Camera frame rate exposure time tester calibration method and system

Abstract

The invention relates to the technical field of camera measurement, in particular to a calibration system and method for a camera frame rate exposure time tester, and the system comprises a photoelectric detector, an XY scanning mechanism, a stepping motor controller, an electrical parameter analysis device, a frequency meter, a computer, an atomic frequency standard device, a light collimation coupler and a spectrum analyzer. The XY scanning mechanism is controlled by the stepping motor controller to carry out scanning motion, and the XY scanning mechanism controls the photoelectric detector and the light collimation coupler to carry out scanning measurement on a light emitting diode signal emission array of the detected camera frame rate exposure time tester. And the computer is used for collecting electrical parameter measurement data output by the electrical parameter analysis equipment and optical parameter measurement data output by the spectrometer, calculating a measurement error of the camera frame rate exposure time tester and correcting a display value error of the camera frame rate exposure time tester. According to the invention, each parameter of the camera frame rate exposure time tester can be automatically calibrated, and the accuracy of the camera frame rate exposure time tester is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of camera measurement, and in particular to a camera frame rate exposure time tester calibration system and method. Background Art

[0002] In recent years, with the development of CCD, CMOS image sensors and optical lens technology, electronic devices with imaging functions have become more and more popular in people's lives. In addition to traditional digital cameras, camcorders, mobile phones, and tablet computers, new camera forms such as unmanned aerial vehicles, sports cameras, security surveillance cameras, car driving recording cameras, and advanced car assistance cameras have emerged. The camera function of consumer electronics such as mobile phones is also developing towards high pixels, multiple cameras, and large sensors. The application of cameras in life is becoming more and more extensive.

[0003] Camera frame rate exposure time testers are widely used in consumer electronics, image quality evaluation, security monitoring and other fields. my country is currently a major consumer electronics production country in the world. In 2021, mobile phone shipments were nearly 500 million units, accounting for more than 35% of global mobile phone shipments. Currently, consumers are paying more and more attention to the camera functions of mobile phones and other products. Intellectual property protection of this technology can effectively ensure the quality of my country's consumer electronics products and increase the international market share of our products.

[0004] Currently, there is a frame rate tester for an imaging device, which includes a main board and a key board, wherein the main board includes an LED array, a knob and a touch display screen, and the key board includes at least two keys for selecting different operating modes; an external timer is used to simulate pulse width modulation; during the light-emitting operation of the LED array, different operating modes of the LED array are selected by touching the display screen and keys, and the required test frequency and test time corresponding to different operating modes are adjusted by adjusting the knob; the imaging device is aimed at the LED array, and when the LED array operates in different operating modes, the operating status of the LED array during the operation process is photographed respectively; based on the corresponding operating status of the LED array in different operating modes, the shooting properties of the imaging device are calculated, so that the imaging device completes the test when photographing the operating status of the LED array, and the shooting properties of the imaging device are accurately calculated.

[0005] The camera frame rate exposure time tester is mainly used to test the frame rate, exposure time, and response time parameters of cameras and webcams. It is generally composed of three parts: a light-emitting diode array, a control unit, and a display unit. It is widely used in the research and development and production of consumer electronics such as mobile phones, tablets, cameras, and webcams, as well as image quality evaluation and testing, security monitoring, and other fields. It is currently the main means of testing camera frame rate and time parameters. Due to the influence of temperature drift and aging on the crystal oscillator inside the camera frame rate exposure time tester, its display value has a large error after a period of use. In order to improve the accuracy of the camera frame rate exposure time tester, a system and method for calibrating the relevant parameters of the camera frame rate exposure time tester is needed. Summary of the invention

[0006] In order to solve the technical problems existing in the prior art, the present invention provides a camera frame rate exposure time tester calibration system and method, which can effectively shield the interference of bypass light and ambient light during the calibration process, greatly reduce the requirements for the calibration environment lighting conditions, and can perform on-site automatic calibration to achieve automatic calibration of various parameters of the camera frame rate exposure time tester, thereby improving the accuracy of the camera frame rate exposure time tester.

[0007] A first object of the present invention is to provide a camera frame rate exposure time tester calibration system.

[0008] A second object of the present invention is to provide a camera frame rate exposure time tester calibration method.

[0009] The present invention can be achieved by adopting the following technical solutions:

[0010] A camera frame rate exposure time tester calibration system comprises a photoelectric detector, an XY scanning mechanism, a stepper motor controller, an electrical parameter analysis device, a frequency meter, a computer, an atomic frequency standard device, an optical collimation coupler, and a spectrum analyzer. The photoelectric detector and the optical collimation coupler are both connected to the XY scanning mechanism, the electrical parameter analysis device is respectively connected to the photoelectric detector, the atomic frequency standard device, and the computer, and the spectrum analyzer is respectively connected to the optical collimation coupler and the computer.

