Current signal compensation method and device

Abstract

An embodiment of the present invention provides a current signal compensation method and apparatus, comprising: obtaining a first compensation current signal corresponding to the current state of a first analog camera; using the first compensation current signal to compensate a first load current signal of the first analog camera to obtain a first target current signal; and transmitting the first target current signal to the negative terminal of a first power input port, the first target current signal being used to maintain a constant first component current signal. This invention solves the problem, existing in the related art, that when powering analog cameras centrally, fluctuations in the load current of the analog camera can affect the image quality of other analog cameras.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of analog cameras, and in particular, to a current signal compensation method and device. Background Art

[0002] In analog camera applications, to reduce the difficulty and cost of engineering wiring, a single power supply is used to centrally power analog cameras at various locations, and these cameras are connected to the same digital video recorder (DVR). When using a single power supply to power multiple analog cameras, the load current of each camera is split into two parts and returns to the negative terminal of the power supply. One part of this current flows through the DVR and other analog cameras and then back to the negative terminal of the power supply. During the blanking period of the video signal, the load current of the analog camera fluctuates, causing the current flowing through the DVR and other analog cameras to also fluctuate. This current fluctuation can interfere with the normal image display of other analog cameras, resulting in horizontal streaks in the displayed image. Therefore, the existing technology for centralized power supply of analog cameras suffers from the problem that the fluctuation of the load current of the analog camera affects the image quality of other analog cameras.

[0003] With respect to the problem in the related art that when powering analog cameras centrally, fluctuations in the load current of the analog cameras affect the image quality of other analog cameras, no effective solution has been proposed so far. Summary of the Invention

[0004] The embodiments of the present invention provide a current signal compensation method and device to at least solve the problem in the related art that when power is supplied to analog cameras in a centralized manner, the fluctuation of the load current of the analog cameras affects the image quality of other analog cameras.

[0005] According to one embodiment of the present invention, a current signal compensation method is provided, comprising: obtaining a first compensation current signal corresponding to a current state of a first analog camera, wherein a first power input port of the first analog camera is connected to a target power supply, a second power input port of a second analog camera is connected to the target power supply, a first video output port of the first analog camera is connected to a first channel input port of a digital video recorder, and a second video output port of the second analog camera is connected to a second channel input port of the digital video recorder;

[0006] Compensating a first load current signal of the first analog camera using the first compensation current signal to obtain a first target current signal;

[0007] The first target current signal is transmitted to the negative pole of the first power input port, wherein the first component current signal of the first target current signal flows through the negative pole of the first video output port, the negative pole of the first channel input port, the negative pole of the second channel input port, the negative pole of the second video output port, and the negative pole of the second power input port, and returns to the negative pole of the target power supply, and the first target current signal is used to keep the first component current signal constant.

[0008] In an exemplary embodiment, obtaining a first compensation current signal corresponding to a current state of a first analog camera includes: obtaining the current state of the first analog camera; when the current state of the first analog camera is the first state, determining a first initial compensation voltage signal corresponding to the first state of the first analog camera according to a preset set of correspondences, wherein each correspondence in the set of correspondences is a correspondence between a state of the first analog camera and an initial compensation voltage signal determined under the state, and the first initial compensation voltage signal is an initial compensation voltage signal determined based on a load current signal of the first analog camera when the camera is in the first state; and performing signal processing on the initial compensation voltage signal to obtain the first compensation current signal.

[0009] In an exemplary embodiment, signal processing is performed on the initial compensation voltage signal to obtain the first compensation current signal, including: performing gain correction on the initial compensation voltage signal according to the current power supply voltage of the first analog camera to obtain a target correction signal, wherein the current power supply voltage is the power supply voltage provided by the target power supply to the first analog camera through the first power input port; converting the target correction signal into a target compensation voltage signal through a digital-to-analog converter in the first analog camera; and converting the target compensation voltage signal into the first compensation current signal through a voltage-controlled current source unit in the first analog camera.

[0010] In an exemplary embodiment, the initial compensation voltage signal is gain corrected according to the current power supply voltage of the first analog camera to obtain a target correction signal, including: obtaining the current power supply voltage and a preset power supply voltage of the first analog camera, wherein the preset power supply voltage is the power supply voltage provided to the first analog camera when determining the first initial compensation voltage signal; determining the ratio of the preset power supply voltage to the current power supply voltage as a target coefficient; and scaling the initial compensation voltage signal by the target coefficient to obtain the target correction signal.

[0011] In an exemplary embodiment, the target correction signal is converted into a target compensation voltage signal by a digital-to-analog converter in the first analog camera, including: obtaining a preset maximum output voltage and a preset accuracy parameter of the digital-to-analog converter; and performing digital-to-analog conversion on the target correction signal according to the preset maximum output voltage and the preset accuracy parameter to obtain the target compensation voltage signal.

[0012] In an exemplary embodiment, converting the target compensation voltage signal into the first compensation current signal by a voltage-controlled current source unit in the first analog camera includes: obtaining a feedback resistance and a voltage drop of the voltage-controlled current source unit; and converting the target compensation voltage signal into the first compensation current signal according to the feedback resistance and the voltage drop.

[0013] In an exemplary embodiment, the above method also includes: obtaining a load current signal of the first analog camera when it is in the first state; obtaining a maximum load current and a minimum load current in the load current signal of the first analog camera when it is in the first state; obtaining preset accuracy parameters of the digital-to-analog converter in the first analog camera and a feedback resistance and a voltage drop of a voltage-controlled current source unit in the first analog camera; determining the first initial compensation voltage signal corresponding to the first state based on the preset accuracy parameters, the feedback resistance, the voltage drop, the maximum load current and the minimum load current, and establishing a corresponding relationship between the first state and the first initial compensation voltage signal.

