CN204887287U - Device of detection images sensor performance - Google Patents

Abstract

The utility model relates to a device of detection images sensor performance belongs to the optical imaging field. Its method step does: device right side interface and image sensor external frame's left side interface connection forms the enclosure space that does not receive external disturbance, and the laser instrument sends the parallel light and shines and produce the diffraction after having the diffraction screen of hole through adjustable optical attenuation piece, the parallel light after adjusting, and the pixel surface that diffracted ray process convergent lens focused on image sensor forms the diffraction pattern, and the final adjustment adjustable loop focuses on the diffraction pattern. Through the light intensity information of the diffraction spot calibrated, can quantitatively obtain each performance parameter of image sensor. It has overcome traditional test and the control methods shortcomings such as length, complex operation, scene complicacy, analysis difficulty that expend time in, provide one kind do not receive external disturbance, directly perceived, simple and clear, possess the device and the method of miniaturization, portable image sensor capability test with the contrast of qualitative and quantitative function simultaneously fast.

Description

A kind of device of detected image sensor performance

Technical field

The present invention relates to optical imaging field, particularly relate to a kind of device of detected image sensor performance.

Background technology

Imageing sensor, is also called camera, is a kind of photon signal to be converted into analog signal or digital signal, finally by device that data are shown by the form of image or spectrum.Evaluate the quality of a camera, need to consider numerous basic performance parameter, comprise and read noise, photoresponse absolute sensitivity threshold, full well capacity, dynamic range, signal to noise ratio etc.EMVA1288 is the standard method of test for measuring these imageing sensor fundamental performance parameters that EMVA issues---(shield extraneous light completely in rigorous test environment, uniform monochromatic source is produced by integrating sphere, still image transducer makes the optical table etc. of itself and light source strict orthogonal), a large amount of picture sampled datas is obtained under different time for exposure and illumination condition, comparatively accurate performance parameter is obtained through detailed data process&analysis, the performance of contrast different cameral, can directly the data of these corresponding parameters be compared thus reach a conclusion.Accurately, the great advantage that rigorous, systematicness is this method, but also there is several shortcoming: (1) needs to build comparatively complicated, expensive test platform, and test environment not easily builds simultaneously; (2) need to take a large amount of image datas, spend the more time to carry out analyzing and processing to data; (3) contrasted by supplemental characteristic, the performance of different cameral can not be compared intuitively, fast.

By with camera to interfere or striped that diffraction effect produces or spot to observe also be a kind of mode judging camera properties.Chinese invention patent, publication number: CN104065956A, publication date: 2014.09.24, discloses a kind of detection and caliberating device of imageing sensor, comprising: a light source, for providing a light beam; This light beam interferes after the first grating, lens and the second grating; This interference image gathers through this imageing sensor, detects and demarcates this imageing sensor, it is characterized in that according to this interference image, and the cycle that cycle of this first grating equals this second grating is multiplied by 3 multiplying powers of these lens.Its weak point is: (1) can only be used for measurement sensistivity and the linearity, cannot measure other parameter of camera; (2) measuring process is loaded down with trivial details, needs to obtain multiple view data; (3) performance parameter of different cameral fast, intuitively cannot be compared by view data.

For Fraunhofer diffraction method, not yet there are complete camera properties contrast and the system schema demarcated at present.In addition, traditional Fraunhofer diffraction device will be built by optical table, and each element is in discrete state, does not form a complete totally enclosed system, can be subject to the impact of surround lighting, and the volume of device is comparatively huge, is not suitable for portable fast detecting.

When showing with contrast camera properties, whether mode more directly perceived simple observes the picture that different cameras takes same scene to there are differences.Such as take bioluminescence image, can be judged the reading noise of different cameral, light responsing sensitivity roughly by the intensity level of the signal and background noise of observing two width images or contrast; The gray value of the sample signal obtained by two width pictures relatively can expire well capacity.But the shortcoming of this mode is: scene is in fact too complicated, simplifies not enough, the light interference by surrounding is comparatively large, can only compare to performance roughly, and contrast project is too single, more cannot estimate in amount.

In sum, there are two kinds of modes with control methods in current image sensor performance test: the qualitative and quantitative that (1) can realize camera parameter performance is measured, but device is too complicated, and system bulk is comparatively large, and testing efficiency is lower; (2) can qualitatively judge, but mode is too coarse Fast Fuzzy, cannot Systematic Analysis be carried out.Therefore, study a kind of quick, directly perceived, simple, portable and can to image sensor performance carry out qualitative compare and the device of quantitative measurment particularly important.

Summary of the invention

1. the technical problem solved

Scene complexity is there is in image sensor performance contrast and method of testing in prior art, image real time transfer is slow, measuring process is complicated, can not quantitative measurment, problem not intuitively, the present invention proposes a kind of device of detected image sensor performance, it can realize fast, the performance parameter of directly perceived, simple, quantitative measurment and qualitative contrast images transducer.

2. technical scheme

For solving the problem, technical scheme provided by the invention is:

A kind of device of detected image sensor performance, comprise variable optical attenuation sheet, convergent lens, laser, diffraction screen and adjustable loop, wherein, described laser, variable optical attenuation sheet, diffraction screen, convergent lens and adjustable loop are fixed in described device successively, the right side of adjustable loop is provided with imageing sensor, and the left end of described laser is provided with cable interface.For every image sensors, only need obtain an image, can carry out qualitative and quantitative test to imageing sensor by the level time of the diffraction spot photographed with intensity signal, operating procedure is succinct, compare other technologies, more intuitive, clear to the contrast of imageing sensor.

