Cathode segment-based image intensifier local exposure time and delay calibration system and calibration method

Abstract

The application discloses a cathode partition-based image intensifier local exposure time and delay calibration system and method, solves the problem that the shortest exposure time calibration of the cathode whole surface of the gated image intensifier cannot distinguish the influence of the gate pulse width and the propagation time, causes the exposure time to be unable to be accurately measured and further introduces the timing error, and the application comprises a femtosecond pulse laser, a half-transmission half-reflection mirror, a gate power module, a CMOS camera, a high-voltage power supply, a signal source, a high-bandwidth oscilloscope, a photoelectric detector and an upper computer; the influence of the gate electric pulse propagation time and the gate electric pulse half-height width on the optical exposure time is decoupled and separated, and is respectively attributed to the sub-area relative delay and the sub-area local exposure time, the time resolution capability of the gated image intensifier can be improved, and the time measurement precision can be improved when the same half-height width of the gate electric pulse is selected for the same gated image intensifier.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of optical measurement and imaging system and method, and particularly relates to a local exposure time and delay calibration system and method for an image intensifier based on cathode partition. BACKGROUND

[0002] A gated image intensifier is a key ultrafast optical imaging device, which is widely used in the observation of various high-speed transient processes. Its core working mechanism is to realize the response to photons within a specific time window through the control of a fast-gated cathode, so that the device can complete image acquisition within picoseconds to nanoseconds, and then exposure time calibration is performed.

[0003] The traditional exposure time calibration method mainly calibrates the entire cathode uniformly, i.e., the "global exposure time" calibration method. However, in actual applications, due to the limited propagation speed of the gating pulse in the cathode (which is one-third of the speed of light), there is a time delay in the signal propagation from the input end of the gating pulse to each part of the entire cathode, especially in large-aperture cathodes, which may reach hundreds of picoseconds. Specifically, the opening or closing time of the center and the edge of the cathode is not consistent, causing "iris delay". This effect will cause obvious time-domain errors in the current widely used high-time-resolution imaging system.

[0004] Taking a time-resolved single-photon imaging system as an example, different positions of single-photon events should originally be time-stamped with their true flight times, but if a uniform global exposure time is used as a reference benchmark for all positions, the opening time difference caused by the iris effect will introduce systematic measurement errors. In sub-nanosecond measurement tasks, the influence of this error cannot be ignored.

[0005] In addition, when applied to multi-frame time-resolved imaging of laser-driven plasmas, multiple sub-images are mapped to different regions of the cathode through beam splitting, and multiple dynamic frames can be captured in a single exposure. However, if the opening / closing difference of each sub-image region in the time dimension is ignored, the measurement accuracy will also be limited. SUMMARY

[0006] The purpose of the present application is to solve the problem that the shortest exposure time calibration of the entire cathode of a gated image intensifier cannot distinguish the influence of the gating pulse width and the propagation time, resulting in inaccurate measurement of the exposure time and introducing timing errors, and to provide a local exposure time and delay calibration system and method for an image intensifier based on cathode partition.

[0007] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0008] The application discloses a cathode partition-based local exposure time and delay calibration system of an image intensifier, and has the characteristics that the system comprises a femtosecond pulse laser, a half-transmitting and half-reflecting mirror, a gate power module, a CMOS camera, a high-voltage power supply, a signal source, a high-bandwidth oscilloscope, a photodetector and an upper computer.

[0009] The femtosecond pulse laser emits laser pulses, and the laser pulses are divided into a transmitting light beam and a reflecting light beam through the half-transmitting and half-reflecting mirror; the photodetector is arranged on an optical path of the reflecting light beam; and a cathode of a gate image intensifier to be calibrated is arranged on an optical path of the transmitting light beam.

[0010] The photodetector is used for converting the reflecting light beam into a time reference electrical signal and outputting the time reference electrical signal to a first input end of the high-bandwidth oscilloscope.

[0011] The signal source is connected with the femtosecond pulse laser through an input end, and is connected with the gate power module and the CMOS camera through output ends; the femtosecond pulse laser outputs a trigger signal a when outputting laser pulses; the trigger signal a triggers the signal source to generate a trigger signal b for triggering the gate power module and a trigger signal c for triggering the CMOS camera; the gate power module generates a gate electric pulse according to the trigger signal b and outputs the gate electric pulse to the cathode of the gate image intensifier to generate a cathode pulse.

