the comparison unit 310, and the operation circuit 320 can output a control signal based on the PWM signal and the comparison signal, wherein the PWM signal The control module 120 may be set based on the current brightness of the target image. The control module 120 may set the PWM frequency and / or duty cycle of the PWM signal based on the current brightness of the target image. If the comparison signal is at a high level, the operation circuit 320 may output a high-level control signal based on the PWM signal and the comparison signal, and the switch element 214 may increase the current current of the light source 132 based on the high-level control signal. If the comparison signal is at a low level, the operation circuit 320 may output a low-level control signal based on the PWM signal and the comparison signal, and the switch element 214 may reduce the current current of the light source 132 based on the low-level control signal. The average current of the light source 132 is determined by the PWM signal set by the control module 120 based on the current brightness of the target image. For example, the average current of the light source 132 may be increased by increasing the PWM frequency and / or duty cycle of the PWM signal, and the average current of the light source 132 may be reduced by reducing the PWM frequency and / or duty cycle of the PWM signal.

[0062] In one embodiment, if Figure 4 As shown, the input end of the switch element 214 is used to access the power supply; the driving module 210 also includes:

[0063] An inductor L1, one end of the inductor L1 is connected to the output end of the switch element 214;

[0064] A unidirectional conductive element, wherein the current output end of the unidirectional conductive element is connected to the output end of the switch element 214; the current input end of the unidirectional conductive element is also used for grounding;

[0065] Capacitor C1, one end of the capacitor C1 is connected to the other end of the inductor L1; the other end of the capacitor C1 is connected to one end of the sampling element 212; the other end of the sampling element 212 is connected to the current input end of the unidirectional conductive element.

[0066] Specifically, the input end of the switch element 214 can be connected to a power supply, for example, a 24V DC power supply; the output end of the switch element 214 can be connected to one end of the inductor L1, and the inductor L1 can be used for energy storage and voltage reduction; the unidirectional conductive element can include a diode D1, the current output end of the unidirectional conductive element is connected to the output end of the switch element 214, and the current input end of the unidirectional conductive element can be grounded (GND); one end of the capacitor C1 is connected to the other end of the inductor L1, and the other end of the capacitor C1 is connected to one end of the sampling element 212, and the other end of the sampling element 212 is connected to the current input end of the unidirectional conductive element, wherein the capacitor C1 can be used for voltage stabilization, and the sampling element 212 can include a sampling resistor R1. When the switch element 214 is turned on, the unidirectional conductive element is not turned on, no current flows through the unidirectional conductive element, and the inductor L1 stores energy under the action of the inductor L1 current; when the switch element 214 is turned off, since the inductor L1 current in the inductor L1 cannot change suddenly, the unidirectional conductive element provides a freewheeling circuit. The capacitor C1 can be connected in parallel with the light source 132. For example, one end of the capacitor C1 can be connected to the current input end of the light source 132, and the other end of the capacitor C1 can be connected to the current output end of the light source 132. The light source 132 can include a light emitting diode D2, such as an infrared light emitting diode. The driving module 210 can provide a driving current for the light emitting diode D2, and the sampling resistor R1 can perform current sampling on the loop in the driving module 210 to reflect the average current in the light source 132.

[0067] In some examples, the switch element 214 may include a MOS tube (Metal Oxide Semiconductor Field Effect Transistor, MOSFET, metal oxide semiconductor field effect transistor) Q1; the light source 132 may include 8 PCS specification infrared light emitting diodes connected in series.

[0068] In one embodiment, if Figure 4 As shown, the comparison unit 310 includes:

[0069] Comparator U2, one input end of comparator U2 is used to access a voltage source with a preset threshold; the other input end of comparator U2 is connected to sampling module 220 to receive a sampling signal; the output end of comparator U2 outputs a comparison signal obtained by comparing the preset threshold and the sampling signal.