The effect of described laser is the directional light producing a branch of monochrome, the decay light source that act as of described variable optical attenuation sheet is irradiated to light intensity on diffraction screen, the effect of described diffraction screen is the directional light generation diffraction making to be irradiated on diffraction screen hole, the effect of described convergent lens makes diffracted beam by focusing on after convergent lens, form diffraction spot, described adjustable loop can carry out rotating adjustment thus change the distance of convergent lens to image sensor chip surface, the imaging of diffraction spot is focused on further, the pixel being finally irradiated to imageing sensor forms diffraction pattern clearly on the surface.

Preferably, the cable interface of the left end of described laser is electrically connected by cable with power supply, for the power supply of connecting laser, makes laser send monochromatic collimated beam.

Preferably, the left side interface of the interface on the right side of described device and imageing sensor external frame links together, and is formed not by the enclosure space of extraneous light interference.By regulating the imaging of adjustable loop to diffraction spot to focus on, make diffraction spot blur-free imaging.

Preferably, the shape of the hole on diffraction screen is rectangle or circle, and the shape of diffraction pattern and position are determined by the focal length of the size of the void shape on diffraction screen, void shape, incident wavelength and convergent lens; Diffraction spot is short and sweet, is rich in stereovision, comprises abundant intensity signal, is suitable as standard testing pattern.

Preferably, the overall length of described device is 150mm, and maximum gauge is 50mm, i.e. device each several part cross section, and wherein the diameter of maximum cross section is 50mm.Described device has miniaturization, advantage portable, with low cost, without the need to the instrument and equipment of complexity, test condition and experimental implementation, can be connected fast carry out contrasting and test from different imageing sensors.

A using method for the device of detected image sensor performance, its step is as follows:

A, build the device of above-described a kind of detected image sensor performance;

B, the cable interface of laser left end to be connected with power supply, open laser, laser sends directional light, through variable optical attenuation sheet, directional light after variable optical attenuation sheet regulates is radiated at after on the pertusate diffraction screen of band and produces diffraction, and diffracted ray focuses on through convergent lens, forms diffraction spot, focus on further through the imaging of adjustable loop to diffraction spot, the pixel being finally irradiated to imageing sensor forms diffraction pattern on the surface again;

C, by regulating the light intensity of power to diffraction pattern of laser to adjust, laser regulates the position of laser control luminous power, i.e. button, button or software design patterns etc., the light intensity of the directional light that laser sends is adjusted, correspondingly, the intensity signal of the diffraction pattern on imageing sensor can be regulated, for the intensity signal calibrating diffraction pattern in step D is prepared;

The intensity signal of D, calibration diffraction spot:

Step C can change the intensity signal of diffraction spot, and can be changed the size of diffraction spot by the size changing void shape on diffraction screen and void shape, its computing formula is:

$D_k=\frac{\mathrm{\λ}}{a}f;$

Wherein, f is the focal length of convergent lens, and λ is the lambda1-wavelength that laser sends, a is the size of void shape on diffraction screen, if void shape is rectangle, the size of void shape refers to the length of rectangle and wide, if void shape is circular, the size of void shape refers to diameter of a circle, D _kfor the size of formed diffraction spot;

Measured the number of photons received by the unit interval unit are of the Zero-order diffractive spot produced by spectrometer or standard image sensor, the photon number recording the per area per time corresponding to Zero-order diffractive spot is I ₀, for the photon information of other diffraction spots at different levels, according to formula

$I_k={\[(k+\frac{1}{2})\mathrm{\π}\]}^{-2}{I}_0$

The number of photons of diffraction spot at different levels is solved; Wherein, I _kfor the number of photons that the unit interval unit are of kth order diffraction spot receives, thereby, it is possible to obtain the number of photons information corresponding to diffraction spot at different levels.

The performance parameter of E, qualitative comparative analysis different images transducer:

According to the diffraction pattern intensity signal calibrated in step D, take same width diffraction spot image by camera software control different images transducer, the gray value taking the order of diffraction time k and the corresponding stage time diffraction spot observed by comparing different images transducer carries out qualitative comparison to sensitivity, dynamic range, reading noise, signal to noise ratio and full well capacity:

Time k is higher for the order of diffraction that can observe, and the detectivity of imageing sensor is higher;

Time k is higher for the order of diffraction that can observe, and the reading noise of imageing sensor is less;

Meanwhile, show that, when receiving same light subnumber, the signal to noise ratio of imageing sensor is higher;

Carry out qualitative comparative analysis to the bright-dark degree gone out shown by same unsaturated more rudimentary diffraction spot, the imageing sensor that diffraction spot display is brighter by comparing different images transducer, its full well capacity is less, and maximum signal to noise ratio is larger;

By comparing different images transducer, the secondary interval range of maximum diffraction level or number are arrived to the unsaturated minimum diffraction level time that same width diffraction pattern can be observed, its dynamic range of expression that scope is larger is larger, and its dynamic range of expression that scope is less is less;

F, quantitatively obtain each performance parameter of single image transducer;

The performance parameter of imageing sensor comprises photoresponse absolute sensitivity threshold, reading noise, full well capacity, entire system gain, maximum signal to noise ratio SNR _maxwith dynamic range DR;

Photoresponse absolute sensitivity threshold:

By image processing software, as Photoshop, ImageJ, auto contrast's adjustment is carried out to the picture of imageing sensor shooting, observe the maximum diffraction level time k of the diffraction spot that imageing sensor can be told _max, from step D, obtain diffraction progression is k _maxtime, the number of photons I of diffraction spot per area per time _k.max, calculate actual detectable minimum number of photons thus, obtain photoresponse absolute sensitivity threshold:

Wherein, I _k.maxthe number of photons that the unit interval unit are that the highest diffraction spot can told for imageing sensor is corresponding produces, t _expfor the time for exposure of imageing sensor, A is the single pixel area of imageing sensor;

Read noise:

According to the photoresponse absolute sensitivity threshold μ of imageing sensor _p.minwith the quantum efficiency η of imageing sensor, the quantum efficiency η of imageing sensor is recorded by quantum efficiency tester, the reading noise of quantitative computed image transducer, and its computing formula is as follows:

${\mathrm{\σ}}_d\≈{\mathrm{\η\μ}}_{p\·\min }-\frac{1}{2}$

Full well capacity:

By image processing software, as Photoshop, ImageJ, the gray value μ of the diffraction spot of known number of photons information in the diffraction image that measurement image transducer has been taken _y.k, be namely respectively μ _y.0, μ _y.1, μ _y.2, μ _y.3, μ _y.4... μ _y.k, correspond to 0,1,2,3,4 ... .k the gray value of order diffraction spot, the full well capacity of quantitative computed image transducer;

1) if the gray value μ of certain k order diffraction spot _y.k0.891 (2 ^b-1) ~ 0.909 (2 ^b-1) time in scope, namely 90% 2 ^b-1, the margin of tolerance 1%, then the electron number that the pixel that this diffraction spot is corresponding produces is full well capacity, and expression formula is:

μ _e.sat＝ημ _p.sat＝η·I _k.sat·t _exp·A

Wherein, 2 ^b-1 maximum gradation value that can reach for image, the data bits of b presentation video, η is the quantum efficiency of imageing sensor, t _expfor the time for exposure of imageing sensor, A is the single pixel area of imageing sensor, I _k.satthe gray value μ of k order diffraction spot _y.k0.891 (2 ^b-1) ~ 0.909 (2 ^b-1) time in scope, the number of photons of the per area per time corresponding to k order diffraction spot, μ _p.satfor the saturated light subnumber that imageing sensor can receive;

2) if diffraction spot does not meet 1) condition, select the diffraction spot that in diffraction image, any one grade is secondary, measure its gray value, now completely the calculating formula of well capacity is:

${\mathrm{\μ}}_{e\·sat}=0.9(2^b-1)\frac{{\mathrm{\η\μ}}_{p\·k}}{{\mathrm{\μ}}_{y\·k}-{\mathrm{\μ}}_{y\·dark}}$

μ _p·k＝I _k·t _exp·A

Wherein, b is the data bits of image, μ _y.darkfor the background gray value of camera, μ _ykfor the gray value of the diffraction spot of selected level time, μ _pkfor the number of photons of the single pixel of the diffraction spot of selected level time; I _kfor the number of photons of the diffraction spot unit interval unit are of selected level time, t _expfor the time for exposure of imageing sensor, A is the single pixel area of imageing sensor.

Entire system gain:

The gray value μ that diffraction progression is the diffraction spot of k is measured by image processing software _y.k, and the background gray value μ of camera _y.dark, quantitatively calculate the value of the entire system gain K of camera, its computing formula is as follows:

$K=\frac{{\mathrm{\μ}}_{y.k}-{\mathrm{\μ}}_{y.dark}}{{\mathrm{\η\μ}}_{p.k}};$

Wherein, μ _p.kfor the number of photons that the single pixel-by-pixel basis of this order of diffraction time correspondence receives, μ _y.darkfor the background gray value of camera.

Maximum signal to noise ratio SNR _max:

The full well capacity μ of the imageing sensor that known said method is tried to achieve _e.sat, the computing formula of maximum signal to noise ratio is:

${\mathrm{SNR}}_{max}\≈\sqrt{{\mathrm{\μ}}_{e.sat}};$

Dynamic range DR:

The full well capacity μ of the imageing sensor that known said method is tried to achieve _e.satand read noise σ _d, the computing formula of dynamic range is:

$DR=\frac{{\mathrm{\μ}}_{e.sat}}{{\mathrm{\σ}}_d}.$

From the above, can be calculated each fundamental performance parameter of imageing sensor by diffraction spot.

G, test for each imageing sensor after, close laser, and the electrical connection of the cable interface of laser and power supply to be disconnected, imageing sensor is taken off on the right side of described device.

Preferably, the void shape on described diffraction screen is rectangle or circle.

Preferably, by selecting the variable optical attenuation sheet installing differential declines multiplying power, also can adjust the light intensity of diffraction pattern, for the intensity signal calibrating diffraction pattern in step D is prepared.