[0011] The photoelectric detector is used to convert the frame rate and time optical signals output by the frame rate exposure time tester of the camera under inspection into electrical signals and input them into the electrical parameter analysis equipment; the electrical parameter analysis equipment is used to receive the output signal of the photoelectric detector, measure the electrical parameters of the output signal of the photoelectric detector, and output the electrical parameter measurement data to the computer;

[0012] The optical collimation coupler is used to collimate the optical signal output by the camera frame rate exposure time tester and couple it to the spectrometer. The spectrometer is used to receive and measure the optical parameters of the optical signal output by the camera frame rate exposure time tester and output the optical parameter measurement data to the computer.

[0013] The stepper motor controller is connected to the XY scanning mechanism and the computer respectively. The stepper motor controller is controlled by the computer to make the XY scanning mechanism perform scanning motion according to a preset path. The XY scanning mechanism is used to scan the light emitting diode signal emission array of the frame rate exposure time tester of the camera under test one by one using the photoelectric detector and the light collimation coupler along the predetermined moving path.

[0014] The computer is used to collect and record the electrical parameter measurement data output by the electrical parameter analysis equipment and the optical parameter measurement data output by the spectrometer, calculate the measurement error of the camera frame rate exposure time tester, and correct the display value of the camera frame rate exposure time tester.

[0015] Preferably, the photoelectric detector includes a detector, a lens and a conical reflector barrel, the lens is arranged between the light input port of the detector and the conical reflector barrel, the conical reflector barrel is fixed on the outer shell of the detector, the conical reflector barrel includes a first end hole and a second end hole, the diameter of the first end hole is smaller than the diameter of the second end hole, and the second end hole of the conical reflector barrel surrounds the light input port of the detector.

[0016] Preferably, the interior of the conical reflective lens barrel is coated with a light reflective coating for reflecting the output light of the camera frame rate exposure time tester, and the exterior of the conical reflective lens barrel is coated with a black light-proof coating.

[0017] Preferably, the XY scanning mechanism includes a horizontal X-axis moving arm, a vertical Y-axis moving arm, a rotating mechanism and a motor group, the horizontal X-axis moving arm is vertically connected to the vertical Y-axis moving arm, the rotating mechanism is vertically connected to the vertical Y-axis moving arm, and the photodetector and the optical collimation coupler are detachably arranged on the rotating mechanism.

[0018] Preferably, the motor group includes an X-axis motor, a Y-axis motor and a rotary motor, the X-axis motor is used to control the vertical Y-axis movable arm to move on the horizontal X-axis movable arm, the Y-axis motor is used to control the rotary mechanism to move on the vertical Y-axis movable arm, and the rotary motor is used to control the rotary mechanism to rotate.

[0019] Preferably, the electrical parameter analysis device is an oscilloscope or a frequency meter.

[0020] A camera frame rate exposure time tester calibration method is implemented based on the above-mentioned camera frame rate exposure time tester calibration system, comprising the steps of:

[0021] S1. Measure and calibrate the electrical parameters of the camera frame rate exposure time tester:

[0022] The XY scanning mechanism is controlled by a computer and a stepping motor controller to perform scanning motion according to a preset path, and the photoelectric detector is detachably arranged on the rotating mechanism of the XY scanning mechanism;

[0023] The LED lamp beads of the light emitting diode signal emission array of the camera frame rate exposure time tester under inspection are scanned and measured one by one by a photoelectric detector, and the light signals of the LED lamp beads of the light emitting diode signal emission array are converted into electrical signals and input into an electrical parameter analysis device, and the electrical parameter analysis device measures the electrical parameters of the output signal of the photoelectric detector and outputs the electrical parameter measurement data to a computer;

[0024] The electrical parameter measurement data output by the electrical parameter analysis device is collected and recorded by a computer, the indication error or relative error of the electrical parameter of the camera frame rate exposure time tester is calculated, and the camera frame rate exposure time tester is calibrated so that the display value of the electrical parameter is consistent with the reference value;

[0025] S2. Measure and calibrate the optical parameters of the camera frame rate exposure time tester:

[0026] The XY scanning mechanism is controlled by a computer and a stepping motor controller to perform scanning motion according to a preset path, and the optical collimation coupler is detachably arranged on the rotating mechanism of the XY scanning mechanism;

[0027] The LED lamp beads of the light emitting diode signal emission array of the camera frame rate exposure time tester under inspection are scanned and measured one by one through an optical collimation coupler, and the optical signals of the LED lamp beads of the light emitting diode signal emission array are collimated and coupled to the spectrometer, and the spectrometer measures the optical parameters of the optical signals of the LED lamp beads and outputs the optical parameter measurement data to a computer;

[0028] The optical parameter measurement data output by the spectrometer is collected and recorded by a computer, the indication error or relative error of the optical parameter of the camera frame rate exposure time tester is calculated, and the camera frame rate exposure time tester is calibrated so that the displayed value of its optical parameter is consistent with the reference value.