[0070] Specifically, one input end of the comparator U2 can be connected to a voltage source with a preset threshold value, for example, an external voltage source can provide a preset threshold value Vref=0.2V, and the other input end of the comparator U2 can be connected to the sampling module 220 to receive a sampling signal, for example, the sampling signal can be the voltage value across the sampling element 212, taking the sampling resistor R1 as an example, the transient voltage value VR1 across the sampling resistor R1 is proportional to the transient current flowing through the sampling resistor R1, and is also proportional to the inductor current flowing through the inductor L1, and the sampling module 220 can collect the voltage value VR1 in real time, and the voltage value VR1 can be used to reflect the average current flowing through the light source 132. The comparator U2 can output a corresponding comparison signal based on the preset threshold value Vref and the sampling signal, for example, when the sampling signal is less than or equal to the preset threshold value Vref, the comparator U2 can output a high-level comparison signal, and when the sampling signal is greater than the preset threshold value Vref, the comparator U2 can output a low-level comparison signal. Through the above-mentioned comparator U2, the size of the sampling signal can be judged, and a reference is provided for the operation circuit 320 to output a control signal.

[0071] In some examples, the sampling module 220 may include a voltage sampling chip. The comparator U2 may be powered by a single power supply or a dual power supply. For example, the comparator U2 may be powered by a 5V single power supply. The input terminal Vi+ of the comparator U2 may be connected to a voltage source of a preset threshold value Vref, and the input terminal Vi- of the comparator U2 may be connected to the sampling module 220; the output terminal Vout of the comparator U2 may be connected to the operation circuit 320.

[0072] In one embodiment, there is a delay time between the input terminal of the comparator U2 and the output terminal of the comparator U2.

[0073] Specifically, the comparator U2 may have an output protection function, and there is a delay time Tp between the input end of the comparator U2 and the output end of the comparator U2. Before the delay time Tp, if there is no valid input at the input end of the comparator U2, the output end of the comparator U2 may maintain a low level output; before the delay time Tp, if there is a valid input at the input end of the comparator U2, the comparison signal output by the output end of the comparator U2 is determined based on the input signal at the input end of the comparator U2 before the delay time Tp. By setting the above delay time, the stability of the driving light source can be improved.

[0074] In one embodiment, if Figure 4 As shown, the operation circuit 320 includes:

[0075] The AND gate circuit U1 has one input terminal connected to the comparison unit 310 to receive the comparison signal; another input terminal of the AND gate circuit U1 receives the PWM signal; and the output terminal of the AND gate circuit U1 is connected to the control terminal of the switch element 214 to output the control signal.

[0076] Specifically, the AND gate circuit U1 outputs a control signal to the control end of the switch element 214 based on the comparison signal output by the comparison unit 310 and the connected PWM signal. When the comparison signal and the PWM signal input to the AND gate circuit U1 are both high level (logic 1), the output of the AND gate circuit U1 is high level, that is, the control signal output to the control end of the switch element 214 is high level, and the switch element 214 is turned on based on the high level control signal; when at least one of the comparison signal and the PWM signal input to the AND gate circuit U1 is low level (logic 0), the output of the AND gate circuit U1 is low level, that is, the control signal output to the control end of the switch element 214 is low level, and the switch element 214 is turned off based on the low level control signal. Among them, the AND gate circuit U1 can be an AND gate circuit with a delay function. By setting the above-mentioned AND gate circuit, a control signal can be output based on the comparison signal obtained by the sampling signal to control the switch element, and the loop current in the driving module can be adjusted in real time, thereby adjusting the average current output to the light source.