[0012] The lens of the CMOS camera is arranged opposite to an output surface of a fluorescent screen of the gate image intensifier, and the output end of the CMOS camera is connected with the upper computer; the trigger signal c triggers the CMOS camera to collect an image of the output surface of the fluorescent screen of the gate image intensifier and transmit the image to the upper computer.

[0013] The high-voltage power supply is connected with the gate image intensifier and is used for supplying power to the gate image intensifier.

[0014] The second input end of the high-bandwidth oscilloscope is connected with the cathode output end of the gate image intensifier, and is used for receiving the cathode pulse of the gate image intensifier and calculating a time difference with the time reference electrical signal.

[0015] Further, a light homogenizer is arranged between the half-transmitting and half-reflecting mirror and the cathode of the gate image intensifier, and the light homogenizer is used for uniformly diffusing the transmitting light beam.

[0016] Further, the gate electric pulse output by the gate power module is a zero-order Gaussian negative pulse with a full width at half maximum less than 1 ns and a voltage greater than -200 V.

[0017] Further, the bandwidth of the high-bandwidth oscilloscope is greater than or equal to 8 GHz, and the sampling rate is greater than or equal to 100 GS / s.

[0018] The application discloses a cathode partition-based image intensifier local exposure time and delay calibration method.

[0019] Step 1, the cathode of the gated image intensifier to be calibrated is divided into a plurality of sub-regions; the total exposure time of the cathode of the gated image intensifier is estimated, an exposure step is set, and the total adjustment times are calculated;

[0020] Step 2, a femtosecond pulse laser is started to emit a laser pulse, and trigger signals a, b and c are output simultaneously; the laser pulse is divided into a transmission beam and a reflection beam through a half-transmission half-reflection mirror, and the reflection beam is incident on a photodetector to be converted into a time reference electrical signal; the output delay time of the trigger signal b is adjusted through a signal source, so that the gated electrical pulse and the transmission beam reach the cathode of the gated image intensifier at the same time, and the gated electrical pulse triggers the cathode of the gated image intensifier to generate a cathode pulse;

[0021] Step 3, an exposure image is output through a fluorescent screen of the gated image intensifier, and the exposure image is collected by a CMOS camera triggered by the trigger signal c; and the time difference between the cathode pulse and the time reference electrical signal is obtained through a high-bandwidth oscilloscope;

[0022] Step 4, the output delay time of the trigger signal b is adjusted according to the exposure step, and step 3 is returned until the total adjustment times are reached, so that a sequence of exposure images covering the cathode of the gated image intensifier as a whole is obtained;

[0023] Step 5, the static background of each image in the sequence of exposure images is removed, and the sum of pixel gray scales of each sub-region is calculated respectively; a curve of the sum of pixel gray scales of each sub-region changing with the delay time is constructed, and is fitted into a Gaussian function; the center time of the Gaussian function is taken as the delay time of the sub-region, and the full width at half maximum of the Gaussian function is taken as the local exposure time of the sub-region;

[0024] Step 6, a two-dimensional distribution diagram of the local exposure time of all sub-regions and the delay time of the sub-regions in each sub-region of the cathode of the gated image intensifier is drawn, so that the time-domain response parameter distribution of the cathode of the gated image intensifier is obtained, and the local exposure time and the delay calibration of the gated image intensifier are completed.

[0025] Further, step 1 is specifically as follows:

[0026] According to the mapping relationship between the side of the cathode of the gated image intensifier to be calibrated receiving the transmission beam and the equivalent pixels of the CMOS camera, the side of the cathode of the gated image intensifier receiving the transmission beam is divided into N rectangular sub-regions, and the sub-region number is i, i=1, …, N.

[0027] Further, the trigger signal b is delayed from the trigger signal c by 0-100 seconds.