[0014] In an exemplary embodiment, the above method also includes: obtaining a second compensation current signal corresponding to the current state of the second analog camera; using the second compensation current signal to compensate the second load current signal of the second analog camera to obtain a second target current signal; transmitting the second target current signal to the negative pole of the second power input port, wherein the second component current signal of the second target current signal flows through the negative pole of the second video output port, the negative pole of the second channel input port, the negative pole of the first channel input port, the negative pole of the first video output port, and the negative pole of the first power input port, and returns to the negative pole of the target power supply, and the second target current signal is used to keep the second component current signal constant.

[0015] According to yet another embodiment of the present invention, a current signal compensation device is provided, comprising: a first acquisition unit, configured to acquire a first compensation current signal corresponding to a current state of a first analog camera, wherein a first power input port of the first analog camera is connected to a target power supply, a second power input port of a second analog camera is connected to the target power supply, a first video output port of the first analog camera is connected to a first channel input port of a digital video recorder, and a second video output port of the second analog camera is connected to a second channel input port of the digital video recorder;

[0016] a compensation unit, configured to compensate a first load current signal of the first analog camera using the first compensation current signal to obtain a first target current signal;

[0017] A transmission unit transmits the first target current signal to the negative pole of the first power input port, wherein the first component current signal of the first target current signal flows through the negative pole of the first video output port, the negative pole of the first channel input port, the negative pole of the second channel input port, the negative pole of the second video output port, and the negative pole of the second power input port, and returns to the negative pole of the target power supply, and the first target current signal is used to keep the first component current signal constant.

[0018] According to yet another embodiment of the present invention, a computer-readable storage medium is provided, in which a computer program is stored. The computer program is configured to execute the steps of any one of the above method embodiments when run.

[0019] According to another embodiment of the present invention, an electronic device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor is configured to run the computer program to perform the steps in any one of the above method embodiments.

[0020] In an embodiment of the present invention, the first load current signal of the first camera is compensated by the first compensation current signal. The first target current signal obtained after compensation is constant. Therefore, the first component signal of the first target current signal also remains constant and does not fluctuate in the frame blanking area of the video signal. Therefore, it does not interfere with the normal image display of other analog cameras, that is, no horizontal stripes will appear when the image is displayed, thereby solving the problem in the related art that the fluctuation of the load current of the analog camera affects the image quality of other analog cameras when the analog cameras are centrally powered, and achieving the effect of avoiding the appearance of horizontal stripes in the images taken by each analog camera when the analog cameras are centrally powered. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1This is a block diagram of the hardware structure of a mobile terminal according to the current signal compensation method of an embodiment of the present invention;

[0022] Figure 2 is a flow chart of a current signal compensation method according to an embodiment of the present invention;

[0023] Figure 3 is a topological diagram of centralized power supply for analog cameras according to an embodiment of the present invention;

[0024] Figure 4 This is a schematic diagram of the current interference of a simulated camera according to an embodiment of the present invention. Figure 1 ;

[0025] Figure 5 This is a schematic diagram of the current interference of a simulated camera according to an embodiment of the present invention. Figure 2 ;

[0026] Figure 6 is a schematic diagram of the phase relationship between the analog camera video signal and the analog camera power consumption current according to an embodiment of the present invention;

[0027] Figure 7 is a schematic diagram of video signal interference when a centralized power supply is applied to an analog camera according to an embodiment of the present invention;

[0028] Figure 8 is a schematic structural diagram of an optional voltage-controlled current source unit according to an embodiment of the present invention;

[0029] Figure 9 is a schematic structural diagram of a compensation system for analog camera current signals according to an embodiment of the present invention;

[0030] Figure 10 is an overall flow chart of a current signal compensation method according to an embodiment of the present invention;

[0031] Figure 11 is a timing diagram of current signal compensation according to an embodiment of the present invention;

[0032] Figure 12 4 is a structural block diagram of a current signal compensation device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0033] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings and in combination with embodiments.

[0034] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0035] The method embodiments provided in the embodiments of the present application can be executed in a mobile terminal, a computer terminal or a similar computing device. Taking running on a mobile terminal as an example, Figure 1 FIG. 1 is a block diagram of the hardware structure of a mobile terminal according to an embodiment of the present invention, which is a method for compensating a current signal. Figure 1 As shown, the mobile terminal may include one or more ( Figure 1 Only one is shown) a processor 102 (the processor 102 may include but is not limited to a microprocessor MCU or a programmable logic device FPGA and other processing devices) and a memory 104 for storing data, wherein the mobile terminal may also include a transmission device 106 and an input and output device 108 for communication functions. It will be understood by those skilled in the art that Figure 1 The structure shown is only for illustration and does not limit the structure of the mobile terminal. Figure 1 More or fewer components than shown, or with Figure 1 Different configurations shown.