[0077] In some examples, one input end of the AND gate circuit U1 can be connected to the output end of the comparator U2; when the comparison signal output at the output end of the comparator U2 is low level, or the PWM signal input to the input end of the AND gate circuit U1 is low level, the output end of the AND gate circuit U1 outputs a low level, the MOS tube Q1 in the driving module 210 is turned off, and the inductor current in the driving module 210 is reduced; when the comparison signal output at the output end of the comparator U2 is low level, and the PWM signal input to the input end of the AND gate circuit U1 is low level, the output end of the AND gate circuit U1 outputs a low level, the MOS tube Q1 in the driving module 210 is turned off, and the inductor current in the driving module 210 is reduced; when the comparison signal output at the output end of the comparator U2 is high level, and the PWM signal input to the input end of the AND gate circuit U1 is high level, the output end of the AND gate circuit U1 outputs a high level, the MOS tube Q1 in the driving module 210 is closed, and the inductor current in the driving module 210 is increased. The inductor current in the driving module 210 is filtered by the capacitor C1 and then output as the average current in the light source 132 .

[0078] In some examples, such as Figure 5As shown, when the LED lamp beads of the light source emit light, the target image can be obtained and output by taking pictures with a camera, and the image brightness can be further obtained based on the target image, and the image brightness is input to the main control chip. The main control chip can obtain the image brightness of the target image and output the corresponding PWM signal to the AND gate circuit. The sampling circuit samples the current in the drive circuit and inputs the sampling signal to the comparator. The comparator compares the input sampling signal with the preset threshold value and outputs the comparison signal to the AND gate circuit. The AND gate circuit outputs the MOSFET drive signal to the drive circuit based on the input PWM signal and the comparison signal to adjust the current in the drive circuit. The drive circuit outputs the current to the LED lamp beads, thereby realizing the adjustment of the average current output to the LED lamp beads, and the luminous intensity of the LED lamp beads can change with the change of the average current of the LED lamp beads.

[0079] In some examples, such as Figure 6 As shown, after initialization, the image can be output to the main control chip by taking a photo. The main control chip processes the image to obtain the brightness of the image and determines the brightness of the image. If the brightness of the image is determined to be low, the PWM frequency or duty cycle of the PWM signal output to the AND gate circuit can be increased, so that the LED current increases and the LED light intensity increases, so as to re-acquire the image with increased brightness; if the brightness of the image is determined to be high, the PWM frequency or duty cycle of the PWM signal output to the AND gate circuit can be reduced, so that the LED current decreases and the LED light intensity decreases, so as to re-acquire the image with reduced brightness; if the brightness of the image is determined to be normal, the photo can be continued to be taken to obtain an image that meets the brightness requirements in real time, so as to meet the accuracy requirements of the camera navigation and positioning function.

[0080] In some examples, the current protection threshold Ip can be set based on the preset threshold Vref and the resistance value of the sampling resistor R1, where the current protection threshold Ip=Vref / R1; the average current of the light source 132 can be adjusted in the following manner:

[0081] When the high level duty cycle of the PWM signal is 100% and the maximum PWM frequency is 400kHz (the PWM frequency range can be set to 200kHz-400kHz), the average current output to the light source 132 is as follows: Figure 7aAs shown. When the inductor current is less than or equal to the current protection threshold Ip, the preset threshold Vref of the input comparator U2 is greater than the voltage value VR1 of the sampling resistor R1, the comparison signal output by the comparator U2 is high level, and after the comparison signal and the PWM signal pass through the AND gate circuit U1, the output control signal is still high level. Under the action of the control signal on the MOS tube Q1, the inductor current increases. When the inductor current is greater than the current protection threshold Ip, the preset threshold Vref of the input comparator U2 is less than the voltage value VR1 of the sampling resistor R1, the comparison signal output by the comparator U2 is low level, and after the comparison signal and the PWM signal pass through the AND gate circuit U1, the output control signal is low level. Under the action of the control signal on the MOS tube Q1, the inductor current decreases. After the delay time Tp, the inductor current decreases from the current protection threshold Ip to Im1, the comparator U2 outputs a high level comparison signal again, and the AND gate circuit U1 outputs a high level control signal. In the above manner, the average current output to the light source 132 is Id1.