[0028] Further, step 5 is specifically:

[0029] Step 5.1, in the exposure image sequence of the gated image intensifier cathode, the time t when the gating electric pulse reaches the gated image intensifier cathode is used to shoot the sub-region i of the image, and the corresponding background is recorded as , wherein, , wherein, represents the horizontal and vertical coordinate positions of the pixels in the sub-region i;

[0030] Step 5.2, the static background of each image in the exposure image sequence is removed, and the sum of the pixel gray scales of each sub-region i is calculated , and the calculation formula is:

[0031] ;

[0032] In the formula, is the pixel set corresponding to the sub-region i;

[0033] Step 5.3, the curve of the sum of the pixel gray scales of each sub-region changing with the delay time is constructed, wherein the delay time is the time t when the gating electric pulse reaches the gated image intensifier cathode, then the curve is subjected to Gaussian fitting to obtain a Gaussian function, and the expression is:

[0034] ;

[0035] In the formula, represents the highest amplitude of the Gaussian function of the sub-region i, represents the center time of the Gaussian function of the sub-region i, represents the standard deviation of the Gaussian function of the sub-region i;

[0036] Step 5.4, the center time of the Gaussian function of the sub-region i is taken as the delay time of the sub-region , and the expression is:

[0037] ;

[0038] Step 5.5, the local exposure time of the sub-region i is derived from the full width at half maximum (FWHM) of the Gaussian function i , that is:

[0039] .

[0040] The beneficial effects of the present application are:

[0041] (1) The local exposure time and delay calibration system and calibration method of the image intensifier based on cathode partitioning provided by the present invention regards the photocathode of the gated image intensifier as an equivalent pixel or equivalent frame combination surface composed of multiple sub-regions, breaking the traditional limitation of calibrating the cathode imaging area of ​​the gated image intensifier as a single frame globally; through partitioning, a shorter optical exposure time can be obtained on gated image intensifiers with larger cathode imaging size (such as 25mm or 40mm aperture), realizing imaging capability with larger area and higher spatiotemporal resolution, further enhancing the adaptability and scalability of large-aperture gated image intensifiers.

[0042] (2) The local exposure time and delay calibration system and calibration method of the image intensifier based on cathode partitioning provided by the present invention decouples and separates the influence of gated electrical pulse propagation time and gated electrical pulse half-width on optical exposure time, attributes the influence of gated electrical pulse propagation time to the relative delay of sub-region, and attributes the influence of gated electrical pulse half-width to the local exposure time of sub-region. This can improve the time resolution of the gated image intensifier. For the same gated image intensifier, when using the same gated electrical pulse half-width for gating, the global exposure time measured by the traditional calibration method is 332ps, while the local exposure time can be 195±22ps after using the present invention, which can significantly improve the time measurement accuracy.

[0043] (3) The local exposure time and delay calibration system and calibration method of the image intensifier based on cathode partitioning provided by the present invention can eliminate the single-photon time error introduced by the iris effect of the gated image intensifier in different sub-regions in single-photon imaging scenarios. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of an embodiment of the local exposure time and delay calibration system for an image intensifier based on cathode partitioning provided by the present invention.

[0045] Figure 2 The exposure image sequence obtained at different delay times in step 3 of the embodiment of the image intensifier local exposure time and delay calibration method based on cathode partitioning provided by the present invention;

[0046] Figure 3 In an embodiment of the image intensifier local exposure time and delay calibration method based on cathode partitioning provided by the present invention, a two-dimensional distribution map of the local exposure time and delay time of a 64×64 pixel sub-region on the cathode imaging region is shown.

[0047] Among them, (a) is a two-dimensional distribution map of the local exposure time of the 64×64 pixel sub-region on the cathode imaging region, and (b) is a two-dimensional distribution map of the delay time of the 64×64 pixel sub-region on the cathode imaging region.

[0048] Reference signs:

[0049] 1-femtosecond pulse laser; 2-semi-transparent semi-reflective mirror; 3-homogenizer; 4-gated image intensifier; 5-gated power module; 6-CMOS camera; 7-high-voltage power supply; 8-signal source; 9-high-bandwidth oscilloscope; 10-photoelectric detector; 11-upper computer. DETAILED DESCRIPTION

[0050] The technical solutions of the present application will be described clearly and completely below in combination with embodiments. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0051] The present embodiment provides a cathode partition-based local exposure time and delay calibration system for an image intensifier, as shown in the figure, comprising a femtosecond pulse laser 1, a semi-transparent semi-reflective mirror 2, a homogenizer 3, a gated power module 5, a CMOS camera 6, a high-voltage power supply 7, a signal source 8, a high-bandwidth oscilloscope 9, a photoelectric detector 10, and an upper computer 11. Figure 1 As shown in the figure, the femtosecond pulse laser 1, the semi-transparent semi-reflective mirror 2, the homogenizer 3, the cathode of the gated image intensifier 4 to be calibrated, the gated power module 5, the CMOS camera 6, the high-voltage power supply 7, the signal source 8, the high-bandwidth oscilloscope 9, the photoelectric detector 10, and the upper computer 11 are sequentially connected in series.

