Disclosure of Invention
The invention aims to overcome the defects in the prior art, provides a parameter testing system for a polarized EMCCD device, and solves the technical problem that the prior art lacks a technical means for objectively evaluating the performance of the parameter of the polarized EMCCD device.
In order to achieve the above purpose, the invention is realized by adopting the following technical scheme:
The invention provides a parameter testing system of a polarized EMCCD device, which comprises a uniform light source, a polarization angle control module, a camera bellows and an upper computer parameter testing system, wherein the camera bellows is used for placing the polarized EMCCD device to be tested, the uniform light source is used for generating uniform light with target wavelength and target light intensity and irradiating the uniform light to the polarization angle control module, the polarization angle control module is used for converting the uniform light into linear polarized light with target polarization angle and irradiating the linear polarized light to the polarized EMCCD device to be tested, and the upper computer parameter testing system is used for being in communication connection with the uniform light source, the polarization angle control module and the polarized EMCCD device to be tested for parameter testing.
Optionally, the uniform light source comprises a halogen tungsten lamp, a monochromator, a light attenuation module and an integrating sphere which are sequentially arranged, wherein the halogen tungsten lamp emits continuous and stable original light, the monochromator separates monochromatic light with target wavelength from the original light, the light attenuation module adjusts the monochromatic light to target light intensity, and uniform light is output through the integrating sphere.
Optionally, the polarization angle control module includes a depolarizer and a polarizer, and the linearly polarized light of the target polarization angle is obtained by comprehensively converting the uniform light through the depolarizer and the polarizer.
Optionally, the parameter testing includes:
the wavelength of the uniform lightAs a control variable, acquiring the current output by a standard detector in the polarization EMCCD device to be detectedSum voltage ofAnd calculate the spectral response of the standard detector:
;
In the formula,For standard detector wavelengthIs used for the calibration of the (c) in the (c),For a standard detector area,Is the integration time;
And drawing a spectral response rate curve according to the wavelength in the target wavelength range and the spectral response rate corresponding to the wavelength, and taking the spectral response rate curve as a parameter test result of the standard detector.
Optionally, the parameter testing includes:
Angle of polarization of linearly polarized lightAs a control variable, acquiring the polarization response of the polarization photosensitive element in the polarization EMCCD device to be detectedAnd calculating the polarization transmittance of the polarized light sensor:
;
In the formula,Spectral response corresponding to the current wavelength of the uniform light;
And carrying out average value calculation according to the preset polarization transmittance corresponding to the plurality of polarization angles to obtain the final polarization transmittance of the polarization photosensitive element.
Optionally, the parameter testing includes:
Angle of polarization of linearly polarized lightAs a control variable, obtaining the maximum value of the pixels of the gray level image of the polarized light sensor in the polarized EMCCD device to be detectedAnd pixel minimumAnd calculating the extinction ratio of the polarized light sensor:
;
And carrying out average value calculation according to extinction ratios corresponding to the preset polarization angles to obtain the final extinction ratio of the polarization photosensitive element.
Optionally, the parameter testing includes:
Turning off a uniform light source, obtaining an acquired image of the polarization EMCCD device to be detected, and marking the acquired image as a background image;
Turning on a uniform light source, obtaining an acquired image of the polarization EMCCD device to be detected, and marking the acquired image as an illumination image;
adjusting the light intensity of the uniform light until the gray value of the white light channel of the illumination image reaches 90% of the maximum gray value, so as to obtain a useful information image;
Calculating the signal-to-noise ratio of the acquired image of the polarization EMCCD device to be detected according to the background image and the useful information image:
;
In the formula,Is the variance of the useful information image and the background image.
Compared with the prior art, the invention has the beneficial effects that:
The invention provides a parameter testing system for a polarized EMCCD device, which is characterized in that uniform light with target wavelength and target light intensity is generated by a uniform light source and irradiated to a polarization angle control module, the uniform light is converted into linear polarized light with target polarization angle by the polarization angle control module and irradiated to the polarized EMCCD device to be tested, and the parameter testing system is in communication connection with the uniform light source, the polarization angle control module and the polarized EMCCD device to be tested. The system can realize the functions of serial port control, image acquisition, parameter test and the like through the upper computer parameter test system, has an intuitive graphical user interface, is convenient for a user to operate and monitor, and can refer to the numerical value of each parameter in real time, thereby realizing objective evaluation on the performance of the integrated polarization EMCCD device parameters.
Detailed Description
The invention is further described below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical aspects of the present invention, and are not intended to limit the scope of the present invention.
Embodiment one:
As shown in FIG. 1, the embodiment of the invention provides a polarization EMCCD device parameter testing system, which comprises a uniform light source, a polarization angle control module, a camera bellows and an upper computer parameter testing system, wherein the camera bellows is used for placing a polarization EMCCD device to be tested, the uniform light source is used for generating uniform light with target wavelength and target light intensity and irradiating the uniform light to the polarization angle control module, the polarization angle control module is used for converting the uniform light into linear polarized light with target polarization angle and irradiating the linear polarized light to the polarization EMCCD device to be tested, and the upper computer parameter testing system is used for being in communication connection with the uniform light source, the polarization angle control module and the polarization EMCCD device to be tested to perform parameter testing.
The polarization EMCCD device to be detected is placed in the camera bellows, so that the influence of surrounding stray light on the polarization EMCCD device is avoided.