[0029] Preferably, the computer determines the difference between a certain optical parameter or electrical parameter of the camera frame rate exposure time tester and a reference value according to the indication error or relative error of the camera frame rate exposure time tester, controls the camera frame rate exposure time tester through the computer to adjust its internal crystal oscillator frequency according to the indication error or relative error, and calls the control software to modify the display value of the camera frame rate exposure time tester so that the display value of the camera frame rate exposure time tester is consistent with the reference value.

[0030] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0031] The present invention proposes a calibration method and system for a camera frame rate exposure time tester. A photoelectric detector using a conical emission tube and a lens can effectively shield the interference of bypass light signals and ambient light noise during the calibration process, thereby improving the calibration accuracy and greatly reducing the requirements for the calibration environment and calibration equipment during the calibration process. There is no need to place the calibration in an optical darkroom, and the calibration is convenient for on-site calibration. An XY scanning mechanism and a motor controller using a "Z"-shaped scanning scheme can automatically align and calibrate the signal light array of the camera frame rate exposure time tester one by one, thereby greatly improving the calibration efficiency, solving the problem that the current camera frame rate exposure time tester lacks an effective calibration method and system, and improving the accuracy of the camera frame rate exposure time tester. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0033] Figure 1 This is the appearance of the existing camera frame rate exposure time tester and its lamp bead time domain waveform diagram;

[0034] Figure 2 is a schematic diagram of a method for calibrating electrical parameters of a camera frame rate exposure time tester in an embodiment of the present invention;

[0035] Figure 3 Schematic diagram of the design of the conical reflector tube photoelectric detector in an embodiment of the present invention;

[0036] Figure 4 is a schematic diagram of optical simulation results of a conical reflector barrel plus a lens design in an embodiment of the present invention;

[0037] Figure 5 It is a structural schematic diagram of an XY scanning mechanism plus a photoelectric detector in an embodiment of the present invention;

[0038] Figure 6 is a structural schematic diagram of an XY scanning mechanism plus a light collimation coupler in an embodiment of the present invention;

[0039] Figure 7 is a schematic diagram of a "Z"-shaped scanning solution in an embodiment of the present invention;

[0040] The numbers in the figure are: 1-detector, 2-lens, 3-conical reflection lens barrel, 4-horizontal X-axis moving arm, 5-vertical Y-axis moving arm, 6-rotation mechanism, 7-motor group, 8 photodetector, 9-optical collimation coupler, 10-optical fiber. DETAILED DESCRIPTION

[0041] The technical solution of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is obvious that the described embodiments are part of the embodiments of the present invention, not all of the embodiments, and the implementation of the present invention is not limited to this. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0042] For imaging devices, the response time is defined as the time from pressing the shutter button to the imaging device starting to acquire images, and the exposure time is defined as the time from the imaging device starting to acquire images to the end of acquisition.

[0043] like Figure 1 As shown in the figure, the appearance of the existing camera frame rate exposure time tester and its lamp bead time domain waveform diagram, taking the frame rate tester with a 10*10 scale LED array as an example, in the response time and exposure time measurement mode, the LED array lights up from lamp bead No. 0 in the upper left corner to lamp bead No. 9 in sequence, then from the second row to the tenth row, and then it is the turn of lamp bead No. 0 in the upper left corner to light up, and so on. The lighting time t of a single lamp bead is defined as the unit time. When testing the response time and exposure time of the imaging device, the imaging device shoots the flashing LED array of the frame rate tester, and calculates the exposure time by multiplying the number of lit lamp beads by the unit time t. From the image taken by the imaging device, the number of unlit lamp beads between lamp bead No. 0 and the first lit lamp bead multiplied by the unit time t is used to obtain the response time.

[0044] Embodiment 1:

[0045] like Figure 2 As shown, a camera frame rate exposure time tester calibration system described in the present invention includes a photoelectric detector, an XY scanning mechanism, a stepper motor controller, an electrical parameter analysis device, a frequency meter, a computer, an atomic frequency standard device, an optical collimation coupler, and a spectrum analyzer. The photoelectric detector, the optical collimation coupler, and the stepper motor controller are all connected to the XY scanning mechanism, the electrical parameter analysis device is respectively connected to the photoelectric detector, the atomic frequency standard device, and the computer, and the spectrum analyzer is respectively connected to the optical collimation coupler and the computer.

[0046] The photodetector is used to convert the frame rate and time optical signals output by the frame rate exposure time tester of the camera under test into electrical signals and input them into the electrical parameter analysis equipment. The photodetector is fixed to the XY scanning mechanism. The photodetector has a coaxial signal output interface for outputting the electrical signal to the electrical parameter analysis equipment. The photodetector may also have a synchronous trigger output port for time base synchronization with the input signal. The coupling mode of the photodetector is spatial optical coupling. According to the LED working wavelength range of the frame rate exposure time tester of the camera under test, a silicon photodetector is selected for the wavelength range of 200nm to 1100nm, and an indium gallium arsenide photodetector is selected for the wavelength range of 800nm ​​to 1700nm.