[0036] The memory 104 can be used to store computer programs, such as software programs and modules of application software, such as the computer program corresponding to the current signal compensation method in the embodiment of the present invention. The processor 102 executes the computer program stored in the memory 104 to perform various functional applications and data processing, thereby implementing the above-mentioned method. The memory 104 may include high-speed random access memory and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some examples, the memory 104 may further include memory remotely located relative to the processor 102, and these remote memories may be connected to the mobile terminal via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0037] The transmission device 106 is used to receive or send data via a network. A specific example of the aforementioned network may include a wireless network provided by the mobile terminal's communications provider. In one embodiment, the transmission device 106 includes a network interface controller (NIC), which can be connected to other network devices via a base station to enable communication with the Internet. In one embodiment, the transmission device 106 may be a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0038] In this embodiment, a current signal compensation method is provided. Figure 2 FIG. 1 is a flow chart of a current signal compensation method according to an embodiment of the present invention. Figure 2As shown, the process includes the following steps:

[0039] Step S202: Acquire a first compensation current signal corresponding to a current state of a first analog camera, wherein a first power input port of the first analog camera is connected to a target power supply, a second power input port of a second analog camera is connected to the target power supply, a first video output port of the first analog camera is connected to a first channel input port of a digital video recorder, and a second video output port of the second analog camera is connected to a second channel input port of the digital video recorder;

[0040] Step S204, using the first compensation current signal to compensate the first load current signal of the first analog camera to obtain a first target current signal;

[0041] Step S206, transmitting the first target current signal to the negative pole of the first power input port, wherein the first component current signal of the first target current signal flows through the negative pole of the first video output port, the negative pole of the first channel input port, the negative pole of the second channel input port, the negative pole of the second video output port, and the negative pole of the second power input port, and returns to the negative pole of the target power supply, and the first target current signal is used to keep the first component current signal constant.

[0042] In this embodiment, the first analog camera and the second analog camera are powered by the same power supply (i.e., the target power supply), and both the first analog camera and the second analog camera are connected to the same digital video recorder (DVR). Each analog camera has a power input port and a video output port. The power supply is connected to the power input port of the analog camera to provide power to the analog camera, and the video output port of the analog camera is connected to the channel input port of the DVR to transmit the analog video signal captured by the analog camera to the DVR, which converts the analog video signal into a digital signal and stores it. It should be noted that the DVR has multiple channel input ports, and different analog cameras are connected to different channel input ports.

[0043] Figure 3 : is a topological diagram of centralized power supply for analog cameras according to an embodiment of the present invention, such as Figure 3 As shown, the first analog camera is connected to the first power input port (corresponding to Figure 3 "P1+", "P1-") in the target power supply, the first video output port of the first analog camera (corresponding to Figure 3 "V1+", "V1-") and the first channel input port of the digital video recorder (corresponding to Figure 3"CH1+", "CH1-") connection in the

[0044] The second analog camera is connected to the second power input port (corresponding to Figure 3 "P2+", "P2-") in the target power supply, the second video output port of the second analog camera (corresponding to Figure 3 "V2+", "V2-") and the second channel input port of the digital video recorder (corresponding to Figure 3 "CH2+", "CH2-") connection;

[0045] Inside the camera, the power input and video output share a common ground, that is, "P1-" and "V1-" are connected inside the first analog camera, "P1-" and "V1-" are connected inside the second analog camera, and all channels of the digital video recorder DVR also share a common ground, that is, "CH1-" and "CH2-" are connected inside the DVR. Figure 3 In the figure, dotted lines connect "P1-" and "V1-", "P1-" and "V1-", "CH1-" and "CH2-", and R-1 and R-2 are the terminal sampling resistors of the DVR channel.

[0046] Figure 4 This is a schematic diagram of the current interference of a simulated camera according to an embodiment of the present invention. Figure 1 ,like Figure 4 As shown, when only one analog camera is connected to the power supply, the power supply current of the first analog camera should return directly to the negative pole of the target power supply from abfe. Due to the centralized power supply, multiple analog cameras are connected to the target power supply, which constructs other return paths. The power supply current of the first analog camera will not only return to the negative pole of the target power supply through the abfe path, but also to the negative pole of the target power supply through I p1 , and part of the current will return to the negative pole of the target power supply through the abfghnmqe path, that is, I b1 (i.e. the first component current signal mentioned above). Similarly, Figure 5 This is a schematic diagram of the current interference of a simulated camera according to an embodiment of the present invention. Figure 2 ,like Figure 5 As shown, the current of the second analog camera not only returns to the negative pole of the target power supply through the APQE path, that is, I p2 , and part of the current will return to the negative pole of the target power supply through the apqmnhgfe path, that is, I b2 .

[0047] Analog cameras are usually placed at monitoring points, and digital video recorders are usually placed in monitoring rooms. Therefore, the distance between analog cameras and digital video recorders is usually far, and the connecting cables are long, so the corresponding impedance will also be large and cannot be ignored. Figure 4 and Figure 5 In the figure, Rgh and Rmn represent the impedance of the coaxial video line (-) end of the gh segment and the mn segment respectively, that is, the impedance between the negative electrode of the video output port and the negative electrode of the channel input port. Figure 4 and Figure 5 I in v1 , I v2 The video source outputs of the first analog camera and the second analog camera flow through the DVR terminal sampling resistor and return to the current path of the analog camera.

[0048] The video valid lines are the lines with video image modulation signals. In the time domain, the video valid lines are called the video valid area. The areas other than the video valid area are all frame blanking areas (including blanking lines, frame synchronization, etc.).

[0049] Figure 6 FIG. 1 is a schematic diagram showing the phase relationship between the analog camera video signal and the analog camera power consumption current according to an embodiment of the present invention. Figure 6 As shown in FIG. 1 , the relationship between the ISP (Image Signal Processing) module in the simulated camera and the video stream processing is shown. In the frame blanking area, the ISP has no video stream to process, and the camera's power supply current will have a large drop with a drop amplitude of △i.