[0082] When the high-level duty cycle of the PWM signal is 75% and the PWM frequency is the maximum value of 400kHz (the PWM frequency range is set to 200kHz-400kHz), the average current output to the light source 132 is as follows: Figure 7b As shown. When the inductor current is less than or equal to the current protection threshold Ip, the preset threshold Vref of the input comparator U2 is greater than the voltage value VR1 of the sampling resistor R1, and the comparison signal output by the comparator U2 is high level. After the comparison signal and the PWM signal pass through the AND gate circuit U1, the output control signal is still high level. Under the action of the control signal on the MOS tube Q1, the inductor current increases. When the inductor current is greater than the current protection threshold Ip, the preset threshold Vref of the input comparator U2 is less than the voltage value VR1 of the sampling resistor R1, and the comparison signal output by the comparator U2 is low level. After the comparison signal and the PWM signal pass through the AND gate circuit U1, the output control signal is low level. Under the action of the control signal on the MOS tube Q1, the inductor current decreases. After the delay time Tp, the preset threshold value Vref of the input comparator U2 is greater than the voltage value VR1 of the sampling resistor R1, and the comparison signal output by the comparator U2 is high level. Since the PWM signal is low level at this time, the output is low level after passing through the AND gate circuit U1. Under the action of the control signal on the MOS tube Q1, the inductor current continues to decrease. When the inductor current continues to decrease to Im2, when the PWM signal is reset to a high level, the comparator U2 re-outputs a high level comparison signal, and the AND gate circuit U1 outputs a high level control signal. In the above manner, the average current output to the light source 132 is Id2.

[0083] When the high-level duty cycle of the PWM signal is 75% and the PWM frequency is the maximum value of 200kHz (the PWM frequency range is set to 200kHz-400kHz), the average current output to the light source 132 is as follows: Figure 7c As shown. When the inductor current is less than or equal to the current protection threshold Ip, the preset threshold Vref of the input comparator U2 is greater than the voltage value VR1 of the sampling resistor R1, and the comparison signal output by the comparator U2 is high level. After the comparison signal and the PWM signal pass through the AND gate circuit U1, the output control signal is still high level. Under the action of the control signal on the MOS tube Q1, the inductor current increases. When the inductor current is greater than the current protection threshold Ip, the preset threshold Vref of the input comparator U2 is less than the voltage value VR1 of the sampling resistor R1, and the comparison signal output by the comparator U2 is low level. After the comparison signal and the PWM signal pass through the AND gate circuit U1, the output control signal is low level. Under the action of the control signal on the MOS tube Q1, the inductor current decreases. After the delay time Tp, the preset threshold Vref of the input comparator U2 is greater than the voltage value VR1 of the sampling resistor R1, and the comparison signal output by the comparator U2 is high level. Since the PWM signal is still high level, the control signal output by the AND gate circuit U1 is high level. Under the action of the control signal on the MOS tube Q1, the inductor current begins to increase. After time t1, the inductor current is less than or equal to the current protection threshold Ip, the comparator U2 outputs a high level, the PWM signal changes from a high level to a low level, and the control signal output by the AND gate circuit U1 is a low level. Under the action of the control signal on the MOS tube Q1, the inductor current begins to decrease. When the inductor current continues to decrease to Im3, when Im3 = 0, the inductor current no longer decreases. When the PWM signal is set high again, the above-mentioned comparator U2 outputs a high-level comparison signal, and the AND gate circuit U1 outputs a high-level control signal. In the above manner, the average current output to the light source 132 is Id3.

[0084] By comparing the average currents output to the light source 132 in the above three modes, it can be obtained that Id3<Id2<Id1. That is, when reducing the duty cycle of the PWM signal and / or lowering the PWM frequency, the average current output to the light source 132 can be effectively reduced, and increasing the duty cycle of the PWM signal and / or lowering the PWM frequency can increase the average current output to the light source 132.