[0052] The femtosecond pulse laser 1 (typical parameter pulse width 220 femtoseconds) emits a laser pulse, which is divided into a transmitted beam and a reflected beam by the semi-transparent semi-reflective mirror 2. The homogenizer 3 and the cathode of the gated image intensifier 4 to be calibrated are sequentially arranged on the optical path of the transmitted beam, and the transmitted beam passes through the homogenizer 3 and is incident on the cathode of the gated image intensifier 4. The photoelectric detector 10 is arranged on the optical path of the reflected beam, and the reflected beam is incident on the photoelectric detector 10 to convert the reflected beam into a time reference electrical signal.

[0053] The input end of the signal source 8 is connected to the signal output end of the femtosecond pulse laser 1, and the output end thereof is connected to the gated power module 5 and the CMOS camera 6, respectively. The femtosecond pulse laser 1 outputs a laser pulse and simultaneously outputs a trigger signal a synchronized with the laser pulse. The trigger signal a triggers the signal source 8 to generate a trigger signal b triggering the gated power module 5 and a trigger signal c triggering the CMOS camera 6.

[0054] The output end of the gated power module 5 is connected to the cathode of the gated image intensifier 4. The trigger signal b triggers the gated power module 5 to generate a gated pulse, which is input to the cathode of the gated image intensifier 4 to generate a cathode pulse. The gated pulse is a zero-order Gaussian negative pulse with a full-width-at-half-maximum numerical value of 170 ps and a voltage of -270 V.

[0055] The delay time of the trigger signal b output by the signal source is adjusted in this embodiment, so that the time when the gate pulse reaches the cathode of the gated image intensifier 4 can be accurately adjusted, and the adjustment step precision can reach 10 ps. When the gate electric pulse and the laser pulse reach the cathode of the gated image intensifier 4 at the same time, an exposed image can be obtained.

[0056] The lens of the CMOS camera 6 is arranged relative to the fluorescent screen output surface of the gated image intensifier 4, and the output end is connected to the host computer 11. The trigger signal c triggers the CMOS camera 6 to collect the image of the fluorescent screen output surface of the gated image intensifier 4 and transmit it to the host computer 11.

[0057] The high-voltage power supply 7 is connected to the gated image intensifier 4, and is used to provide a static working voltage for the microchannel plate (MCP) and the fluorescent screen of the gated image intensifier 4.

[0058] The photodetector 10 is connected to the first input end of the high-bandwidth oscilloscope 9, and the cathode output end of the gated image intensifier 4 is connected to the second input end of the high-bandwidth oscilloscope 9. The high-bandwidth oscilloscope 9 is used to receive the cathode pulse of the gated image intensifier 4 and calculate the time difference between the high-bandwidth oscilloscope 9 and the time reference electrical signal, so as to accurately measure the arrival time of the gate pulse. At the same time, the reflected light beam of the laser pulse passing through the half-mirror 2 is incident on the photodetector 10 to obtain a time reference electrical signal for triggering the high-bandwidth oscilloscope 9. Comparing the cathode pulse of the gated image intensifier 4 with the time reference electrical signal can exclude the trigger jitter of the electronic system and accurately measure the arrival time of the gate electric pulse. The bandwidth of the high-bandwidth oscilloscope 9 is ≥8 GHz, and the sampling rate is ≥100 GS / s.

[0059] The embodiment also provides a cathode partition-based local exposure time and delay calibration method for an image intensifier, which is used for calibrating a gated image intensifier with an S25 cathode. The diameter of the gated image intensifier 4 is 18 mm, and a microstructure metal lower electrode layer is integrated in the cathode, which can improve the propagation performance of the gate pulse. Unlike the traditional gated image intensifier, the device can monitor the propagation arrival time of the gate pulse in real time.

[0060] The cathode partition-based local exposure time and delay calibration method is based on the cathode partition-based local exposure time and delay calibration system, and includes the following steps.