[0050] Figure 7 FIG. 1 is a schematic diagram showing interference with the video signal when the analog camera is centrally powered according to an embodiment of the present invention. Figure 7 As shown, in the frame blanking area, the load current of the first camera, that is, the power supply current, drops, and the corresponding component of the power supply current also drops, that is, I b1 When the voltage across the terminal sampling resistor R-1 of the DVR channel corresponding to the first analog camera drops, the voltage across the terminal sampling resistor R-1 decreases, causing the video corresponding to the second analog camera to become darker. However, because the first analog camera is in the frame blanking area, the effect cannot be seen by the naked eye. At the same time, the voltage across the terminal sampling resistor R-2 of the DVR channel corresponding to the second analog camera increases, and the increase in the voltage across the terminal sampling resistor R-2 causes the video corresponding to the second analog camera to become brighter, i.e., horizontal stripes appear on the video. Similarly, when the second analog camera is in the frame blanking area, it will also affect the video display of the first analog camera.

[0051] In the technical solution provided in the above steps S202 to S206, a first compensation current signal is obtained, and the load current signal of the first analog camera is compensated by the first compensation current signal to obtain a first target current signal. The first target current signal remains constant, and the component corresponding to the load current (power supply current) after compensation also remains constant, that is, I b1 (ie the first component current signal) remains constant and does not affect the video display of the second analog camera.

[0052] Through the present invention, the first load current signal of the first camera is compensated by the first compensation current signal, and the first target current signal obtained after compensation is constant. Therefore, the first component signal of the first target current signal is also kept constant and will not fluctuate in the frame blanking area of the video signal. Therefore, it will not interfere with the normal image display of other analog cameras, that is, no horizontal stripes will appear when the image is displayed. Therefore, the problem in the related art that the fluctuation of the load current of the analog camera affects the image quality of other analog cameras when the analog cameras are centrally powered is solved, and the effect of avoiding the appearance of horizontal stripes in the images taken by each analog camera when the analog cameras are centrally powered is achieved.

[0053] In an exemplary embodiment, obtaining a first compensation current signal corresponding to a current state of a first analog camera includes: obtaining the current state of the first analog camera; when the current state of the first analog camera is the first state, determining a first initial compensation voltage signal corresponding to the first state of the first analog camera according to a preset set of correspondences, wherein each correspondence in the set of correspondences is a correspondence between a state of the first analog camera and an initial compensation voltage signal determined under the state, and the first initial compensation voltage signal is an initial compensation voltage signal determined based on a load current signal of the first analog camera when the camera is in the first state; and performing signal processing on the first initial compensation voltage signal to obtain the first compensation current signal.

[0054] In this embodiment, the state of the analog camera refers to the output state of the analog camera, and the output state includes at least one of the following information: video mode, frame rate, resolution, and HDR (High Dynamic Imaging). Since the dynamic power consumption of the analog camera in various output states is regular, the dynamic power consumption under different output states, i.e., the load current signal, can be pre-collected, and the corresponding compensation signal can be calculated and stored.

[0055] According to the current state of the first analog camera, when the current state is the first state, it is determined that the pre-stored initial compensation voltage signal corresponding to the current state is the first initial compensation voltage signal.

[0056] It should be noted that the first initial compensation voltage signal is obtained by setting the output state of the analog camera to the first state during research and development, measuring the load current signal of the analog camera at this time, and calculating the corresponding first initial compensation voltage signal based on the load current signal, and storing it in association with the first state.

[0057] Since the compensation is performed on the load current signal and the compensation voltage signal is stored in the form of a digital signal, the first initial compensation voltage signal needs to be processed to obtain the first compensation current signal before the first load current signal can be compensated.

[0058] In an exemplary embodiment, signal processing is performed on the first initial compensation voltage signal to obtain the first compensation current signal, including: performing gain correction on the first initial compensation voltage signal according to the current power supply voltage of the first analog camera to obtain a target correction signal, wherein the current power supply voltage is the power supply voltage provided by the target power supply to the first analog camera through the first power input port; converting the target correction signal into a target compensation voltage signal through a digital-to-analog converter in the first analog camera; and converting the target compensation voltage signal into the first compensation current signal through a voltage-controlled current source unit in the first analog camera.

[0059] In this embodiment, the signal processing of the first initial compensation voltage signal includes three steps: gain correction, digital-to-analog conversion, and voltage-to-current conversion.

[0060] Since the first initial compensation voltage signal is calculated after measuring the load current signal of the analog camera in the research and development stage, and when measuring the load current signal of the analog camera in the research and development stage, the voltage value providing power to the analog camera is a preset power supply voltage, and in the subsequent application of the analog camera, the voltage of the power supply device (i.e., the target power supply) is not necessarily the preset power supply voltage, the first initial compensation voltage signal is scaled, i.e., gain correction is performed, to obtain a target correction signal, so that the compensation of the load current signal is more accurate.

[0061] In addition, the pre-stored signal is a digital signal, while the first load current signal is an analog signal. Therefore, when compensating the first load current signal, the analog signal should be used for compensation, and the target correction signal needs to be converted from a digital signal to an analog signal.

[0062] Since the analog signal output by the built-in digital-to-analog converter of the analog camera is a voltage signal, and the current signal needs to be compensated, it is necessary to convert the voltage signal into the current signal, that is, convert the target compensation voltage signal into a first compensation current signal through the voltage-controlled current source unit.

[0063] In an exemplary embodiment, the initial compensation voltage signal is gain corrected according to the current power supply voltage of the first analog camera to obtain a target correction signal, including: obtaining the current power supply voltage and a preset power supply voltage of the first analog camera, wherein the preset power supply voltage is the power supply voltage provided to the first analog camera when determining the first initial compensation voltage signal; determining the ratio of the preset power supply voltage to the current power supply voltage as a target coefficient; and scaling the initial compensation voltage signal by the target coefficient to obtain the target correction signal.

[0064] In this embodiment, gain correction is performed based on the current power voltage and the preset power voltage currently provided by the target power source to the first analog camera, and a scaling factor, ie, the target factor, is calculated based on the current power voltage and the preset power voltage.

