Disclosure of Invention
The invention aims to solve the primary technical problem of providing a rapid calculation method for pulse energy measurement, which is suitable for a thermopile detector to carry out pulse energy measurement and has the advantages of high response speed and high accuracy.
Another technical problem to be solved by the present invention is to provide an apparatus for implementing the above fast calculation method.
In order to achieve the technical purpose, the invention adopts the following technical scheme:
according to a first aspect of the embodiments of the present invention, there is provided a fast calculation method for pulse energy measurement, which is used when a thermopile detector performs pulse energy measurement, and includes the following steps:
s1, measuring the light pulse by using a thermopile detector to obtain a voltage response curve;
s2, obtaining the initial value from the voltage response curveThreshold point (aT s ,V s ) Maximum point of (a)T m ,V m ) And an end threshold point: (T e ,V e ) WhereinV s 、V m 、V e respectively representing a starting threshold voltage, a maximum voltage and an ending threshold voltage,T s 、T m 、T e respectively representing a time point corresponding to the initial threshold voltage, a time point corresponding to the maximum voltage and a time point corresponding to the ending threshold voltage; the voltage response curve is according to the time pointT s 、T m 、T e The method comprises four stages in sequence: 0 toT s 、T s ~T m 、T m ~T e 、T e ~∞;
S3, according to the ratio of 0 toT s The shape of the curve corresponding to the stage is estimated to be 0 toT s Area under the phase correspondence curveS s ;
S4, calculating according to the actual sampling dataT s ~T m Area under the phase correspondence curveS m ;
S5, calculating according to the actual sampling dataT m ~T e Area under the phase correspondence curveS e ;
S6, according toT e ~∞The stage is estimated corresponding to the shape of the curveT e ~∞Area under the phase correspondence curveS t ;
S7, calculating the area under the whole curve of 0 to infinityS,S=S s +S m +S e +S t ;
S8, calculating the optical energy measured value of the incident lightE,E=a×S(ii) a Wherein,athe coefficients are corrected for energy calibrated to a standard light source.
Wherein preferably, in step S2, an initial threshold point is set (T s ,V s ) Obtaining a maximum point from the voltage response curve (T m ,V m ) And according to the maximum voltageV m Calculating an end threshold voltageV e And further determining an end threshold point (T e ,V e )。
Wherein preferably said end threshold voltageV e =0.368V m Or, the end threshold voltageV e =0.5V m 。
Preferably, in step S3, the method further comprises the step of calculating a threshold value according to the threshold valueT s ,V s ) And 1.2 times the onset threshold point (T s1 ,V s1) The following formula was used to calculate 0 toT s Area under curve over time periodS s :S s =(V s ×T s1)/0.4,
Wherein,V s is the starting threshold voltage of the voltage at which,V s1set to 1.2 times the starting threshold voltage,T s is the time point corresponding to the initial threshold voltage and is marked as the zero point of the collected data,T s1is 1.2 times the starting threshold voltage.
Preferably, in step S4, the following formula is used to calculateT s ~T m Area under curve over time periodS m :
Wherein,f(t i )for sampling point mappingThe value of the voltage is set to be,Δtfor the sampling time, the number of samples n ═ c (T m -T s )/Δt。
Preferably, in step S5, the following formula is used to calculateT m ~T e Area under curve over time periodS e :
Wherein,y(t i )for the sampling points to correspond to the voltage values,Δtfor the sampling time, the number of samples w ═ c (c)T e -T m )/Δt。
Preferably, in step S6,T e ~∞area under time period curveS t The estimation is made by the following formula:S t =V e ×τwhereinτis 1 ^ or which is the decay of the voltage value from the maximum value to the maximum value in the voltage response curveeTime of the double.