[0061] Step 1: According to the mapping relationship between the side of the cathode of the gated image intensifier 4 receiving the transmitted light beam and the equivalent pixels of the CMOS camera 6, the side of the cathode of the gated image intensifier 4 receiving the transmitted light beam is divided into N rectangular sub-regions, such as 16×16, 32×32, 64×64, etc., and the sub-regions are numbered as i, i=1, …, N.

[0062] The total exposure time of the cathode of the gated image intensifier 4 is estimated, and the exposure step is set, and the total adjustment times are calculated.

[0063] Step 2, turn on the femtosecond pulse laser 1 to output laser pulses with a pulse width of 220 femtoseconds, and output trigger signals a, trigger signal b and trigger signal c at the same time. The output delay time of the trigger signal b is adjusted through the signal source 8, the gated electric pulse generated by the gated power supply module 5 is a zero-order Gaussian negative pulse with a full width at half maximum of 170 ps and a voltage of-270 V; the laser pulse is divided into a transmitted beam and a reflected beam by the half-transmission half-reflection mirror 2, the reflected beam is incident on the photodetector 10 to be converted into a time reference electrical signal, the gated electric pulse and the transmitted beam reach the cathode of the gated image intensifier 4 at the same time, and the gated electric pulse triggers the cathode of the gated image intensifier 4 to generate a cathode pulse.

[0064] Step 3, output the exposure image through the fluorescent screen of the gated image intensifier 4, and trigger the CMOS camera 6 to collect the exposure image through the trigger signal c; at the same time, the time difference between the cathode pulse and the time reference electrical signal is obtained through the high-bandwidth oscilloscope 9.

[0065] Step 4, adjust the output delay time of the trigger signal b step by step according to the exposure step, return to step 3, until the total adjustment times are reached, and obtain the exposure image sequence covering the cathode of the gated image intensifier 4 as a whole, as shown in Figure 2 , the exposure image sequence obtained at different delay times, wherein the delay times of the multiple images are 0 ps, 45 ps, 86 ps, 120 ps, 172 ps, 200 ps, 235 ps, 258 ps, 298 ps, 332 ps, 395 ps and 458 ps in turn.

[0066] Step 5, remove the static background of each image in the exposure image sequence, and calculate the sum of the pixel gray scales of each sub-region respectively; construct the curve of the sum of the pixel gray scales of each sub-region changing with the delay time, and fit it into a Gaussian function, take the center time of the Gaussian function as the delay time of the sub-region, and take the full width at half maximum of the Gaussian function as the local exposure time of the sub-region. Specifically,

[0067] Step 5.1, in the exposure image sequence of the cathode of the gated image intensifier 4, the sub-region i of the image taken at the moment t when the gated electric pulse reaches the cathode of the gated image intensifier 4 is , and the corresponding background is , wherein, represents the horizontal and vertical coordinate positions of the pixels in the sub-region i.

[0068] Step 5.2, remove the static background of each image in the exposure image sequence, and calculate the sum of the pixel gray scales of each sub-region i , and the calculation formula is:

[0069] ;

[0070] wherein, is the pixel set corresponding to the sub-region i;

[0071] Step 5.3, construct the curve of the sum of the pixel gray scale of each sub-region versus the delay time, wherein the delay time is the time t at which the gating electric pulse reaches the cathode of the gated image intensifier 4, then conduct Gaussian fitting on the curve to obtain a Gaussian function, the expression of which is:

[0072] ;

[0073] wherein, represents the highest amplitude of the Gaussian function of the sub-region i, represents the center time of the Gaussian function of the sub-region i, represents the standard deviation of the Gaussian function of the sub-region i;

[0074] Step 5.4, N sub-regions are regarded as N independent frames or independent pixels, when the sub-region division is small enough, the influence of the propagation of the gating electric pulse in the sub-region on the overall optical exposure time of the sub-region will be negligible, and the local exposure time of the sub-region will be determined only by the half-height width of the gating electric pulse. For the entire cathode, the propagation time of the gating electric pulse on the cathode of the gated image intensifier 4 on the overall optical exposure time of the cathode will be converted into the exposure delay time between the sub-regions , and then the center time of the Gaussian function of the sub-region i is taken as the delay time of the sub-region , the expression of which is:

[0075] ;

[0076] Step 5.5, the local exposure time of the sub-region i is derived from the full width at half maximum FWHM of the Gaussian function i , that is:

[0077] .