[0047] like Figure 3 As shown, the photodetector includes a detector 1, a lens 2 and a conical reflector barrel 3, wherein the lens 2 is arranged between the light input port of the detector 1 and the conical reflector barrel 3, the conical reflector barrel is fixed on the housing of the detector, the conical reflector barrel includes a first end hole and a second end hole, the diameter of the first end hole is smaller than the diameter of the second end hole, and the second end hole of the conical reflector barrel surrounds the light input port of the detector. Preferably, a light reflective coating is coated inside the reflector barrel to reflect the output light of the camera frame rate exposure time tester, and a black light-proof coating is coated outside the reflector barrel. The lens is used to collimate and focus the output light of the camera frame rate exposure time tester to maximize the use of signal light.

[0048] In this embodiment, the use of a conical reflector tube plus a lens can effectively shield the interference of bypass light signals and ambient light noise during the calibration process, which can greatly reduce the requirements for ambient light conditions during the calibration process. There is no need to use an optical darkroom, and it can also be carried to the site for calibration. The detector housing is packaged with black anodized matte aluminum alloy to reduce the reflection of stray light. The optical simulation results of the conical reflector tube plus lens design are as follows: Figure 4 shown.

[0049] The XY scanning mechanism is used to scan the light emitting diode signal emission array of the frame rate exposure time tester of the camera under test one by one along a predetermined moving path using a photoelectric detector and a light collimating coupler.

[0050] like Figure 5 As shown, the structural diagram of the XY scanning mechanism plus the photodetector in the embodiment of the present invention is as follows: Figure 6As shown, the structural schematic diagram of the XY scanning mechanism plus the optical collimation coupler in the embodiment of the present invention. The XY scanning mechanism includes a horizontal X-axis moving arm 4, a vertical Y-axis moving arm 5, a rotating mechanism 6 and a motor group 7. The horizontal X-axis moving arm 4 is vertically connected to the vertical Y-axis moving arm 5, and the rotating mechanism 6 is vertically connected to the vertical Y-axis moving arm 5. The photodetector 8 and the optical collimation coupler 9 are detachably arranged on the rotating mechanism 6. The motor group 7 includes an X-axis motor, a Y-axis motor and a rotating motor. The X-axis motor, the Y-axis motor and the rotating motor can all be stepping motors. The X-axis motor is used to control the vertical Y-axis moving arm to move on the horizontal X-axis moving arm, the Y-axis motor is used to control the rotating mechanism to move on the vertical Y-axis moving arm, and the rotating motor is used to control the rotating mechanism to rotate. During the calibration process, the photodetector and the optical collimation coupler are finely adjusted in position; the motor group can control the movement of the photodetector and the optical collimation coupler in three directions: horizontal, vertical and rotation, and has three degrees of freedom. The stepping motor controller is used to control the motor group on the XY scanning mechanism so that the photodetector can scan in a "Z" shape. The stepper motor controller is connected to the computer for communication, and is also connected to several stepper motors on the XY scanning mechanism of the stepper motor controller, and has interfaces and connecting lines for the functions and controls of the stepper motors.

[0051] Specifically, the electrical parameter analysis equipment is an oscilloscope or a frequency meter. The oscilloscope is used to receive the output signal of the photodetector and calibrate the signal's response time, exposure time, shutter time, time interval, duty cycle, pulse width and other parameters. The oscilloscope has more than one input channel, a bandwidth of more than 1 GHz, a sampling rate of more than 2.5 GS / s, and a time base accuracy of 1×10 -6 The above has an external time base reference input interface for accessing a high-precision external atomic frequency standard signal to improve the measurement accuracy of time-frequency parameters.

[0052] The frequency meter is used to receive the output signal of the photodetector. It is used in scenarios with high measurement accuracy requirements to calibrate the frame frequency, response time, exposure time, shutter time, phase, time interval, duty cycle and other parameters of the photodetector output signal. The frequency meter has more than 2 channels of input, a frequency measurement range of more than DC to 200MHz, a display resolution of more than 11 bits, and a time base accuracy of 5×10 -8 The above has the measurement functions of frequency, period, time interval, rise time, fall time, pulse width, phase, duty cycle, etc., and the time resolution is less than 1ns. Furthermore, the frequency meter has an external time base reference input interface for the access of high-precision external atomic frequency standard signals to improve the measurement accuracy of time and frequency parameters, and is compatible with 1MHz, 5MHz, 10MHz and other time synchronization signals.