3. beneficial effect

Adopt technical scheme provided by the invention, compared with prior art, there is following beneficial effect:

(1) laser, variable optical attenuation sheet, diffraction screen, convergent lens and adjustable loop are fixed in device of the present invention successively, on the right side of device, the left side interface of interface and imageing sensor external frame links together, formed not by the enclosure space of extraneous light interference, do not need to build comparatively complicated, expensive test platform, test environment easily builds;

(2) the present invention is for every image sensors, do not need to take a large amount of image datas, the more time is spent to carry out analyzing and processing to data, only need obtain an image, qualitative contrast and quantitative test can be carried out to imageing sensor by the level time of the diffraction spot photographed with intensity signal;

(3) after building device of the present invention, open laser, send directional light, the optical attenuation sheet of differential declines multiplying power is installed by the power or selection regulating laser, the light intensity of diffraction pattern is adjusted, form diffraction pattern clearly, then the intensity signal of diffraction spot is calibrated, the performance parameter of qualitative comparative analysis different images transducer, quantitatively obtain each performance parameter of single image transducer, finally close laser, imageing sensor is taken off on the right side of described device; Operating procedure is succinct, compares other technologies, is contrasted by supplemental characteristic, can compare the performance of different images transducer intuitively, fast;

(4) overall length of device of the present invention is 150mm, each several part cross section in device, wherein the diameter of maximum cross section is 50mm, there is miniaturized, portable, with low cost advantage, without the need to the instrument and equipment of complexity, test condition and experimental implementation, can be connected from different imageing sensors fast and carry out contrasting and test;

(5) right-hand member of variable optical attenuation sheet of the present invention is provided with diffraction screen, and the shape of the hole on diffraction screen is rectangle or circle; The shape of diffraction pattern and position are determined by the focal length of the size of the void shape on diffraction screen, void shape, incident wavelength and convergent lens; Diffraction spot is short and sweet, and scene is simple, and be rich in stereovision, comprise abundant intensity signal, the light not by surrounding disturbs, and is suitable as standard testing pattern.

Accompanying drawing explanation

Fig. 1 is device schematic diagram of the present invention.

Number in the figure:

1, laser; 11, power supply; 2, variable optical attenuation sheet; 3, diffraction screen; 4, convergent lens; 5, adjustable loop; 6, imageing sensor.

Embodiment

For understanding content of the present invention further, by reference to the accompanying drawings and embodiment the present invention is described in detail.

Embodiment 1

Composition graphs 1, a kind of device of detected image sensor performance, comprise variable optical attenuation sheet 2, convergent lens 4, laser 1, diffraction screen 3 and adjustable loop 5, wherein, described laser 1, variable optical attenuation sheet 2, diffraction screen 3, convergent lens 4 and adjustable loop 5 are fixed in described device successively, and the right side of adjustable loop 5 is provided with imageing sensor 6, and the left end of described laser 1 is provided with cable interface, be electrically connected by cable with power supply 11, make laser 1 send monochromatic collimated beam; The light intensity of the directional light that laser 1 can be regulated to send by regulating the power of laser 1, correspondingly, can adjust the light intensity of diffraction pattern; By installing the variable optical attenuation sheet 2 of differential declines multiplying power, light source of also can decaying is irradiated to the light intensity of diffraction screen 3, adjusts the light intensity of diffraction pattern.

The shape of the hole on diffraction screen 3 is rectangle or circle, and the shape of diffraction pattern and position are determined by the focal length of the size of the void shape on diffraction screen 3, void shape, incident wavelength and convergent lens 4; Diffraction spot is short and sweet, and scene is simple, and be rich in stereovision, comprise abundant intensity signal, the light not by surrounding disturbs, and is suitable as standard testing pattern.

The left side interface of the interface on the right side of device and external frame links together, and is formed not by the enclosure space of extraneous light interference; Described laser 1, variable optical attenuation sheet 2, diffraction screen 3, convergent lens 4 and adjustable loop 5, being fixed in device by specific groove or screw socket, to be matched with the screw thread on device by screw socket and is fixed in device in the side be connected with power supply 11 as laser 1; Variable optical attenuation sheet 2, diffraction screen 3 and convergent lens 4 are all fixed in device by the groove of the corresponding position on device inwall; The middle part of adjustable loop 5 there is a circle protruding, be fixed in device with the fit depressions of the corresponding position on device inwall; Do not need to build comparatively complicated, expensive test platform, test environment easily builds.

The effect of described laser 1 is the directional light producing a branch of monochrome, the decay light source that act as of described variable optical attenuation sheet 2 is irradiated to the light intensity of diffraction screen 3, the effect of described diffraction screen 3 is the directional light generation diffraction making to be irradiated on diffraction screen 3 hole, the effect of described convergent lens 4 makes diffracted beam by focusing on after convergent lens 4, form diffraction spot, described adjustable loop 5 can carry out rotating adjustment thus change the distance of convergent lens 4 to imageing sensor 6 chip surface, the imaging of diffraction spot is focused on further, the pixel being finally irradiated to imageing sensor 6 forms diffraction pattern clearly on the surface.

For every image sensors 6, do not need to take a large amount of image datas, spend the more time to carry out analyzing and processing to data, only need obtain an image, qualitative and quantitative test can be carried out to imageing sensor 6 by the level time of the diffraction spot photographed with intensity signal; Operating procedure is succinct, compares other technologies, is contrasted by supplemental characteristic, can compare the performance of different images transducer 6 intuitively, fast.

The overall length of device is 150mm, maximum gauge is 50mm, i.e. device each several part cross section, wherein the diameter of maximum cross section is 50mm, device has miniaturization, advantage portable, with low cost, without the need to the instrument and equipment of complexity, test condition and experimental implementation, can be connected from different imageing sensors fast and carry out contrasting and test.