[0065] The scaling factor K is calculated by the following formula scale :

[0066]

[0067] Among them, V calibration is the preset power supply voltage, V in is the current power supply voltage.

[0068] The target correction signal Data is calculated using the following formula dac :

[0069] Data dac =Data rom *K scale

[0070] Among them, Data rom is the first initial compensation voltage signal.

[0071] In an exemplary embodiment, the target correction signal is converted into a target compensation voltage signal by a digital-to-analog converter in the first analog camera, including: obtaining a preset maximum output voltage and a preset accuracy parameter of the digital-to-analog converter; and performing digital-to-analog conversion on the target correction signal according to the preset maximum output voltage and the preset accuracy parameter to obtain the target compensation voltage signal.

[0072] In this embodiment, the digital-to-analog converter is used to convert a digital signal into an analog signal. The following relationship exists between the data of the digital-to-analog converter, the input digital voltage signal, and the output analog voltage signal:

[0073]

[0074] Among them, Data dacis the target correction signal, that is, the input digital voltage signal, n is the preset accuracy parameter, for example, for a 12-bit DAC, then n = 12, Vmax dac is the preset maximum output voltage of the DAC, V dac is the target compensation voltage signal, that is, the output analog voltage signal.

[0075] The target compensation voltage signal can be calculated by transforming the above equation.

[0076] In an exemplary embodiment, converting the target compensation voltage signal into the first compensation current signal by a voltage-controlled current source unit in the first analog camera includes: obtaining a feedback resistance and a voltage drop of the voltage-controlled current source unit; and converting the target compensation voltage signal into the first compensation current signal according to the feedback resistance and the voltage drop.

[0077] In this embodiment, Figure 8 FIG. 1 is a schematic structural diagram of an optional voltage-controlled current source unit according to an embodiment of the present invention. Figure 8 As shown, the output port of the DAC is connected to Figure 8 R1 in the inputs the target compensation voltage signal to the voltage-controlled current source unit, and the voltage-controlled current source unit converts the target compensation voltage signal into a first compensation current signal.

[0078] The first compensation current signal I is calculated by the following formula out :

[0079]

[0080] Among them, V dac The target compensation voltage signal output by the DAC, V drop is the pressure drop of tube Q1, R2 is Figure 8 Feedback resistor, V drop and the resistance value R2 is preset.

[0081] In an exemplary embodiment, the above method also includes: obtaining a load current signal of the first analog camera when it is in the first state; obtaining a maximum load current and a minimum load current in the load current signal of the first analog camera when it is in the first state; obtaining preset accuracy parameters of the digital-to-analog converter in the first analog camera and a feedback resistance and a voltage drop of a voltage-controlled current source unit in the first analog camera; determining the first initial compensation voltage signal corresponding to the first state based on the preset accuracy parameters, the feedback resistance, the voltage drop, the maximum load current and the minimum load current, and establishing a corresponding relationship between the first state and the first initial compensation voltage signal.

[0082] In this embodiment, the pre-stored first initial compensation voltage signal is calculated according to the following method:

[0083] The output state of the first analog camera is set to the first state, the load current signal of the first camera in the first state is collected, and the maximum load current Imax in the load current signal is determined. calibration , during compensation, the load current corresponding to all moments in the load current signal needs to be compensated to the maximum load current. Therefore, the following equation 1 exists:

[0084] I now +I out =Imax calibration

[0085] Among them, Imax calibration is the maximum load current, I now is the load current at the current moment, I out is the compensation current at the current moment.

[0086] Therefore, the compensation current signal in the first state is: I out =Imax calibration -I now .

[0087] The compensated current signal is converted into a compensated voltage signal by the following equation 2:

[0088] V dac =I out *R2+V drop

[0089] Among them, V drop is the pressure drop of tube Q1, R2 is Figure 8 Feedback resistor, V drop The resistance value R2 is preset, and a preset resistance value is obtained by calculation and R2 is set as the preset resistance value.

[0090] When I now At the minimum, the required compensation current is the largest. To allow for sufficient scaling, the compensation current corresponding to half the DAC's maximum output voltage is set as the maximum current required for compensation. This yields Equation 3:

[0091] Vmax dac =[(Imax calibration -Imin calibration )*R2+V drop ]*2

[0092] Among them, Vmax dac Imin is the maximum output voltage of DAC. calibrationThe preset resistance value of R2 can be calculated by the above equation, and R2 in the voltage-controlled current source unit is set to the preset resistance value.

[0093] The following equation 4 exists between the data of the digital-to-analog converter, the input digital voltage signal, and the output analog voltage signal:

[0094]

[0095] Among them, Data rom is the first initial compensation voltage signal, that is, the input digital voltage signal, n is the preset precision parameter, for example, 12-bit DAC, then n = 12, Vmax dac is the preset maximum output voltage of the DAC, V dac The compensation voltage signal is the output analog voltage signal.

[0096] Therefore, the first initial compensation voltage signal is calculated by the following formula:

[0097]

[0098] Among them, Imin calibration is the minimum load current, Imax calibration is the maximum load current, R2 is the preset resistance value in the voltage-controlled current source unit, n is the preset accuracy parameter, V drop is the pressure drop across tube Q1.

[0099] In an exemplary embodiment, the above method also includes: obtaining a second compensation current signal corresponding to the current state of the second analog camera; using the second compensation current signal to compensate the second load current signal of the second analog camera to obtain a second target current signal; transmitting the second target current signal to the negative pole of the second power input port, wherein the second component current signal of the second target current signal flows through the negative pole of the second video output port, the negative pole of the second channel input port, the negative pole of the first channel input port, the negative pole of the first video output port, and the negative pole of the first power input port, and returns to the negative pole of the target power supply, and the second target current signal is used to keep the second component current signal constant.