[0053] The atomic frequency standard is used to lock the time base of the oscilloscope and frequency meter to improve the overall time calibration accuracy of the system. The atomic frequency standard has 1MHz, 5MHz, 10MHz and other time-frequency synchronization signal outputs, which are output through the coaxial interface. The time base accuracy of the atomic frequency standard is 5×10 -11 above.

[0054] The optical collimation coupler is used to collimate the optical signal output by the camera frame rate exposure time tester and couple it into the spectrometer. The input end of the fiber coupler is spatial light coupling input, and the output end can be spatial light coupling output or fiber coupling output according to the receiving port form of the spectrometer. The optical structure of the fiber coupler adopts the form of air gap double cemented lens or double Gauss lens.

[0055] The spectrometer is used to measure the parameters of the optical signal output by the camera frame rate exposure time tester, including the central wavelength, spectral width, optical parameter isotropy, etc. According to the working wavelength range of the LED of the camera frame rate exposure time tester under test, the working wavelength range of the spectrum analyzer is 200nm~1100nm, 800nm~1700nm, and it has an optical signal input interface. Furthermore, the spectrum analyzer has an interface for communicating with a computer, and the spectrum analyzer has measurement functions such as central wavelength, spectral width, optical power, and difference cursor. Specifically, the central wavelength setting of the spectrum analyzer is consistent with the central wavelength of the LED of the camera frame rate exposure time tester under test.

[0056] In this embodiment, the optical parameter isotropy is measured by a spectrometer, and the optical parameter isotropy is calculated according to the following formula:

[0057] ε=I(x) max -I(x) min

[0058] Where: ε is the isotropy of a certain parameter; I(x) max It is the maximum value of a parameter measured by rotating around the geometric center of the LED lamp bead; I(x) min It is the minimum value of a parameter measured by rotating around the geometric center of the LED lamp bead.

[0059] The computer is used to control the stepper motor controller so that the XY scanning mechanism can scan according to the pre-set path plan. The computer is also used to collect measurement data from the oscilloscope, frequency meter, and spectrometer, calculate the indication error or relative error of the camera frame rate exposure time tester, and calibrate the camera frame rate exposure time tester so that its display value is consistent with the reference value. The computer has LAN, USB, RS232, GPIB and other communication interfaces to communicate with the oscilloscope, frequency meter, spectrum analyzer, and stepper motor controller.

[0060] Specifically, the computer determines the difference between a certain parameter of the camera frame rate exposure time tester and a reference value based on the calculated indication error or relative error. The computer controls the camera frame rate exposure time tester through a communication interface to adjust its internal crystal oscillator frequency, and calls the control software to modify the display value of the camera frame rate exposure time tester so that the display value of the camera frame rate exposure time tester is consistent with the reference value, thereby achieving the purpose of correcting the display value error of the camera frame rate exposure time tester.

[0061] In this example, the steps for using the camera frame rate exposure time tester calibration system include:

[0062] Measure and calibrate the electrical parameters of the camera frame rate exposure time tester:

[0063] Step 1: Turn on the frame rate exposure time tester of the camera under test and select a certain working mode;

[0064] Step 2: Control the stepper motor controller through the computer to control the XY scanning mechanism so that the photodetector is aligned with an LED lamp bead of the LED array of the frame rate exposure time tester of the camera under test;

[0065] Step 3: The photodetector converts the optical signal of an LED lamp bead of the LED array into an electrical signal and inputs it into an oscilloscope or a frequency meter. The oscilloscope or the frequency meter is connected to an external atomic frequency standard to improve the measurement accuracy.

[0066] Step 4: The computer reads and records the measurement results from the oscilloscope or frequency meter through the communication interface, calculates the measurement error of the camera frame rate exposure time tester, and corrects the display value of the camera frame rate exposure time tester until the display value of the calibrated instrument is consistent with the indication of the oscilloscope or frequency meter;

[0067] Step 5: The computer controls the stepper motor controller and the stepper motor to aim the photodetector at the next LED lamp bead, repeats steps 3 and 4, and records the measurement results;

[0068] Step 6: Repeat steps 3, 4, and 5 until all the lamp beads in the LED array are measured;

[0069] Step 7: The camera frame rate exposure time tester under test switches to the next working mode, and steps 2 to 6 are repeated until all measurement modes of the camera frame rate exposure time tester under test are measured. The computer records the measurement results, and the display value of the camera frame rate exposure time tester is corrected by the computer until the display value of the calibrated instrument is consistent with the indication of the oscilloscope or frequency meter.

[0070] Measure and calibrate the optical parameters of the camera frame rate exposure time tester:

[0071] Step 1: Turn on the frame rate exposure time tester of the camera under test and select a certain working mode;

[0072] Step 2: The computer controls the stepper motor controller, and the stepper motor controller controls the XY scanning mechanism to align the light collimation coupler with the No. 1 lamp bead of the LED array of the frame rate exposure time tester of the camera under test;

[0073] Step 3: The optical collimation coupler collimates the signal light and inputs it into the spectrum analyzer. The center wavelength of the spectrum analyzer is set to be consistent with the wavelength of the LED lamp bead of the camera frame rate exposure time tester under test. The wavelength scanning width is automatic, and the resolution bandwidth is set to the minimum. The peak mark or spectrum wavelength analysis is used to measure the center wavelength, spectrum width and other parameters.