A using method for the device of detected image sensor performance, its step is as follows:

A, build the device of above-described a kind of detected image sensor performance;

B, the cable interface of laser 1 left end to be connected with power supply 11, open laser 1, laser 1 sends directional light, through variable optical attenuation sheet 2, directional light after variable optical attenuation sheet 2 regulates is radiated at after on the pertusate diffraction screen 3 of band and produces diffraction, and diffracted ray focuses on through convergent lens 4, forms diffraction spot, imaging again through adjustable loop 5 pairs of diffraction spots focuses on further, and the pixel being finally irradiated to imageing sensor 6 forms diffraction pattern on the surface;

C, by regulating the light intensity of power to diffraction pattern of laser 1 to adjust, laser 1 regulate laser 1 control the position of luminous power, i.e. button, button or software design patterns etc., the light intensity of the directional light that laser 1 sends is adjusted, correspondingly, the intensity signal of the diffraction pattern on imageing sensor 6 can be regulated, for the intensity signal calibrating diffraction pattern in step D is prepared; Regulating the optical attenuation sheet 2 by selecting to install differential declines multiplying power, also can adjust the light intensity of diffraction pattern.

The intensity signal of D, calibration diffraction spot:

Step C can change the intensity signal of diffraction spot, and can be changed the size of diffraction spot by the size changing void shape on diffraction screen 3 and void shape, its computing formula is:

$D_k=\frac{\mathrm{\λ}}{a}f;$

Wherein, f is the focal length of convergent lens 4, and λ is the lambda1-wavelength that laser 1 sends, and a is the size of void shape on diffraction screen 3, and the void shape on diffraction screen 3 is rectangle or circle; If void shape is rectangle, the size of void shape refers to the length of rectangle and wide, if void shape is circular, the size of void shape refers to diameter of a circle, D _kfor the size of formed diffraction spot;

Measured the number of photons received by the unit interval unit are of the Zero-order diffractive spot produced by spectrometer or standard image sensor, the photon number recording the per area per time corresponding to Zero-order diffractive spot is I ₀.For the photon information of other diffraction spots at different levels, according to formula:

$I_k={\[(k+\frac{1}{2})\mathrm{\π}\]}^{-2}{I}_0$

The number of photons of diffraction spot at different levels is solved; Wherein, I _kfor the number of photons that the unit interval unit are of kth order diffraction spot receives, thereby, it is possible to obtain the number of photons information corresponding to diffraction spot at different levels;

The performance parameter of E, qualitative comparative analysis different images transducer 6:

According to the diffraction pattern intensity signal calibrated in step D, take same width diffraction spot image by camera software control different images transducer 6, the gray value taking the order of diffraction time k and the corresponding stage time diffraction spot observed by comparing different images transducer 6 carries out qualitative comparison to sensitivity, dynamic range, reading noise, signal to noise ratio and full well capacity:

Time k is higher for the order of diffraction that can observe, and the detectivity of imageing sensor 6 is higher;

Time k is higher for the order of diffraction that can observe, and the reading noise of imageing sensor 6 is less;

Meanwhile, show that, when receiving same light subnumber, the signal to noise ratio of imageing sensor 6 is higher;

Carry out qualitative comparative analysis to the bright-dark degree gone out shown by same unsaturated more rudimentary diffraction spot, the imageing sensor 6 that diffraction spot display is brighter by comparing different images transducer 6, its full well capacity is less, and maximum signal to noise ratio is larger;

By comparing different images transducer 6, the secondary interval range of maximum diffraction level or number are arrived to the unsaturated minimum diffraction level time that same width diffraction pattern can be observed, its dynamic range of expression that scope is larger is larger, and its dynamic range of expression that scope is less is less;

F, quantitatively obtain each performance parameter of single image transducer 6;

The performance parameter of imageing sensor 6 comprises photoresponse absolute sensitivity threshold, reading noise, full well capacity, entire system gain, maximum signal to noise ratio SNR _maxwith dynamic range DR;

Photoresponse absolute sensitivity threshold:

By image processing software, as Photoshop, ImageJ, auto contrast's adjustment is carried out to the picture that imageing sensor 6 is taken, observe the maximum diffraction level time k of the diffraction spot that imageing sensor 6 can be told _max, from step D, obtain diffraction progression is k _maxtime, the number of photons I of diffraction spot per area per time _k.max, calculate actual detectable minimum number of photons thus, obtain photoresponse absolute sensitivity threshold:

Wherein, I _k.maxthe number of photons that the unit interval unit are that the highest diffraction spot can told for imageing sensor 6 is corresponding produces, t _expfor the time for exposure of imageing sensor 6, A is the single pixel area of imageing sensor 6;

Read noise:

According to the photoresponse absolute sensitivity threshold μ of imageing sensor 6 _p.minwith the quantum efficiency η of imageing sensor 6, the quantum efficiency of imageing sensor 6 is obtained by the measurement of quantum efficiency tester, the reading noise of quantitative computed image transducer 6, and its computing formula is as follows:

${\mathrm{\σ}}_d\≈{\mathrm{\η\μ}}_{p\·\min }-\frac{1}{2}$

Full well capacity:

By image processing software, as Photoshop, ImageJ, the gray value μ of the diffraction spot of known number of photons information in the diffraction image that measurement image transducer 6 has been taken _y.k, be namely respectively μ _y.0, μ _y.1, μ _y.2, μ _y.3, μ _y.4... μ _y.k, correspond to 0,1,2,3,4 ... .k the gray value of order diffraction spot, the full well capacity of quantitative computed image transducer 6;