According to a second aspect of the embodiments of the present invention, there is provided a fast calculation apparatus for pulse energy measurement, for implementing the above fast calculation method for pulse energy measurement, including a control module, a storage module, a feature point calculation module, an area calculation module, and a power calculation module; wherein,
the control module is used for coordinating the work of other modules;
the characteristic point calculating module is used for obtaining an initial threshold value point from a voltage response curve measured by the thermopile detectorT s ,V s ) Maximum point of (a)T m ,V m ) And an end threshold point: (T e ,V e );
The area calculation module is used for calculating according to actual sampling dataT s ~T m AndT m ~T e area under the phase correspondence curveS m AndS e and estimating 0 toT s AndT e ~∞area under the phase correspondence curveS s AndS t and calculateS s 、S m 、S e AndS t sum of (2)S;
The power calculation module is used for calculating the area under the whole curve according to the range of 0 to infinitySCalculating the optical energy measurement value of the incident lightE;
The storage module is used for storing a voltage response curve measured by the thermopile detector and all calculation results of the characteristic point calculation module, the area calculation module and the power calculation module.
Wherein preferably, the feature point calculation module is used for setting a starting threshold point (T s ,V s ) And for obtaining a maximum point from the voltage response curve (T m ,V m ) And according to the maximum voltageV m Calculating an end threshold voltageV e And further determining an end threshold point (T e ,V e )。
Wherein preferably, the area calculating module is used for calculating the area of the object according to the starting threshold point (A)T s ,V s ) And 1.2 times the onset threshold point (T s1 ,V s1) The following formula was used to estimate 0 toT s Area under the time period corresponding curveS s :
S s =(V s ×T s1)/0.4,
Wherein,V s is the starting threshold voltage of the voltage at which,V s1set to 1.2 times the starting threshold voltage,T s is corresponding to the initial threshold voltageThe intermediate point, which is marked as the zero point of the collected data,T s1is 1.2 times the time point corresponding to the initial threshold voltage;
the area calculation module is used for calculating by using the following formulaT s ~T m Area under curve over time periodS m :
Wherein,f(t i )for the sampling points to correspond to the voltage values,Δtfor the sampling time, the number of samples n ═ c (T m -T s )/Δt;
The area calculation module is used for calculating by using the following formulaT m ~T e Area under curve over time periodS e :
Wherein,y(t i )for the sampling points to correspond to the voltage values,Δtfor the sampling time, the number of samples w ═ c (c)T e -T m )/Δt;
The area calculation module is further configured to pair through the following formulaT e ~∞Area under time period curveS t And (4) estimating:
wherein,τis 1 ^ or which is the decay of the voltage value from the maximum value to the maximum value in the voltage response curveeTime of the double.
The rapid calculation method for pulse energy measurement provided by the invention is suitable for being used when the thermopile detector is used for pulse energy measurement. Wherein the voltage measured by the thermopile detectorObtaining an onset threshold point in the response curve (T s ,V s ) Maximum point of (a)T m ,V m ) And an end threshold point: (T e ,V e ) The voltage response curve is according to the time pointT s 、T m 、T e Divided into four stages, and then calculated according to actual sampling dataT s ~T m AndT m ~T e area under the phase correspondence curveS m AndS e and estimating 0 toT s AndT e ~∞area under the phase correspondence curveS s AndS t and finally, calculating the sum of the areas under the corresponding curves of the four stages, and finally calculating the measured value of the optical energy. By the calculation method, the test speed can be improved, the change of the incident signal can be quickly measured, the energy value of the incident light can be quickly calculated, the measurement relative deviation is small, and the requirements of high precision and quick response on the detection object in practical application are met.
Detailed Description
The technical solution of the present invention is further described in detail with reference to the accompanying drawings and specific embodiments.
Aiming at the defects that the response speed is low and the detection precision is difficult to ensure when the thermopile detector carries out energy measurement, the calculating method which is efficient, fast and high in accuracy is provided. The algorithm can improve the testing speed, quickly measure the change of an incident signal, quickly calculate the energy value of the incident light, has small measurement relative deviation, and meets the requirements of high precision and quick response to a detection object in practical application.