[0074] Step 4: The computer reads the measurement results from the spectrum analyzer through the communication interface and records them, calculates the measurement error, and corrects the display value of the camera frame rate exposure time tester through the computer until the display value of the calibrated instrument is consistent with the indication of the spectrum analyzer;

[0075] Step 5: Control the rotating mechanism on the XY scanning structure to rotate around the geometric center of the LED lamp bead. The computer reads the parameters of the spectrometer in real time through the communication interface, calculates and records the optical parameters such as the isotropy of light wavelength and the isotropy of light power.

[0076] Step 6: The computer controls the stepper motor controller and the stepper motor to align the light collimation coupler with the No. 2 LED lamp bead, and repeats steps 3 to 5, and records the measurement results;

[0077] Step 7: Repeat steps 3 to 6 until all the lamp beads in the LED array are measured;

[0078] Step 8: The frame rate exposure time test of the camera under test switches to the next working mode, and steps 2 to 7 are repeated until all measurement modes of the frame rate exposure time tester of the camera under test are measured, and the computer records the measurement results; the display value of the camera frame rate exposure time tester is corrected by the computer until the display value of the calibrated instrument is consistent with the indication of the spectrum analyzer.

[0079] like Figure 7As shown, the XY scanning mechanism adopts a "Z"-shaped scanning scheme to calibrate the output signal of the LED array of the camera frame rate exposure time tester. Taking the camera frame rate exposure time tester with a 10*10 LED array as an example, a coordinate system is established with the center of the LED array as the coordinate origin, and the coordinate of the LED No. 1 in the upper left corner is (-5,5). The motor controller controls the motor to make the photodetector reach the (-5,5) coordinate point, and align it with the LED to calibrate its parameters. After the calibration is completed, the controller controls the motor to move with the LED array unit interval as a step length, and moves to the (-4,5) coordinate point, that is, the position of the LED No. 2, and so on. The cycle continues until it reaches the (5,-5) coordinate point, that is, the calibration of the entire LED array of the camera frame rate exposure time tester is completed. Camera frame rate exposure time testers with LED arrays of other types and sizes can refer to this clause for implementation.

[0080] In summary, a camera frame rate exposure time tester calibration system is provided, which can realize automatic calibration of parameters such as frame frequency, response time, exposure time, shutter time, phase, time interval, duty cycle, and center wavelength of the camera frame rate exposure time tester. The design of the conical reflector barrel plus lens of the photodetector, the reflective coating coated inside the conical reflector barrel is used to reflect the signal light, and the lens is used to focus and bundle the signal light, which can effectively shield the interference of bypass light and environmental noise light in the calibration process, greatly reduce the hardware and calibration light environment requirements, and can be used for on-site automatic calibration. The calibration system uses an XY scanning mechanism to scan the light emitting diode signal array of the camera frame rate exposure time tester one by one. The XY scanning mechanism includes a horizontal X-axis moving arm, a vertical Y-axis moving arm, a rotating mechanism, and a motor group. The rotating mechanism is used for fine-tuning the photodetector and measuring the isotropy of the optical parameter. The motor is controlled by a motor controller, and the motor controller communicates and controls with the computer through a data bus. A "Z"-shaped scanning scheme is used to calibrate the camera frame rate exposure time tester. A coordinate system is established with the center of the signal light array of the camera frame rate exposure time tester as the coordinate origin. Starting from the signal light No. 1 in the upper left corner, scanning measurements are performed one by one in a "Z" shape. This scheme has the characteristics of anti-interference, easy on-site use, and automatic calibration.

[0081] Embodiment 2:

[0082] Based on the above-mentioned camera frame rate exposure time tester calibration system, this embodiment further proposes a camera frame rate exposure time tester calibration method, including the steps of:

[0083] S1. Measure and calibrate the electrical parameters of the camera frame rate exposure time tester:

[0084] The XY scanning mechanism is controlled by a computer and a stepping motor controller to perform scanning motion according to a preset path, and the photoelectric detector is detachably arranged on the rotating mechanism of the XY scanning mechanism;

[0085] The LED lamp beads of the light emitting diode signal emission array of the camera frame rate exposure time tester under inspection are scanned and measured one by one by a photoelectric detector, and the light signals of the LED lamp beads of the light emitting diode signal emission array are converted into electrical signals and input into an electrical parameter analysis device, and the electrical parameter analysis device measures the electrical parameters of the output signal of the photoelectric detector and outputs the electrical parameter measurement data to a computer;