1) if the gray value μ of certain k order diffraction spot _y.k0.891 (2 ^b-1) ~ 0.909 (2 ^b-1) time in scope, then the electron number that the pixel that this diffraction spot is corresponding produces is full well capacity, and expression formula is:

μ _e.sat＝ημ _p.sat＝η·I _k.sat·t _exp·A

Wherein, 2 ^b-1 maximum gradation value that can reach for image, the data bits of b presentation video, η is the quantum efficiency of imageing sensor 6, t _expfor the time for exposure of imageing sensor 6, A is the single pixel area of imageing sensor 6, I _k.satgray value μ _y.k0.891 (2 ^b-1) ~ 0.909 (2 ^b-1) time in scope, the number of photons of the per area per time corresponding to k order diffraction spot, μ _p.satfor the saturated light subnumber that imageing sensor 6 can receive;

2) if diffraction spot does not meet 1) condition, select the diffraction spot that in diffraction image, any one grade is secondary, measure its gray value, now completely the calculating formula of well capacity is:

${\mathrm{\μ}}_{e\·sat}=0.9(2^b-1)\frac{{\mathrm{\η\μ}}_{p\·k}}{{\mathrm{\μ}}_{y\·k}-{\mathrm{\μ}}_{y\·dark}}$

μ _p·k＝I _k·t _exp·A

Wherein, b is the data bits of image, μ _y.darkfor the background gray value of camera, μ _ykfor the gray value of the diffraction spot of selected level time, μ _pkfor the number of photons of the single pixel of the diffraction spot of selected level time; I _kfor the number of photons of the diffraction spot unit interval unit are of selected level time, t _expfor the time for exposure of imageing sensor 6, A is the single pixel area of imageing sensor 6.

Entire system gain:

The gray value μ that diffraction progression is the diffraction spot of k is measured by image processing software _y.k, and the background gray value μ of camera _y.dark, quantitatively calculate the value of the entire system gain K of camera, its computing formula is as follows:

$K=\frac{{\mathrm{\μ}}_{y.k}-{\mathrm{\μ}}_{y.dark}}{{\mathrm{\η\μ}}_{p.k}};$

Wherein μ _p.kfor the number of photons that the single pixel-by-pixel basis of this order of diffraction time correspondence receives, μ _y.darkfor the background gray value of camera.

Maximum signal to noise ratio SNR _max:

The full well capacity μ of the imageing sensor 6 that known said method is tried to achieve _e.sat, the computing formula of maximum signal to noise ratio is:

${\mathrm{SNR}}_{max}\≈\sqrt{{\mathrm{\μ}}_{e.sat}};$

Dynamic range DR:

The full well capacity μ of the imageing sensor 6 that known said method is tried to achieve _e.satand read noise σ _d, the computing formula of dynamic range is:

$DR=\frac{{\mathrm{\μ}}_{e.sat}}{{\mathrm{\σ}}_d}.$

From the above, can be calculated each fundamental performance parameter of imageing sensor 6 by diffraction spot.

F, test for each imageing sensor 6 after, close laser 1, the electrical connection of the cable interface of laser 1 and power supply 11 is disconnected, imageing sensor 6 is taken off on the right side of described device.

Embodiment 2

As shown in Figure 1, the invention provides a kind of device and using method thereof of detected image sensor performance, structure and using method are with embodiment 1, wherein, first together with described device being closely connected with camera by adjustable loop 5, the cable interface of laser 1 is connected with power supply 11 by cable, opening laser 1 makes it send monochromatic light, the light intensity that monochromatic light sends through variable optical attenuation sheet 2 pairs of lasers 1 regulates and controls, directional light after regulation and control is got on diffraction screen 3 and diffraction is occurred, diffracted beam is assembled by convergent lens 4, through adjustable loop 5, arrival scalable video transducer 6 or imageing sensor 6 to be measured are on the surface, open camera to take, diffraction spot blur-free imaging is made by regulating adjustable loop 5.

In the present embodiment, square aperture shape chosen by diffraction screen 3, and the length of side a of hole is 20um, and the monochromatic wavelength λ that known laser device 1 sends is 625nm, and the focal distance f of convergent lens 4 is 10mm, according to formula

$D_k=\frac{\mathrm{\λ}}{a}f,$

Zero-order diffractive spot D ₀size be 312um, be the imageing sensor 6 of 10um for Pixel size, will the position of 31 pixels be occupied.

In order to each performance parameter value of quantitative measurment, with the imageing sensor 6 of spectrometer or a known performance, certain Advanced Diffraction spot is calibrated, can photon number be regulated by the power of the decay multiplying power and laser 1 that regulate variable optical attenuation sheet 2.The known average photon number recording each hundred square micron of Zero-order diffractive spot every millisecond is 50000, then the number of photons of other diffraction spots at different levels is according to formula:

$I_k={\[(k+\frac{1}{2})\mathrm{\π}\]}^{-2}{I}_0$

Obtain the number of photons of at different levels diffraction spots, as table 1.