The uniform light source is a light source with uniform brightness distribution, the brightness of the light source is uniformly distributed over the whole area, and the phenomena of uneven brightness, uneven hot spots and the like can not occur. Such light sources typically include a plurality of light emitting units, which are arranged and controlled to uniformly emit light. In the embodiment, the uniform light source comprises a halogen tungsten lamp, a monochromator, a light attenuation module and an integrating sphere which are sequentially arranged, wherein the halogen tungsten lamp emits continuous and stable original light, the monochromator separates monochromatic light with target wavelength from the original light, the light attenuation module adjusts the monochromatic light to target light intensity (used for generating low-light conditions required by testing), and the uniform light is output through the integrating sphere.
The polarization angle control module is a device capable of precisely controlling and adjusting the polarization state of light waves. The method can realize accurate regulation and control of the polarization state of the light wave by changing the proportion or angle of the vibration direction of the electric field in the light wave. In particular, in this embodiment, the polarization angle control module includes a depolarizer capable of converting a light wave originally having a specific polarization direction into unpolarized light having vibration intensities uniformly distributed in each direction, and a polarizer capable of converting light originally propagating in each direction into linearly polarized light propagating only in one direction. And comprehensively converting the uniform light through the depolarizer and the polarizer to obtain linearly polarized light with a target polarization angle.
And the upper computer parameter test system operates at the PC end, and in the parameter test system, a parameter interface, such as a parameter calculation interface of image display, corresponding wave band, transmittance, extinction ratio, signal to noise ratio and the like, is written according to a test method of the polarization EMCCD device to be tested.
In order to achieve the above object, the test method of the present invention comprises:
1) According to the figure 1, various hardware devices are correctly connected, the safety of a power supply in each period is ensured, the darkroom is tightly closed, and then an upper computer parameter testing system is opened to start testing.
2) Fig. 2 is a real-time image display module, which can enable a tester to check whether the image transmitted by the lower computer is correct or not at any time and adjust the image in time.
3) The upper computer sends commands to connect with the lower computer, and the working state of the lower computer data acquisition circuit board is controlled through various serial port commands, so that the data acquired by the lower computer is transmitted to the upper computer, and then the data is processed.
4) As shown in fig. 3, the response band test module tests the response rate corresponding to the wavelength of the device in a given wavelength range, and draws a curve of the wavelength and the response to obtain a spectrum response curve and a spectrum range. The method specifically comprises the following steps:
the wavelength of the uniform lightAs a control variable, acquiring the current output by a standard detector in the polarization EMCCD device to be detectedSum voltage ofAnd calculate the spectral response of the standard detector:
;
In the formula,For standard detector wavelengthIs used for the calibration of the (c) in the (c),For a standard detector area,Is the integration time;
And drawing a spectral response rate curve according to the wavelength in the target wavelength range and the corresponding spectral response rate, and taking the spectral response rate curve as a parameter test result of the standard detector. The test results are displayed in real time in fig. 3, which is convenient for the user to check.
5) The transmittance and extinction ratio parameter calculation module is shown in fig. 4. The transmittance parameter is calculated as follows:
Angle of polarization of linearly polarized lightAs a control variable, acquiring the polarization response of a polarization photosensitive element in the polarization EMCCD device to be detectedAnd calculating the polarization transmittance of the polarized light sensor:
;
In the formula,Spectral response corresponding to the current wavelength of the uniform light;
and carrying out average value calculation according to the preset polarization transmittance corresponding to the plurality of polarization angles to obtain the final polarization transmittance of the polarization photosensitive element.
In particular in the present embodiment of the present invention,Obtaining the polarization transmittance of the four polarization direction photosensitizers in the visible light wave band under different incident polarization anglesFinally, the transmittance of the whole chip can be obtained by averaging the four polarization transmittances, and the calculation result is displayed in real time in fig. 4.
6) The process of calculating the extinction ratio parameters as in fig. 4 is as follows:
Angle of polarization of linearly polarized lightAs a control variable, obtaining the maximum value of the pixel of the gray image of the polarized light sensor in the polarized EMCCD device to be detectedAnd pixel minimumAnd calculating extinction ratio of polarized light sensor:
;
And carrying out average value calculation according to extinction ratios corresponding to the preset polarization angles to obtain the final extinction ratio of the polarized light sensor.
In particular, in this embodiment, the extinction ratio of the four-polarization-direction photosensors is calculatedThe four extinction ratios were averaged to give the extinction ratio for the whole chip, and the extinction ratio for each polarization and the extinction ratio for the whole chip can be seen in fig. 4.
7) As shown in fig. 5, the signal-to-noise ratio calculation module specifically includes the following steps:
turning off the uniform light source, obtaining an acquired image of the polarization EMCCD device to be detected, and marking the acquired image as a background image;
turning on a uniform light source to obtain an acquired image of the polarization EMCCD device to be detected, and marking the acquired image as an illumination image;
Adjusting the light intensity of the uniform light until the gray value of the white light channel of the illumination image reaches 90% of the maximum gray value, so as to obtain a useful information image;
Calculating the signal-to-noise ratio of the acquired image of the polarization EMCCD device to be detected according to the background image and the useful information image:
;
In the formula,Is the variance of the useful information image and the background image.
The resulting value of the calculated snr is shown in fig. 5.
The embodiment of the invention designs a set of upper computer parameter testing system based on the testing principle and method of the integrated polarization EMCCD device, the system can debug the working state of the lower computer, the upper computer can watch image data in real time, and the corresponding image data analysis algorithm is written according to the response wave band, the transmittance, the extinction ratio, the signal to noise ratio and other parameter characteristics by combining the testing principle and method, so as to realize the parameter testing interface of the EMCCD polarization integrated device.
The foregoing is merely a preferred embodiment of the present invention, and it should be noted that modifications and variations could be made by those skilled in the art without departing from the technical principles of the present invention, and such modifications and variations should also be regarded as being within the scope of the invention.