[0086] The electrical parameter measurement data output by the electrical parameter analysis device is collected and recorded by a computer, the indication error or relative error of the electrical parameter of the camera frame rate exposure time tester is calculated, and the camera frame rate exposure time tester is calibrated so that the display value of the electrical parameter is consistent with the reference value;

[0087] S2. Measure and calibrate the optical parameters of the camera frame rate exposure time tester:

[0088] The XY scanning mechanism is controlled by a computer and a stepping motor controller to perform scanning motion according to a preset path, and the optical collimation coupler is detachably arranged on the rotating mechanism of the XY scanning mechanism;

[0089] The LED lamp beads of the light emitting diode signal emission array of the camera frame rate exposure time tester under inspection are scanned and measured one by one through an optical collimation coupler, and the optical signals of the LED lamp beads of the light emitting diode signal emission array are collimated and coupled to the spectrometer, and the spectrometer measures the optical parameters of the optical signals of the LED lamp beads and outputs the optical parameter measurement data to a computer;

[0090] The optical parameter measurement data output by the spectrometer is collected and recorded by a computer, the indication error or relative error of the optical parameter of the camera frame rate exposure time tester is calculated, and the camera frame rate exposure time tester is calibrated so that the displayed value of its optical parameter is consistent with the reference value.

[0091] Specifically, the computer determines the difference between a certain optical parameter or electrical parameter of the camera frame rate exposure time tester and a reference value according to the indication error or relative error of the camera frame rate exposure time tester, controls the camera frame rate exposure time tester to adjust its internal crystal oscillator frequency through the computer according to the indication error or relative error, and calls the control software to modify the display value of the camera frame rate exposure time tester so that the display value of the camera frame rate exposure time tester is consistent with the reference value, thereby achieving the purpose of correcting the display value error of the camera frame rate exposure time tester.

[0092] The indication error is calculated by the following formula:

[0093] Δ=y x-y0,

[0094] Where: Δ is the indication error of a certain parameter, y x is the set value or nominal value of the frame rate exposure time test of the camera under test; y0 is the measured value or reference value of this calibration system.

[0095] The relative error is calculated as follows, where δ is the relative error:

[0096]

[0097] For the crystal oscillator type calibrated with absolute error, the computer uses the calculated indication error to calibrate the crystal oscillator of the camera frame rate exposure time tester; for the crystal oscillator type calibrated with relative error or percentage, the computer uses the calculated relative error to calibrate the crystal oscillator of the camera frame rate exposure time tester.

[0098] Specifically, the electrical parameters of the camera frame rate exposure time tester are measured and calibrated, and the electrical parameters of the camera frame rate exposure time tester include: frame frequency, response time, exposure time, shutter time, phase, time interval, duty cycle, etc.

[0099] Specifically, the optical parameters of the camera frame rate exposure time tester are measured and calibrated, and the optical parameters of the camera frame rate exposure time tester include central wavelength, spectral width, optical parameter isotropy and other optical parameters.

[0100] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A camera frame rate exposure time tester calibration system, characterized in that: It includes a photoelectric detector, an XY scanning mechanism, a stepper motor controller, an electrical parameter analysis device, a frequency meter, a computer, an atomic frequency standard device, an optical collimation coupler, and a spectrum analyzer. The photoelectric detector and the optical collimation coupler are connected to the XY scanning mechanism, the electrical parameter analysis device is connected to the photoelectric detector, the atomic frequency standard device, and the computer, and the spectrum analyzer is connected to the optical collimation coupler and the computer; The photoelectric detector is used to convert the frame rate and time optical signals output by the frame rate exposure time tester of the camera under inspection into electrical signals and input them into the electrical parameter analysis equipment; the electrical parameter analysis equipment is used to receive the output signal of the photoelectric detector, measure the electrical parameters of the output signal of the photoelectric detector, and output the electrical parameter measurement data to the computer; The optical collimation coupler is used to collimate the optical signal output by the camera frame rate exposure time tester and couple it to the spectrometer. The spectrometer is used to receive and measure the optical parameters of the optical signal output by the camera frame rate exposure time tester and output the optical parameter measurement data to the computer. The stepper motor controller is connected to the XY scanning mechanism and the computer respectively. The stepper motor controller is controlled by the computer to make the XY scanning mechanism perform scanning motion according to a preset path. The XY scanning mechanism is used to scan the light emitting diode signal emission array of the frame rate exposure time tester of the camera under test one by one using the photoelectric detector and the light collimation coupler along the predetermined moving path. The computer is used to collect and record the electrical parameter measurement data output by the electrical parameter analysis equipment and the optical parameter measurement data output by the spectrometer, calculate the measurement error of the camera frame rate exposure time tester, and correct the display value of the camera frame rate exposure time tester.