The number of photons of table 1 at different levels diffraction spots

Diffraction spot level time k	0	1	2	3	4	5	6	7
									Number of photons	50000	2252	811	414	250	167	120	90
Diffraction spot level time k	8	9	10	11	12	13	14	15
									Number of photons	70	56	46	38.3	32.4	27.8	24	21
Diffraction spot level time k	16	17	18	19	20	21
									Number of photons	18.6	16.5	14.8	13	12	10

Particularly, how the process of qualitative and quantitative test carried out to camera as follows:

(1) sensitivity, completely the well capacity parameter of fast qualitative contrast different cameral

The single Pixel size arranging two cameras one and camera two is 10um, and the time for exposure is 1ms, and so, single pixel area A is 100um ², the superlative degree time observing the diffraction pattern of shooting is respectively 17 and 21, then the sensitivity of camera one is lower than camera two, and the dynamic range of camera two is higher than camera one;

Observed the gray value of the Advanced Diffraction spot of each camera by image processing software ImageJ, record the gray value of gray value higher than camera two of camera one, then the full well capacity of camera one is lower than camera two.

Known camera one is 60% with the quantum effect η of camera two, and because camera two can observe higher diffraction spot level time, then the reading noise ratio camera one of camera two is little, and the signal to noise ratio of camera two is larger than camera one.

(2) concrete quantitative computational process, for camera two:

By table 1, the 21st grade of corresponding number of photons I in the diffraction image captured by known camera two _21.maxbe 10 number of photons, quantum efficiency η is 60%, and the single pixel area A of imageing sensor 6 is 100um ², time for exposure t _expfor 1ms, according to formula

μ _p.min＝I _k.max·t _exp·A，

Photoresponse absolute sensitivity threshold is 10 electronics.

According to formula

${\mathrm{\σ}}_d\≈{\mathrm{\η\μ}}_{p\·\min }-\frac{1}{2},$

Reading noise is 5.5 electronics.

The data bits of image is 12, and the maximum gradation value that image can reach is 2 ^b-1=4095, calculates the 1st of full well capacity according in embodiment 1) in kind situation, the gray value μ of certain k order diffraction spot _y.kscope 0.891 (2 ^b-1) ~ 0.909 (2 ^b-1), calculate in the present embodiment and get final product: 3648 ~ 3722, being recorded the gray value μ of the first-order diffraction spot of the diffraction image that camera two is taken by software _y1being 3500, not within the scope of this, so full well capacity is with the 2nd) kind situation calculates, background background gray value μ _y.darkbe 150, the number of photons I of each hundred square micron of first-order diffraction spot every millisecond ₁it is 2252, according to formula

μ _p·k＝I _k·t _exp·A，

Calculate, the number of photons μ of the single pixel of first-order diffraction spot _p1it is 2252, according to formula

${\mathrm{\μ}}_{e\·sat}=0.9(2^b-1)\frac{{\mathrm{\η\μ}}_{p\·k}}{{\mathrm{\μ}}_{y\·k}-{\mathrm{\μ}}_{y\·dark}},$

Full well capacity μ _esatbe 1487 electronics.

The number of photons μ that the single pixel-by-pixel basis of first-order diffraction spot receives _p.1be 2252, the gray value μ of first-order diffraction spot _y.1be 3500, the background gray value μ of camera two _y.darkbe 150, according to formula

$K=\frac{{\mathrm{\μ}}_{y.k}-{\mathrm{\μ}}_{y.dark}}{{\mathrm{\η\μ}}_{p.k}},$

Entire system yield value K is 2.48DN/e.

The full well capacity μ of known camera two of having tried to achieve _e.satbe 1487, according to formula

${\mathrm{SNR}}_{max}\≈\sqrt{{\mathrm{\μ}}_{e.sat}},$

Maximum signal to noise ratio is 39:1.

The full well capacity μ of known camera two of having tried to achieve _e.satbe 1487, read noise σ _dbe 5.5 electronics, according to formula

$DR=\frac{{\mathrm{\μ}}_{e.sat}}{{\mathrm{\σ}}_d},$

Dynamic range DR is 270:1.

Embodiment 3

Device of the present invention is measured the performance parameters of camera three, and its structure and using method are with embodiment 1.The data bits of image is 12, and the maximum gradation value that image can reach is 2 ^b-1=4095, calculates the 1st of full well capacity according in embodiment 1) in kind situation, the gray value μ of certain k order diffraction spot _y.kscope 0.891 (2 ^b-1) ~ 0.909 (2 ^b-1), calculate in the present embodiment and get final product: 3648 ~ 3722, being recorded the gray value μ of the first-order diffraction spot of the diffraction image that camera three is taken by software _y1being 3648, within the scope of this, so the calculating of full well capacity uses the 1st) kind situation calculates, background background gray value μ _y.darkbe 150, the number of photons I of each hundred square micron of first-order diffraction spot every millisecond ₁be 2252, quantum effect η is 60%, and single pixel area A is 100um ², time for exposure t _expfor 1ms, according to formula

μ _e.sat＝ημ _p.sat＝η·I _k.sat·t _exp·A，

I _ksati.e. I ₁be 2252, calculate, full well capacity μ _e.satbe 1351 electronics.

The number of photons μ that the single pixel-by-pixel basis of first-order diffraction spot receives _p.1be 2252, the gray value μ of first-order diffraction spot _y.1be 3648, the background gray value μ of camera three _y.darkbe 150, according to formula

$K=\frac{{\mathrm{\μ}}_{y.k}-{\mathrm{\μ}}_{y.dark}}{{\mathrm{\η\μ}}_{p.k}},$

Entire system yield value K is 2.59DN/e.

The full well capacity μ of known camera three of having tried to achieve _e.satbe 1351, according to formula

${\mathrm{SNR}}_{max}\≈\sqrt{{\mathrm{\μ}}_{e.sat}},$

Maximum signal to noise ratio is 37:1.