[0078] Step 6, draw the two-dimensional distribution diagram of the local exposure time of all sub-regions and the delay time of the sub-regions on the cathode of the gated image intensifier 4, to obtain the time-domain response parameter distribution of the cathode of the gated image intensifier 4, and complete the local exposure time and delay calibration of the gated image intensifier, such as Figure 3As shown, the local exposure time of a 64*64 pixel sub-region and the two-dimensional distribution of the delay time of the sub-region on the cathode imaging area are shown, the horizontal coordinate represents the X-axis pixel position, and the vertical coordinate represents the Y-axis pixel position; wherein (a) is the two-dimensional distribution of the local exposure time of the 64*64 pixel sub-region on the cathode imaging area, and (b) is the two-dimensional distribution of the delay time of the 64*64 pixel sub-region on the cathode imaging area.

[0079] According to Figure 3 As can be seen from (a) and (b), the calibration method of the present embodiment can be used in subsequent time-of-flight measurement, the time response characteristics of the corresponding sub-region can be retrieved according to the position of the single photon event, and the hundred picosecond level timestamp correction can be realized. In the superfast sub-region imaging, the above calibration results can also be used to correct the exposure time and delay time of different sub-regions of the same cathode, and the superfast imaging time measurement accuracy can be greatly improved.

[0080] The above is only a specific embodiment of the present application, and the effect of the related comparative example is compared, but the protection scope of the present application is not limited thereto, any change or replacement within the technical scope disclosed in the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A cathode zoning based image intensifier local exposure time and delay calibration system, characterized by: The system comprises a femtosecond pulse laser (1), a half-transmission half-reflection mirror (2), a gating power module (5), a CMOS camera (6), a high-voltage power supply (7), a signal source (8), a high-bandwidth oscilloscope (9), a photodetector (10) and a host computer (11). The femtosecond pulse laser (1) emits laser pulses, which are divided into a transmission beam and a reflection beam by the half-transmission half-reflection mirror (2), and the photodetector (10) is arranged on the light path of the reflection beam, and the cathode of the gating image intensifier (4) to be calibrated is arranged on the light path of the transmission beam. The photodetector (10) is used to convert the reflection beam into a time reference electrical signal and output to the first input end of the high-bandwidth oscilloscope (9). The input end of the signal source (8) is connected to the signal output end of the femtosecond pulse laser (1), the output end of the signal source (8) is connected to the gating power module (5) and the CMOS camera (6) respectively, the femtosecond pulse laser (1) outputs laser pulses and trigger signals a, the trigger signals a trigger the signal source (8) to generate trigger signals b and c to trigger the gating power module (5) and the CMOS camera (6) respectively; the output end of the gating power module (5) is connected to the cathode of the gating image intensifier (4), the gating power module (5) generates a gating electrical pulse according to the trigger signal b and outputs it to the cathode of the gating image intensifier (4) to generate a cathode pulse. The lens of the CMOS camera (6) is arranged relative to the output surface of the fluorescent screen of the gating image intensifier (4), and the output end is connected to the host computer (11), the trigger signal c triggers the CMOS camera (6) to collect the image of the output surface of the fluorescent screen of the gating image intensifier (4) and transmit it to the host computer (11). The high-voltage power supply (7) is connected to the gating image intensifier (4) to supply power to the gating image intensifier (4). The second input end of the high-bandwidth oscilloscope (9) is connected to the cathode output end of the gating image intensifier (4) to receive the cathode pulse of the gating image intensifier (4) and calculate the time difference with the time reference electrical signal.

2. The cathode zoning based image intensifier local exposure time and delay calibration system of claim 1, wherein: The homogenizing mirror (3) is arranged between the half-transmission half-reflection mirror (2) and the cathode of the gating image intensifier (4), and the homogenizing mirror (3) is used for uniformly diffusing the transmission beam.

3. The cathode zoning based image intensifier local exposure time and delay calibration system of claim 1, wherein: The gating electrical pulse output by the gating power module (5) is a zero-order Gaussian negative pulse with a half-peak full-width numerical value less than 1 ns and a voltage greater than -200 V.