[0100] In this embodiment, when the second analog camera is in the frame blanking area, it will also affect the video display of the first analog camera. Therefore, the second load current signal of the second camera is compensated by the second compensation current signal. The second target current signal obtained after compensation is constant. Therefore, the second component signal of the second target current signal also remains constant and will not fluctuate in the frame blanking area of the video signal. Therefore, it will not interfere with the normal image display of the first analog camera, that is, no horizontal stripes will appear in the image display.

[0101] Obviously, the embodiments described above are only part of the embodiments of the present invention, rather than all the embodiments.

[0102] The present invention will be specifically described below in conjunction with the embodiments:

[0103] Figure 9 FIG. 1 is a schematic diagram of the structure of a compensation system for analog camera current signals according to an embodiment of the present invention. Figure 9 As shown, it includes the following parts:

[0104] Storage unit 902: used to store initial compensation voltage signals corresponding to different output states of the analog camera;

[0105] Control unit 903: used to read the initial compensation voltage signal from the storage unit, perform gain correction on the initial compensation voltage signal according to the current power supply voltage (the smaller the voltage, the greater the device load current), obtain the target correction signal, and output the target correction signal through the IIS digital interface based on the row and frame synchronization signals of the image sensor at this time as the starting moment.

[0106] The video output signal of the analog camera is output line by line. There is a synchronization level at the beginning of each line, and a frame synchronization signal at the beginning and end of each frame. Since the video signal is output by the ISP module in the control unit, the control unit can obtain the frame and line synchronization signal of the image. When the synchronization signal is output for each frame or each line, the control unit outputs the target correction signal through the IIS digital interface, which is converted into a compensation current signal and then compensated for the load current signal.

[0107] Audio unit 904: Converts the target correction signal output by the master control's IIS into an analog target compensation voltage signal. The audio unit refers to the codec audio processing chip, which internally includes audio capture and output functions. Analog cameras only use the audio capture module, leaving the audio output module unused. The audio output module contains a digital-to-analog converter that converts digital signals into analog signals.

[0108] Voltage-controlled current source unit 905: After compensation, the analog camera load current needs to be stable, so the compensation voltage signal is converted into a compensation current signal through the voltage-controlled current source unit. The compensation current signal output by the voltage-controlled current source unit compensates the load current signal of the analog camera.

[0109] Image sensor 906: an image acquisition module that simulates a camera.

[0110] Power supply 901: power supply module of the analog camera.

[0111] Figure 10 FIG. 1 is an overall flow chart of a current signal compensation method according to an embodiment of the present invention. Figure 10 As shown, the following steps are included:

[0112] Step S1001 : After the simulated camera is powered on, the main controller identifies the output status, where the output status includes at least one of the following information: video mode, frame rate, resolution, and HDR (High Dynamic Imaging).

[0113] Step S1002, reading the corresponding initial compensation voltage signal from the storage unit;

[0114] Step S1003: Calculate the zoom factor K of the analog camera based on the collected current power supply voltage. scale , perform gain correction on the initial compensation voltage signal to obtain the target correction signal;

[0115] Step S1004, after waiting for the frame synchronization signal to arrive, start outputting the target correction signal;

[0116] Step S1005, determining whether the control unit has a built-in digital-to-analog converter. If the control unit has a built-in digital-to-analog converter, executing step S1006; otherwise, executing step S1007;

[0117] Step S1006 , outputting a target compensation voltage signal from a built-in digital-to-analog converter of the control unit;

[0118] Step S1007 , outputting a target compensation voltage signal from the built-in digital-to-analog converter of the audio unit;

[0119] In step S1008 , the voltage-controlled current source unit converts the target compensation voltage signal into a first compensation current signal.

[0120] Figure 11 is a timing diagram of current signal compensation according to an embodiment of the present invention, such as Figure 11As shown, the analog video signal is output line by line, there is a synchronization level at the beginning of each line, and there is a frame synchronization signal at the beginning and end of each frame. When the analog video signal is output, the power consumption of the analog camera device will be sharply reduced, causing the power supply current (i.e., load current) to fluctuate violently, corresponding to the uncorrected device current waveform in the figure, affecting the image quality of the device.

[0121] When each frame and each line outputs the synchronization signal, the load current is compensated by the voltage-controlled current source unit (such as the DAC outputs the compensation waveform). The compensated load current remains constant, corresponding to Figure 11 The corrected current waveform avoids a sharp decrease in the power consumption current of the analog camera and stabilizes the power consumption current of the analog camera to solve the horizontal stripe problem caused by centralized power supply.

[0122] Through the description of the above embodiments, those skilled in the art can clearly understand that the method according to the above embodiment can be implemented by means of software plus the necessary general hardware platform, and of course it can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes a number of instructions for enabling a terminal device (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods described in each embodiment of the present invention.

[0123] In this embodiment, a current signal compensation device is also provided. Figure 12 is a structural block diagram of a current signal compensation device according to an embodiment of the present invention, such as Figure 12 As shown, the device includes:

[0124] A first acquiring unit 1202 acquires a first compensation current signal corresponding to a current state of a first analog camera, wherein a first power input port of the first analog camera is connected to a target power supply, a second power input port of the second analog camera is connected to the target power supply, a first video output port of the first analog camera is connected to a first channel input port of a digital video recorder, and a second video output port of the second analog camera is connected to a second channel input port of the digital video recorder;

[0125] a compensation unit 1204 that compensates a first load current signal of the first analog camera using the first compensation current signal to obtain a first target current signal;

[0126] The transmission unit 1206 transmits the first target current signal to the negative pole of the first power input port, wherein the first component current signal of the first target current signal flows through the negative pole of the first video output port, the negative pole of the first channel input port, the negative pole of the second channel input port, the negative pole of the second video output port, and the negative pole of the second power input port, and returns to the negative pole of the target power supply. The first target current signal is used to keep the first component current signal constant.