As shown in FIG. 1, the fast calculation method for pulse energy measurement disclosed by the invention is used for pulse energy measurement of a thermopile detector, and comprises the following steps:
s1, measuring the light pulse by using a thermopile detector to obtain a voltage response curve;
s2, obtaining an initial threshold point from the voltage response curve (T s ,V s ) Maximum point of (a)T m ,V m ) And an end threshold point: (T e ,V e ) WhereinV s 、V m 、V e respectively representing a starting threshold voltage, a maximum voltage and an ending threshold voltage,T s 、T m 、T e respectively representing a time point corresponding to the initial threshold voltage, a time point corresponding to the maximum voltage and a time point corresponding to the ending threshold voltage; the voltage response curve is according to the time pointT s 、T m 、T e The method comprises four stages in sequence: 0 toT s 、T s ~T m 、T m ~T e 、T e ~∞;
S3, according to the ratio of 0 toT s The shape of the curve corresponding to the stage is estimated to be 0 toT s Stage corresponds to the lower part of the curveArea ofS s ;
S4, calculating according to the actual sampling dataT s ~T m Area under the phase correspondence curveS m ;
S5, calculating according to the actual sampling dataT m ~T e Area under the phase correspondence curveS e ;
S6, according toT e ~∞The stage is estimated corresponding to the shape of the curveT e ~∞Area under the phase correspondence curveS t ;
S7, calculating the area under the whole curve of 0 to infinityS,S=S s +S m +S e +S t ; (1)
S8, calculating the optical energy measured value of the incident lightE,E=a×S(ii) a Wherein,athe coefficients are corrected for energy calibrated to a standard light source.
In step S2, a start threshold point (S) is set to simplify the calculation in the subsequent stepsT s ,V s ) Then obtaining a maximum point from the voltage response curve (T m ,V m ) And according to the maximum voltageV m Calculating an end threshold voltageV e And further determining an end threshold point (T e ,V e ). According to different calculation modesT m ~T e The phase fitting function is processed to conclude that the end threshold voltage is set toV e =0.368V m Or, alternatively, the end threshold voltage is set toV e =0.5V m Can be rapidly obtained while ensuring the calculation precisionT e ~∞The area under the descending curve.
In step S3, based on the starting threshold point (S) ((T s ,V s ) And 1.2 times the onset threshold point (T s1 ,V s1) Estimate 0 to using equation (2)T s Area under the phase correspondence curveS s :
S s =(V s ×T s1)/0.4, (2)
Wherein,V s is the starting threshold voltage of the voltage at which,V s1set to 1.2 times the starting threshold voltage,T s is the time point corresponding to the initial threshold voltage and is marked as the zero point of the collected data,T s1is the time point corresponding to 1.2 times the initial threshold voltage.
In step S4, the following equation is used for calculationT s ~T m Area under curve over time periodS m :
Whereinf(t i )For the sampling points to correspond to the voltage values,Δtfor the sampling time, the number of samples n ═ c (T m -T s )/Δt。
In step S5, the following equation is used for calculationT m ~T e Area under curve over time periodS e :
Whereiny(t i )Is composed ofT m ~T e The sampling points correspond to the voltage values of the voltage,Δtfor the sampling time, the number of samples w ═ c (c)T e -T m )/Δt。
In step S6, the following equation pairsT e ~∞Area under time period curveS t And (4) estimating:
wherein,τis 1 ^ or which is the decay of the voltage value from the maximum value to the maximum value in the voltage response curveeTime of the double.
Specifically, a temperature difference model of the thermopile is established on the assumption that the pulse width of the detected laser pulse is far smaller than the thermal response period of the thermopile; calculating the induced electromotive force according to the Seebeck effect of the thermopile, wherein the induced electromotive force and the temperature difference are in direct proportionV t 。
Based on theoretical and actual data acquisition, as shown in FIG. 2, the voltage response curve of the thermopile rapidly and steeply rises to a maximum valueV m (the time point is recorded asT m ) Then slowly descending according to an exponential function curve, and because the tail time is very long, the end point can not be detected in limited time, and through reasonable calculation, the threshold voltage can be set to be overV e To determine a time point corresponding to the end threshold voltageT e And will end threshold point (T e ,V e ) As the end point of the recording; in addition, because of passive detection, the thermopile does not know the time starting point of detection in advanceT s At this time, by setting a fixed initial threshold voltageV s Corresponding time pointT s As recording zero point, a start threshold point: (T s ,V s ) Starting to record voltage and time data as a starting point of recording; thus, in the case where both the start zero point and the end point are not available, the time point corresponding to the start threshold voltage is setT s Time point corresponding to ending threshold voltageT e Calculating time points as segments and then calculating the curves between the start threshold point and the end threshold point, respectivelyThe area under the line and estimating the area under the curve before the start threshold point and after the end threshold point allows the power of the pulse to be quickly calculated and measured.