The full well capacity μ of known B camera of having tried to achieve _e.satbe 1351, read noise σ _dbe 5.5 electronics, according to formula

$DR=\frac{{\mathrm{\μ}}_{e.sat}}{{\mathrm{\σ}}_d},$

Dynamic range DR is 246:1, and the value of photoresponse absolute sensitivity threshold, reading noise is with embodiment 2.

Embodiment 4

Device of the present invention is measured the performance parameters of certain camera four, and its structure and using method are with embodiment 1.The data bits of image is 12, and the maximum gradation value that image can reach is 2 ^b-1=4095, calculates the 1st of full well capacity according in embodiment 1) in kind situation, the gray value μ of certain k order diffraction spot _y.kscope 0.891 (2 ^b-1) ~ 0.909 (2 ^b-1), calculate in the present embodiment and get final product: 3648 ~ 3722, being recorded the gray value μ of the first-order diffraction spot of the diffraction image that camera four is taken by software _p.1being 3722, within the scope of this, so the calculating of full well capacity uses the 1st) kind situation calculates, background background gray value μ _y.darkbe 150, the number of photons I of each hundred square micron of first-order diffraction spot every millisecond ₁be 2252, quantum effect η is 60%, and single pixel area A is 100um ², time for exposure t _expfor 1ms, according to formula

μ _e.sat＝ημ _p.sat＝η·I _k.sat·t _exp·A，

I _ksati.e. I ₁be 2252, calculate, full well capacity μ _e.satbe 1351 electronics.

The number of photons μ that the single pixel-by-pixel basis of first-order diffraction spot receives _p.1be 2252, the gray value μ of first-order diffraction spot _y.1be 3722, the background gray value μ of camera four _y.darkbe 150, according to formula

$K=\frac{{\mathrm{\μ}}_{y.k}-{\mathrm{\μ}}_{y.dark}}{{\mathrm{\η\μ}}_{p.k}},$

Entire system yield value K is 2.64DN/e.Maximum signal to noise ratio SNR _maxwith the value of dynamic range DR with embodiment 3, photoresponse absolute sensitivity threshold, read the value of noise with embodiment 2.

Embodiment 5

Device of the present invention is measured the performance parameters of certain camera five, and its structure and using method are with embodiment 1.The data bits of image is 12, and the maximum gradation value that image can reach is 2 ^b-1=4095, calculates the 1st of full well capacity according in embodiment 1) in kind situation, the gray value μ of certain k order diffraction spot _y.kscope 0.891 (2 ^b-1) ~ 0.909 (2 ^b-1), calculate in the present embodiment and get final product: 3648 ~ 3722, being recorded the gray value μ of the first-order diffraction spot of the diffraction image that camera five is taken by software _ybeing 3700, within the scope of this, so the calculating of full well capacity uses the 1st) kind situation calculates, background background gray value μ _y.darkbe 150, the number of photons I of each hundred square micron of first-order diffraction spot every millisecond ₁be 2252, quantum effect η is 60%, and single pixel area A is 100um ², time for exposure t _expfor 1ms, according to formula

μ _e.sat＝ημ _p.sat＝η·I _k.sat·t _exp·A，

I _ksati.e. I ₁be 2252, calculate, full well capacity μ _e.satbe 1351 electronics.

The number of photons μ that the single pixel-by-pixel basis of first-order diffraction spot receives _p.1be 2252, the gray value μ of first-order diffraction spot _y.1be 3700, the background gray value μ of camera five _y.darkbe 150, according to formula

$K=\frac{{\mathrm{\μ}}_{y.k}-{\mathrm{\μ}}_{y.dark}}{{\mathrm{\η\μ}}_{p.k}},$

Entire system yield value K is 2.63DN/e, maximum signal to noise ratio SNR _maxwith the value of dynamic range DR with embodiment 3, photoresponse absolute sensitivity threshold, read the value of noise with embodiment 2.

The schematic execution mode to the invention is described above, and this description does not have restricted, and shown in accompanying drawing is also one of embodiments of the present invention, and actual structure is not limited thereto.So, if those of ordinary skill in the art enlightens by it, when not departing from the invention aim, designing the frame mode similar to this technical scheme and embodiment without creationary, all should protection scope of the present invention be belonged to.

Claims (5)

1. the device of a detected image sensor performance, comprise variable optical attenuation sheet (2) and convergent lens (4), it is characterized in that, it also comprises laser (1), diffraction screen (3) and adjustable loop (5), wherein, described laser (1), variable optical attenuation sheet (2), diffraction screen (3), convergent lens (4) and adjustable loop (5) are fixed in described device successively, the right side of adjustable loop (5) is provided with imageing sensor (6), and the left end of described laser (1) is provided with cable interface.

2. the device of a kind of detected image sensor performance according to claim 1, is characterized in that, the cable interface of the left end of described laser (1) is electrically connected by cable with power supply (11).

3. the device of a kind of detected image sensor performance according to claim 1, it is characterized in that, the left side interface of the interface on the right side of described device and imageing sensor (6) external frame links together, and is formed not by the enclosure space of extraneous light interference.

4. the device of a kind of detected image sensor performance according to claim 2, is characterized in that, the shape of the hole on diffraction screen (3) is rectangle or circle.

5. the device of a kind of detected image sensor performance according to claim 1, is characterized in that, the overall length of described device is 150mm, and maximum gauge is 50mm.