[0127] In an exemplary embodiment, the above-mentioned first acquisition unit includes: a first acquisition module, used to obtain the current state of the first analog camera; a first determination module, when the current state of the first analog camera is the first state, determines the first initial compensation voltage signal corresponding to the first state of the first analog camera according to a preset set of correspondences, wherein each correspondence in the set of correspondences is a correspondence between a state of the first analog camera and an initial compensation voltage signal determined under the state, and the first initial compensation voltage signal is an initial compensation voltage signal determined based on the load current signal of the first analog camera when it is in the first state; a signal processing module, used to perform signal processing on the initial compensation voltage signal to obtain the first compensation current signal.

[0128] In an exemplary embodiment, the above-mentioned signal processing module includes: a correction module, used to perform gain correction on the initial compensation voltage signal according to the current power supply voltage of the first analog camera to obtain a target correction signal, wherein the current power supply voltage is the power supply voltage provided by the target power supply to the first analog camera through the first power input port; a first conversion module, used to convert the target correction signal into a target compensation voltage signal through a digital-to-analog converter in the first analog camera; and a second conversion module, used to convert the target compensation voltage signal into the first compensation current signal through a voltage-controlled current source unit in the first analog camera.

[0129] In an exemplary embodiment, the correction module is also used to obtain the current power supply voltage and the preset power supply voltage of the first analog camera, wherein the preset power supply voltage is the power supply voltage provided to the first analog camera when determining the first initial compensation voltage signal; the ratio of the preset power supply voltage to the current power supply voltage is determined as a target coefficient; and the initial compensation voltage signal is scaled by the target coefficient to obtain the target correction signal.

[0130] In an exemplary embodiment, the first conversion module is further used to obtain a preset maximum output voltage and a preset accuracy parameter of the digital-to-analog converter; and perform digital-to-analog conversion on the target correction signal according to the preset maximum output voltage and the preset accuracy parameter to obtain the target compensation voltage signal.

[0131] In an exemplary embodiment, the second conversion module is further configured to obtain a feedback resistance and a voltage drop of the voltage-controlled current source unit; and convert the target compensation voltage signal into the first compensation current signal according to the feedback resistance and the voltage drop.

[0132] In an exemplary embodiment, the above-mentioned device is used to obtain the load current signal of the first analog camera when it is in the first state; obtain the maximum load current and the minimum load current in the load current signal of the first analog camera when it is in the first state; obtain the preset accuracy parameters of the digital-to-analog converter in the first analog camera and the feedback resistance and voltage drop of the voltage-controlled current source unit in the first analog camera; determine the first initial compensation voltage signal corresponding to the first state based on the preset accuracy parameters, the feedback resistance, the voltage drop, the maximum load current and the minimum load current, and establish a corresponding relationship between the first state and the first initial compensation voltage signal.

[0133] In an exemplary embodiment, the above-mentioned device is used to obtain a second compensation current signal corresponding to the current state of the second analog camera; use the second compensation current signal to compensate the second load current signal of the second analog camera to obtain a second target current signal; transmit the second target current signal to the negative pole of the second power input port, wherein the second component current signal of the second target current signal flows through the negative pole of the second video output port, the negative pole of the second channel input port, the negative pole of the first channel input port, the negative pole of the first video output port, and the negative pole of the first power input port, and returns to the negative pole of the target power supply, and the second target current signal is used to keep the second component current signal constant.

[0134] It should be noted that the above modules can be implemented through software or hardware. For the latter, it can be implemented in the following ways, but not limited to: the above modules are all located in the same processor; or the above modules are located in different processors in any combination.

[0135] An embodiment of the present invention further provides a computer-readable storage medium, in which a computer program is stored. The computer program is configured to execute the steps of any one of the above method embodiments when running.

[0136] In an exemplary embodiment, the computer-readable storage medium may include, but is not limited to, various media that can store computer programs, such as a USB flash drive, a read-only memory (ROM), a random access memory (RAM), a mobile hard disk, a magnetic disk, or an optical disk.

[0137] An embodiment of the present invention further provides an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor is configured to run the computer program to execute the steps in any one of the above method embodiments.

[0138] In an exemplary embodiment, the electronic device may further include a transmission device and an input / output device, wherein the transmission device is connected to the processor, and the input / output device is connected to the processor.

[0139] For specific examples in this embodiment, reference may be made to the examples described in the above embodiments and exemplary implementation modes, and this embodiment will not be described in detail here.

[0140] Obviously, those skilled in the art will appreciate that the various modules or steps of the present invention described above can be implemented using a general-purpose computing device, can be centralized on a single computing device, or can be distributed across a network of multiple computing devices. They can be implemented using program code executable by the computing device, and thus, can be stored in a storage device and executed by the computing device. In some cases, the steps shown or described herein can be performed in a different order than that shown, or can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, the present invention is not limited to any particular combination of hardware and software.