Since the energy value is proportional to the area of the curve, the corresponding energy value can be deduced by accurately calculating the area under the whole curve of 0 to infinity.
As shown in FIG. 2, the time points are knownT s 、T m 、T e Corresponding voltage values are respectivelyV s 、V m 、V e (ii) a In order to calculate the area under the whole curve of 0 to infinity, the method divides the voltage response curve into four stages according to time points, and sequentially comprises the following steps: 0 toT s 、T s ~T m 、T m ~T e 、T e ~∞(ii) a WhereinT s ~T m AndT m ~T e the time period can be calculated by sampling data; 0 toT s AndT e ~∞all the time periods are non-measurable time periods, but the area generated in the time period belongs to an energy response process, if the area is not counted, a large measurement error is generated, and the algorithm estimates 0 to 0T s AndT e ~∞the area in the time period is used for achieving the purpose of eliminating errors.
In other words, the area under the voltage response curve is defined byS s 、S m 、S e 、S t The four parts are formed. Wherein,T s ~T m andT m ~T e for the whole time periodV(t)Can be captured and recorded by the control system; the core of the algorithm is thatT s ~T e For the whole time periodV(t)Recording, calculating areaS m AndS e and estimating the areaS s AndS t and then calculating the sum of the four areas to obtain the area of the whole curve below 0 to infinity, and correcting the area by a certain linear coefficient with a standard light source to obtain the measured value of the optical energy.
The following describes a specific calculation procedure.
1. Estimate 0 toT s Time period curve function
To obtain 0 toT s First, a function of the rising curve is obtained.
In the rising curve of 0 toT s In the time period, the starting threshold point: (T s ,V s ) 0 ℃ to the frontT s The time period data cannot be acquired by the control system. Since the voltage response curve of the thermopile rapidly and steeply rises first, the initial threshold voltage can be setV s Set to a lower voltage (e.g.,V s taking 5 mV), 0 toT s The area under the time period curve can be estimated as a small triangular area. Two points are taken on the curve and the coefficients of the function are calculated. Using an initiation threshold point (T s ,V s ) And 1.2 times the onset threshold point (T s1 ,V s1),V s1=1.2×V s Calculating to obtain 0~T s Coefficient of linear function of time period, thereby estimating 0 toT s Area under the curve of the time segment.V s The selection of the thermopile detector should consider the detection precision of the thermopile detector, and simultaneously avoid the interference of other factors.V s The smaller the accuracy, the higher, butV s Too small may have interference factors present.
0~T s The time period curve is estimated to fit the formula:V t =k×t; (6)
wherein,tis the time of day or the like,V t is time of daytThe real-time output voltage of the voltage converter,kis a coefficient of a scaling function; the proportionality coefficient of the linear function is calculated by the following method:
wherein,V s is the starting threshold voltage of the voltage at which,V s1set to 1.2 times the starting threshold voltage,T s is the time point corresponding to the initial threshold voltage and is marked as the zero point of the collected data,T s1is the time point corresponding to 1.2 times the initial threshold voltage.
The ascending curve scaling function is therefore:
。 (8)
2. calculating the rising curve of 0 toT m The area below;
the curve area of the ascending section is divided into two parts, which are respectively 0 to 0T s Area under time period curveS s AndT s ~T m area under time period curveS m ;0~T s The area under the time period curve is estimated and solved through a proportional function,T s ~T m the area under the time period curve is calculated by sampling the data.