2. A camera frame rate exposure time tester calibration system according to claim 1, characterized in that: The photoelectric detector comprises a detector, a lens and a conical reflective lens barrel, wherein the lens is arranged between the light input port of the detector and the conical reflective lens barrel, the conical reflective lens barrel is fixed on the outer shell of the detector, the conical reflective lens barrel comprises a first end hole and a second end hole, the diameter of the first end hole is smaller than the diameter of the second end hole, and the second end hole of the conical reflective lens barrel surrounds the light input port of the detector.

3. A camera frame rate exposure time tester calibration system according to claim 2, characterized in that: The interior of the conical reflective lens barrel is coated with a light reflective coating for reflecting the output light of the camera frame rate exposure time tester, and the exterior of the conical reflective lens barrel is coated with a black light-proof coating.

4. A camera frame rate exposure time tester calibration system according to claim 2, characterized in that: The XY scanning mechanism comprises a horizontal X-axis moving arm, a vertical Y-axis moving arm, a rotating mechanism and a motor group. The horizontal X-axis moving arm is vertically connected to the vertical Y-axis moving arm, the rotating mechanism is vertically connected to the vertical Y-axis moving arm, and the photodetector and the optical collimation coupler are detachably arranged on the rotating mechanism.

5. A camera frame rate exposure time tester calibration system according to claim 4, characterized in that: The motor group includes an X-axis motor, a Y-axis motor and a rotary motor. The X-axis motor is used to control the vertical Y-axis movable arm to move on the horizontal X-axis movable arm, the Y-axis motor is used to control the rotary mechanism to move on the vertical Y-axis movable arm, and the rotary motor is used to control the rotary mechanism to rotate.

6. A camera frame rate exposure time tester calibration system according to claim 4, characterized in that: The electrical parameter analysis device is an oscilloscope or a frequency meter.

7. A camera frame rate exposure time tester calibration system according to claim 6, characterized in that: The atomic frequency standard is used to lock the time base of an oscilloscope and a frequency meter.

8. A camera frame rate exposure time tester calibration method, implemented based on a camera frame rate exposure time tester calibration system according to any one of claims 1 to 7, characterized in that: Includes steps: S1. Measure and calibrate the electrical parameters of the camera frame rate exposure time tester: The XY scanning mechanism is controlled by a computer and a stepping motor controller to perform scanning motion according to a preset path, and the photoelectric detector is detachably arranged on the rotating mechanism of the XY scanning mechanism; The LED lamp beads of the light emitting diode signal emission array of the camera frame rate exposure time tester under inspection are scanned and measured one by one by a photoelectric detector, and the light signals of the LED lamp beads of the light emitting diode signal emission array are converted into electrical signals and input into an electrical parameter analysis device, and the electrical parameter analysis device measures the electrical parameters of the output signal of the photoelectric detector and outputs the electrical parameter measurement data to a computer; The electrical parameter measurement data output by the electrical parameter analysis device is collected and recorded by a computer, the indication error or relative error of the electrical parameter of the camera frame rate exposure time tester is calculated, and the camera frame rate exposure time tester is calibrated so that the display value of the electrical parameter is consistent with the reference value; S2. Measure and calibrate the optical parameters of the camera frame rate exposure time tester: The XY scanning mechanism is controlled by a computer and a stepping motor controller to perform scanning motion according to a preset path, and the optical collimation coupler is detachably arranged on the rotating mechanism of the XY scanning mechanism; The LED lamp beads of the light emitting diode signal emission array of the camera frame rate exposure time tester under inspection are scanned and measured one by one through an optical collimation coupler, and the optical signals of the LED lamp beads of the light emitting diode signal emission array are collimated and coupled to the spectrometer, and the spectrometer measures the optical parameters of the optical signals of the LED lamp beads and outputs the optical parameter measurement data to a computer; The optical parameter measurement data output by the spectrometer is collected and recorded by a computer, the indication error or relative error of the optical parameter of the camera frame rate exposure time tester is calculated, and the camera frame rate exposure time tester is calibrated so that the displayed value of its optical parameter is consistent with the reference value.

9. A camera frame rate exposure time tester calibration method according to claim 8, characterized in that: The computer determines the difference between a certain optical parameter or electrical parameter of the camera frame rate exposure time tester and a reference value according to the indication error or relative error of the camera frame rate exposure time tester, controls the camera frame rate exposure time tester through the computer to adjust its internal crystal oscillator frequency according to the indication error or relative error, and calls the control software to modify the display value of the camera frame rate exposure time tester so that the display value of the camera frame rate exposure time tester is consistent with the reference value.

10. A camera frame rate exposure time tester calibration method according to claim 8, characterized in that: The electrical parameters of the camera frame rate exposure time tester include: frame frequency, response time, exposure time, shutter time, phase, time interval, and duty cycle. The optical parameters of the camera frame rate exposure time tester include: central wavelength, spectral width, and optical parameter isotropy.

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