[0141] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A current signal compensation method, characterized in that: include: Obtaining a first compensation current signal corresponding to a current state of a first analog camera, wherein a first power input port of the first analog camera is connected to a target power supply, a second power input port of the second analog camera is connected to the target power supply, a first video output port of the first analog camera is connected to a first channel input port of a digital video recorder, and a second video output port of the second analog camera is connected to a second channel input port of the digital video recorder; Using the first compensation current signal to compensate for the first load current signal of the first analog camera to obtain a first target current signal, wherein the first target current signal remains constant; The method also includes: when the current state of the first analog camera is the first state, determining a first initial compensation voltage signal corresponding to the first state of the first analog camera according to a preset set of corresponding relationships; performing gain correction on the first initial compensation voltage signal according to the current power supply voltage of the first analog camera to obtain a target correction signal, wherein the current power supply voltage is the power supply voltage provided by the target power supply to the first analog camera through the first power input port; converting the target correction signal into a target compensation voltage signal through a digital-to-analog converter in the first analog camera; and converting the target compensation voltage signal into the first compensation current signal through a voltage-controlled current source unit in the first analog camera.

2. The method according to claim 1, characterized in that The obtaining of a first compensation current signal corresponding to a current state of the first analog camera includes: Obtaining the current state of the first analog camera; When the current state of the first analog camera is the first state, determining the first initial compensation voltage signal corresponding to the first state of the first analog camera according to a preset set of correspondences, wherein each correspondence in the set of correspondences is a correspondence between a state of the first analog camera and an initial compensation voltage signal determined in the state, and the first initial compensation voltage signal is an initial compensation voltage signal determined based on a load current signal of the first analog camera in the first state; Signal processing is performed on the first initial compensation voltage signal to obtain the first compensation current signal.

3. The method according to claim 2, characterized in that The performing signal processing on the first initial compensation voltage signal to obtain the first compensation current signal includes: performing gain correction on the first initial compensation voltage signal according to a current power supply voltage of the first analog camera to obtain the target correction signal, wherein the current power supply voltage is a power supply voltage provided by the target power supply to the first analog camera through the first power input port; converting the target correction signal into the target compensation voltage signal through a digital-to-analog converter in the first analog camera; The target compensation voltage signal is converted into the first compensation current signal by a voltage-controlled current source unit in the first analog camera.

4. The method according to claim 3, characterized in that The step of performing gain correction on the initial compensation voltage signal according to the current power supply voltage of the first analog camera to obtain the target correction signal includes: acquiring a current power supply voltage and a preset power supply voltage of the first analog camera, wherein the preset power supply voltage is a power supply voltage provided to the first analog camera when determining the first initial compensation voltage signal; determining a ratio of the preset power supply voltage to the current power supply voltage as a target coefficient; The initial compensation voltage signal is scaled by the target coefficient to obtain the target correction signal.

5. The method according to claim 3, characterized in that The converting the target correction signal into the target compensation voltage signal by a digital-to-analog converter in the first analog camera includes: Obtaining a preset maximum output voltage and a preset accuracy parameter of the digital-to-analog converter; According to the preset maximum output voltage and the preset accuracy parameter, the target correction signal is converted into a digital-to-analog format to obtain the target compensation voltage signal.

6. The method according to claim 3, characterized in that The converting the target compensation voltage signal into the first compensation current signal by the voltage-controlled current source unit in the first analog camera includes: Obtaining the feedback resistance and voltage drop of the voltage-controlled current source unit; The target compensation voltage signal is converted into the first compensation current signal according to the feedback resistor and the voltage drop.

7. The method according to claim 2, characterized in that The method further comprises: obtaining a load current signal of the first analog camera when the first analog camera is in the first state; obtaining a maximum load current and a minimum load current in a load current signal of the first analog camera when the camera is in the first state; Obtaining preset accuracy parameters of a digital-to-analog converter in the first analog camera and a feedback resistance and a voltage drop of a voltage-controlled current source unit in the first analog camera; The first initial compensation voltage signal corresponding to the first state is determined according to the preset accuracy parameter, the feedback resistor, the voltage drop, the maximum load current, and the minimum load current, and a corresponding relationship between the first state and the first initial compensation voltage signal is established.

8. The method according to any one of claims 1 to 7, characterized in that The method further comprises: Obtaining a second compensation current signal corresponding to the current state of the second analog camera; Compensating the second load current signal of the second analog camera using the second compensation current signal to obtain a second target current signal; The second target current signal is transmitted to the negative pole of the second power input port, wherein the second component current signal of the second target current signal flows through the negative pole of the second video output port, the negative pole of the second channel input port, the negative pole of the first channel input port, the negative pole of the first video output port, and the negative pole of the first power input port, and returns to the negative pole of the target power supply, and the second target current signal is used to keep the second component current signal constant.

9. A current signal compensation device, characterized in that: include: a first acquiring unit configured to acquire a first compensation current signal corresponding to a current state of a first analog camera, wherein a first power input port of the first analog camera is connected to a target power supply, a second power input port of the second analog camera is connected to the target power supply, a first video output port of the first analog camera is connected to a first channel input port of a digital video recorder, and a second video output port of the second analog camera is connected to a second channel input port of the digital video recorder; a compensation unit, which uses the first compensation current signal to compensate the first load current signal of the first analog camera to obtain a first target current signal, wherein the first target current signal remains constant; The device is also used to: when the current state of the first analog camera is the first state, determine the first initial compensation voltage signal corresponding to the first state of the first analog camera according to a preset set of corresponding relationships; perform gain correction on the first initial compensation voltage signal according to the current power supply voltage of the first analog camera to obtain a target correction signal, wherein the current power supply voltage is the power supply voltage provided by the target power supply to the first analog camera through the first power input port; convert the target correction signal into a target compensation voltage signal through a digital-to-analog converter in the first analog camera; and convert the target compensation voltage signal into the first compensation current signal through a voltage-controlled current source unit in the first analog camera.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, wherein when the computer program is executed by a processor, the steps of the method described in any one of claims 1 to 8 are implemented.

11. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 8 are implemented.

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