First, estimate 0 toT s The area under the time period curve, which conforms to a linear function, is as follows:
S s= V s ×ΔT s /2 (9)
wherein,ΔT s the time difference from the actual starting point of the curve to the starting threshold point,ΔT s= V s /k,k=0.2×V s /T s1,
therefore, the first and second electrodes are formed on the substrate,
。 (10)
in the second step, the first step is that,T s ~T m area under time period curveS m Performing summation calculation through sampling data;
known rising curve functionf(t)In the intervalT s ,T m ]The upper section is continuous, the section [ 2 ]T s ,T m ]Divided into n subintervalsT 0 , T 1]、[T 1 ,T 2]、[T 2 ,T 3]、…… [T n-1,T n]WhereinT 0=T s ,T n =T m ;
The sampling process keeps the lengths of all the intervals the same, namelyΔtObtaining the number of samples n ═ n: (in this period of time)T m -T s )/Δt; (11)
To pairT s ~T m The time period curve sampling data is summed to obtain the curve area in the time periodS m :
Wherein,f(t i )is composed ofT s ~T m The time period sampling points correspond to the voltage values,Δtfor the sampling time, the number of samples n ═ c (T m - T s )/Δt。ΔtThe smaller the calculation accuracy.
3. And calculating a descending curve function.
First of allStep (1) collecting
T m ~
T e Time period voltage
V m ~
V e And solving a descending curve function. The falling curve of the output voltage of the thermopile detector conforms to the negative exponential function form:
。
wherein,tis the time;V t is time of daytThe real-time output voltage of (2);acoefficients of an exponential function;τis a time constant, is an intrinsic parameter of the thermopile detector, which means that the physical quantity decays from a maximum value to a 1-eTimes (about 0.368 times) the time required.
Calculating the coefficient of the exponential functionaAnd time constantτThere are two methods:
method one, will end the threshold voltageV e Is arranged as0.368V m At this time, the voltage response curve is divided into four stages as shown in fig. 3.
According to the nature of the exponential function, whether exponential function or not
y=a x (
a>0 and
) In (1)
aTaking any value, the function passes through a particular point.
y=e x After passing through the point (0,1),
the process of (0),
a) The point is that, for the falling curve of the output voltage of the thermopile detector,
t 0corresponding output voltage is
V m Obtaining the coefficient of the descending curve exponential function
a=V m 。
τIs that the voltage value decays from a maximum value to a maximum value of 1-
eTime of doubling, output voltage at that time
V τ =0.368V m Therefore, the data acquisition of the real-time output voltage only needs to acquire the maximum value
V m 0.368 times of so willEnd threshold voltage set to
V e =0.368V m Then a time constant is obtained
τ=
T e Thereby obtaining an exponential function of a descending curve
。 (13)
Thus, the method is to end the threshold voltageV e Is arranged asV e =0.368V m Data acquisition and recording by control systemT m ~T e Voltage and time data of the time period are obtainedT e To obtain the time constantτ。
Method two, fitting the curve by least squares method, at which time the threshold voltage will be terminatedV e Is arranged as0.5V m 。
The least squares method is a mathematical optimization algorithm. It finds the best functional match of the data by minimizing the sum of the squares of the errors. Unknown data can be obtained from a sample by the least square method, and the sum of squares of errors between these obtained data and actual data is minimized.
The falling curve of the output voltage of the thermopile detector conforms to the negative exponential function form:
coefficient of order
b=1/
τ,
x=t,y=
V t Then obtain the function
. To function
Taking logarithm on two sides to obtain ln
y=ln
a-
bxIn order to make the water-soluble polymer,
a 0 =lna,
a 1 =-bobtaining a linear model
. Collected by a control system
V m ~
V e The sample data can be solved by using least square method
a 0、
a 1. By
a 0 =lnaTo obtain
(ii) a By
a 1 =-bTo obtain
b=-a 1(ii) a Thereby obtaining a fitting function
。
By using the least square method, the threshold voltage can be adjustedV e Is set to0.5V m The control system only needs to collect and recordV m ~0.5V m The voltage and time data in the range can be fitted to an exponential function of the descending curve, and the ending threshold point in method one is used as (T τ ,V τ ) It is shown that at this time, the voltage response curve is divided into four phases as shown in fig. 4. As can be seen from FIG. 4, the threshold will be terminated compared to method oneV e Is set to0.5V m The testing speed is improved.