[0085] In one embodiment, a control module is provided, whose internal structure diagram can be as follows: Figure 8As shown. The control module includes a processor, a memory, an input / output interface, a communication interface and an input device. Among them, the processor, the memory and the input / output interface are connected through a system bus, and the communication interface and the input device are connected to the system bus through the input / output interface. Among them, the processor of the control module is used to provide computing and control capabilities. The memory of the control module includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the control module is used to exchange information between the processor and an external device. The communication interface of the control module is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a light source dimming method is implemented.

[0086] Those skilled in the art will understand that Figure 8 The structure shown in the figure is only a block diagram of a partial structure related to the scheme of the present application, and does not constitute a limitation on the control module to which the scheme of the present application is applied. The specific control module may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0087] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0088] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0089] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A light source dimming system, characterized in that: The system comprises: An image acquisition module, wherein the image acquisition module is used to acquire a target image; A control module, wherein the control module is connected to the image acquisition module, and the control module processes the target image to obtain the current brightness of the target image, and outputs a control signal based on the current brightness of the target image; A dimming circuit is connected to the control module; the dimming circuit includes a light source; the dimming circuit controls an average current of the light source based on the control signal to adjust the light intensity of the light source.

2. The system according to claim 1, characterized in that The dimming circuit also includes: A driving module, the driving module comprising a sampling element and a switch element; the input end of the driving module is used to connect to a power source; the output end of the driving module is connected to the light source; A sampling module, the sampling module is connected to the sampling element; the sampling module samples the current flowing through the sampling element and outputs a sampling signal; The control module is connected to the sampling module and the control end of the switch element; the control module receives the sampling signal and outputs the control signal based on the sampling signal to adjust the PWM frequency and / or duty cycle of the switch element.

3. The system according to claim 1, characterized in that The control module outputs the control signal for increasing the PWM frequency and / or duty cycle of the switching element when the current brightness of the target image is less than or equal to a preset value; The control module outputs the control signal for reducing the PWM frequency and / or the duty cycle of the switching element when the current brightness of the target image is greater than a preset value.

4. The system according to claim 2, characterized in that The control module comprises: A comparison unit, the comparison unit is connected to the sampling module; the comparison unit receives the sampling signal and outputs a comparison signal based on a preset threshold and the sampling signal; An operation circuit is connected to the comparison unit and the control end of the switch element; the operation circuit receives the comparison signal and outputs the control signal based on the PWM signal and the comparison signal; the PWM signal is set by the control module based on the current brightness of the target image.

5. The system according to claim 2, characterized in that The input end of the switch element is used to connect to the power supply; the driving module also includes: an inductor, one end of which is connected to the output end of the switch element; A unidirectional conductive element, wherein the current output end of the unidirectional conductive element is connected to the output end of the switch element; and the current input end of the unidirectional conductive element is also used for grounding; A capacitor, one end of which is connected to the other end of the inductor; the other end of the capacitor is connected to one end of the sampling element; and the other end of the sampling element is connected to the current input end of the unidirectional conductive element.

6. The system according to claim 4, characterized in that The comparison unit comprises: A comparator, wherein one input end of the comparator is used to access the voltage source of the preset threshold; another input end of the comparator is connected to the sampling module to receive the sampling signal; and the output end of the comparator outputs the comparison signal obtained by comparing the preset threshold and the sampling signal.

7. The system according to claim 4, characterized in that The operation circuit comprises: An AND gate circuit, one input end of the AND gate circuit is connected to the comparison unit to receive the comparison signal; the other input end of the AND gate circuit is connected to the PWM signal; the output end of the AND gate circuit is connected to the control end of the switch element to output the control signal.

8. The system according to claim 1, characterized in that The image acquisition module includes an infrared camera; the light source includes an infrared light emitting diode.

9. The system according to claim 1, characterized in that The sampling element includes a sampling resistor.

10. The system according to claim 6, characterized in that There is a delay time between the input terminal of the comparator and the output terminal of the comparator.

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