4. The cathode zoning based image intensifier local exposure time and delay calibration system of claim 1, wherein: The bandwidth of the high-bandwidth oscilloscope (9) is ≥8GHz, and the sampling rate is ≥100GS / s.

5. A method for local exposure time and delay calibration of a cathodically zoned image intensifier, characterized by, The system for local exposure time and delay calibration of the gating image intensifier based on cathode partitioning comprises the following steps: Step 1: divide the cathode of the gating image intensifier (4) to be calibrated into multiple sub-regions; estimate the total exposure time of the cathode of the gating image intensifier (4), set the exposure step, and calculate the total adjustment times. Step 2, turn on the femtosecond pulse laser (1) to emit laser pulses, and output trigger signals a, b and c from the trigger signal source (8), the laser pulses are divided into transmitted beams and reflected beams by the half-transmission half-reflection mirror (2), and the reflected beams are incident into the photodetector (10) to be converted into time reference electrical signals; the output delay time of the trigger signal b is adjusted by the signal source (8) to make the gate electrical pulse and the transmitted beam reach the cathode of the gated image intensifier (4) at the same time, and the gate electrical pulse triggers the cathode of the gated image intensifier (4) to generate a cathode pulse; Step 3, output the exposure image through the fluorescent screen of the gated image intensifier (4), and trigger the CMOS camera (6) to collect the exposure image through the trigger signal c; at the same time, the time difference between the cathode pulse and the time reference electrical signal is obtained through the high-bandwidth oscilloscope (9); Step 4, adjust the output delay time of the trigger signal b according to the exposure step, return to step 3 until the total adjustment times are reached, and obtain the exposure image sequence covering the cathode of the gated image intensifier (4) as a whole; Step 5, remove the static background of each image in the exposure image sequence, and calculate the sum of pixel gray scales of each sub-region respectively; construct the curve of the sum of pixel gray scales of each sub-region changing with the delay time, and fit it into a Gaussian function, take the center time of the Gaussian function as the delay time of the sub-region, and take the full width at half maximum of the Gaussian function as the local exposure time of the sub-region; Step 6, draw the two-dimensional distribution diagram of the local exposure time of all sub-regions and the delay time of the sub-regions in each sub-region of the cathode of the gated image intensifier (4), obtain the time-domain response parameter distribution of the cathode of the gated image intensifier (4), and complete the calibration of the local exposure time and the delay of the gated image intensifier.

6. The image intensifier local exposure time and delay calibration method based on cathode partitioning according to claim 5, characterized in that, Step 1 is specifically: According to the mapping relationship between the side of the cathode of the gated image intensifier (4) receiving the transmitted light beam and the equivalent pixels of the CMOS camera (6), the side of the cathode of the gated image intensifier (4) receiving the transmitted light beam is divided into N rectangular sub-regions, and the sub-regions are numbered as i , i =1, …, N .

7. The image intensifier local exposure time and delay calibration method based on cathode partitioning according to claim 5, characterized in that, The delay time of the trigger signal b relative to the trigger signal c is 0-100 ns.

8. The image intensifier local exposure time and delay calibration method based on cathode partitioning according to claim 6, characterized in that, Step 5 is specifically: Step 5.

1. In the sequence of exposure images of the cathode of the gated image intensifier (4), the time of arrival of the gating pulses to the cathode of the gated image intensifier (4) t sub-areas of the image i are , the corresponding background is denoted by wherein denote the horizontal and vertical coordinate positions of a pixel in the sub-area i ​ Step 5.2, remove the static background of each image in the exposure image sequence, and calculate the sum of the pixel gray scale of each sub-region i The calculation formula is:​ ； In the formula, sub-regions i corresponding pixel set; Step 5.3, constructing the curve of the sum of pixel gray levels of each sub-region versus delay time, wherein the delay time is the time when the gating electric pulse reaches the cathode of the gated image intensifier (4) t Then, the curve is Gaussian fitted to obtain a Gaussian function, which is expressed as: ； wherein representing a sub-region i the maximum amplitude of the Gaussian function, representing a sub-region i the center time of the Gaussian function, representing a sub-region i the standard deviation of the Gaussian function; Step 5.4, sub-region i the center time of the Gaussian function as the delay time of the sub-region , which is expressed as: ； Step 5.5, sub-area i Local exposure time of Full width at half maximum of the Gaussian function FWHM i Derivation, i.e.: 。

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