4. Calculated under the descending curveT m ~∞Area of (2)
The curve area of the descending section is divided into two parts, respectivelyT m ~T e Area under time period curveS e AndT e ~∞area under time period curveS t ;T m ~T e The area under the time period curve is summed over the sampled data,T e ~∞the area under the time period curve is estimated by integrating with a fitting function.
In the first step, the first step is that,T m ~T e lower aspect of time period curveThe product is summed and calculated through sampling data;
known function of the droop curvey(t)In the intervalT m ,T e ]The upper section is continuous, the section [ 2 ]T m ,T e ]Divided into w subintervalsT 0 , T 1]、[T 1 ,T 2]、[T 2 ,T 3]、…… [T w-1,T w]WhereinT 0=T m ,T w=T e ;
The sampling process keeps the lengths of all the intervals the same, namelyΔtObtaining the sampling number w ═ m (m) in the period of timeT e -T m )/Δt; (14)
To pairT m ~T e The time period curve sampling data is summed to obtain the curve area in the time periodS e :
Wherein,y(t i )is composed ofT m ~T e The time period sampling points correspond to the voltage values,Δtfor the sampling time, the number of samples w ═ c (c)T e - T m )/Δt。
In the second step, the first step is that,T e ~∞area under time period curveS t Performing integral estimation through a fitting function;
T e ~∞area under time period curve
S t The integration equation is as follows:
; (16)
whereinS t Is area of,T e =0,a=V e ,b=1/τ;
Following calculation of the same voltage response curve by setting different end threshold voltagesT m ~∞The area below compares the calculation errors of the two calculation methods.
Take the waveform shown in FIG. 5 as an example, in which the maximum voltage valueV m =1.072(V), time corresponding to maximum voltage valueT m =0, and then a calculation is made to obtain the formula of the curve of the descent process: y =1.072e-1.2576x,τ=1/1.2576。
1) By the method 1, takeV e =0.368V m =0.3945(V), corresponding to timeT e =0.785(s), integral calculationT m ~T e Area under the time period curve, integrated value: 0.5334, calculatingT e ~∞Area under the time period curve:S t =0.3945 ÷ 1.2576= 0.3137. The area of the descending curve obtained by adding the areas of the two sections is as follows: 0.8471 (J).
2) By the method 2, takeV e =0.5V m =0.536(V) corresponding to the time instantT e =0.54(s), integral calculationT m ~T e To obtain an integral value: 0.42107, calculatingT e ~∞Area of (d):S t =0.536 ÷ 1.2576= 0.426201. The area of the descending curve obtained by adding the areas of the two sections is as follows: 0.847271 (J).
The error for both calculation methods is about: 0.02 percent. It follows that both calculation methods result in little error in the calculation results, while determining the ending threshold point in the second manner allows a faster measurement of the optical energy.
5. Calculating the area below the whole curve of 0 to infinity;
the area under the whole curve of 0 to infinity is the sum of four sections of areas:S=S s +S m +S e +S t . The area is corrected by a certain linear coefficient with a standard light source, and then the measured value of the optical energy can be obtained. The optical energy measurements of the incident light were:E=a×S(ii) a Wherein,athe coefficients are corrected for energy calibrated to a standard light source.
As shown in fig. 6, the present invention also provides a fast calculation apparatus for pulse energy measurement, for implementing the above fast calculation method for pulse energy measurement, including a control module 101, a storage module 102, a feature point calculation module 103, an area calculation module 104, and a power calculation module 105; wherein,
the control module 101 is used for coordinating the work of other modules;
a characteristic point calculation module 103 for obtaining an initial threshold point from the voltage response curve measured by the thermopile detector: (T s ,V s ) Maximum point of (a)T m ,V m ) And an end threshold point: (T e ,V e );
An area calculating module 104 for calculating according to the actual sampling dataT s ~T m AndT m ~T e area under the phase correspondence curveS m AndS e and estimating 0 toT s AndT e ~∞area under the phase correspondence curveS s AndS t and calculateS s 、S m 、S e AndS t sum of (2)S;
A power calculation module 105 for calculating the area under the entire curve from 0 to infinitySCalculating the optical energy measurement value of the incident lightE;
The storage module 102 is used for storing the voltage response curve measured by the thermopile detector and all calculation results of the characteristic point calculation module 103, the area calculation module 104 and the power calculation module 105.
Specifically, the feature point calculation module 103 is used to set a starting threshold point (T s ,V s ) And for obtaining a maximum point from the voltage response curve (T m ,V m ) And according to the maximum voltageV m Calculating an end threshold voltageV e And further determining an end threshold point (T e ,V e ). Preferably, the characteristic point calculation module 103 is configured to calculate the ending threshold voltage according to the following formulaV e ,V e =0.368V m Either the first or the second substrate is, alternatively,V e =0.5V m 。
an area calculation module 104 for calculating an area based on the starting threshold point(s) ((T s ,V s ) And 1.2 times the onset threshold point (T s1 ,V s1) Estimate 0 to using equation (2)T s Area under the phase correspondence curveS s :
S s =(V s ×T s1)/0.4, (2)
Wherein,V s is the starting threshold voltage of the voltage at which,V s1set to 1.2 times the starting threshold voltage,T s the time point corresponding to the initial threshold voltage is recorded as the zero point of the collected data,T s1is the time point corresponding to 1.2 times the initial threshold voltage.
An area calculation module 104 for calculating using the following equationT s ~T m Area under curve over time periodS m :
Whereinf(t i )Is composed ofT s ~T m The sampling points correspond to the voltage values of the voltage,Δtfor the sampling time, the number of samples n ═ c (T m -T s )/Δt。
An area calculation module 104 for calculating using the following equationT m ~T e Area under curve over time periodS e :
Whereiny(t i )Is composed ofT m ~T e The sampling points correspond to the voltage values of the voltage,Δtfor the sampling time, the number of samples w ═ c (c)T e -T m )/Δt。
An area calculation module 104 for pairing byT e ~∞Area under time period curveS t And (4) estimating:
wherein,τis 1 ^ or which is the decay of the voltage value from the maximum value to the maximum value in the voltage response curveeTime of the double.
The area calculation module 104 is also used for calculating the area under the whole curve of 0 to infinityS:S=S s +S m +S e +S t 。 (1)
A power calculation module 105 for calculating the optical energy measurement of the incident light according to the following formulaE,E=a×S(ii) a Wherein,aenergy correction system for calibration with standard light sourceAnd (4) counting.
In summary, the fast calculation method for pulse energy measurement provided by the present invention obtains the initial threshold point from the voltage response curve measured by the detector(s) ((T s ,V s ) Maximum point of (a)T m ,V m ) End threshold point: (T e ,V e ) The voltage response curve is according to the time pointT s 、T m 、T e The method comprises four stages in sequence: 0 toT s 、T s ~T m 、T m ~T e 、T e ~∞Then calculates according to the actual sampling dataT s ~T m AndT m ~T e area under the phase correspondence curveS m AndS e and estimating 0 to 0 according to the curve shape characteristic of the voltage response curveT s AndT e ~∞area under the phase correspondence curveS s AndS t and finally, calculating the sum of the areas under the corresponding curves of the four stages, and finally calculating the measured value of the optical energy. By the calculation method, the measured value of the optical energy can be calculated quickly, the test speed can be improved, the change of the incident signal can be measured quickly, the energy value of the incident light can be calculated quickly, the relative measurement deviation is small, and the requirements of high precision and quick response to the detection object in practical application are met.
The above provides a detailed description of the fast calculation method and apparatus for pulse energy measurement provided by the present invention. Any obvious modifications to the invention, which would occur to those skilled in the art, without departing from the true spirit of the invention, would constitute a violation of the patent rights of the invention and would carry a corresponding legal responsibility.