CN114295565B - Method, apparatus, device and medium for measuring quantum efficiency of image sensor - Google Patents
Method, apparatus, device and medium for measuring quantum efficiency of image sensor Download PDFInfo
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Abstract
The invention provides a method for measuring quantum efficiency of an image sensor, which comprises the following steps: the image sensor receives a continuous spectrum from the light source through the optical fiber panel; the image sensor obtains an image in each interval unit integration time under dark field and exposure conditions respectively to obtain a dark field image group and an exposure image group; subtracting the pixel value of the exposure image group from the pixel value of the dark field image group to obtain a data difference value of unit integration time; acquiring images of the continuous spectrum after filtering by a plurality of specific wavelengths, and positioning the specific positions of the specific wavelengths in the continuous spectrum through an image sensor; fitting to obtain an optical power curve and obtaining an optical power value of a first wavelength through a specific position, a continuous spectrum and a corresponding relation between the continuous spectrum and the optical power; according to the light power value, the first wavelength, the pixel size, the unit integration time, the data difference value and the conversion gain, the quantum efficiency of the image sensor corresponding to the first wavelength is calculated.
Description
Technical Field
The present invention relates to the field of image sensors, and in particular, to a method, apparatus, device, and medium for measuring quantum efficiency of an image sensor.
Background
Quantum efficiency (Quantum Efficiency, QE) is a parameter describing the ability of a pixel to convert photons into electrons and is also an important parameter in evaluating the performance of an image sensor. The higher the quantum efficiency, the stronger the photoelectric conversion capability of the image sensor at the wavelength, and the stronger the weak light expression capability. The accuracy of quantum efficiency is that the smaller the wavelength range of the separated monochromatic light is, namely, the higher the accuracy is, the more continuous the quantum efficiency curve is, and the more accurate the result is.
At present, the main method for testing quantum efficiency is as follows: the uniform light output by the integrating sphere has a continuous spectrum by using a halogen light source, and the light with the required wavelength passes through the different band-pass filters by switching. The wavelength range allowed to pass is large, typically 10nm to 20nm, due to the bandpass filter used. The quantum efficiency curve has a large deviation. Accordingly, there is a need for methods, apparatus, devices and media for measuring the quantum efficiency of an image sensor to ameliorate the above problems.
Disclosure of Invention
The present invention aims to provide a method, a device, an apparatus and a medium for measuring the quantum efficiency of an image sensor, wherein the method is used for precisely measuring the quantum efficiency of the image sensor.
In a first aspect, the present invention provides a method of determining the quantum efficiency of an image sensor, comprising: the image sensor receives a continuous spectrum from the light source through the optical fiber panel; the image sensor obtains an image at each interval unit integration time under dark field and exposure conditions respectively to obtain a dark field image group and an exposure image group; subtracting the pixel value of the exposure image group from the pixel value of the dark field image group to obtain a data difference value of the unit integration time; acquiring images of the continuous spectrum after being filtered by a plurality of specific wavelengths, and positioning the specific positions of the specific wavelengths in the continuous spectrum through the image sensor; fitting to obtain an optical power curve through the specific position, the continuous spectrum and the corresponding relation between the continuous spectrum and the optical power; acquiring an optical power value of a first wavelength through the optical power curve; and calculating the quantum efficiency of the image sensor corresponding to the first wavelength according to the optical power value, the first wavelength, the pixel size, the unit integration time, the data difference value and the conversion gain.
The method for measuring the quantum efficiency of the image sensor has the advantages that the quantum efficiency of any first wavelength can be obtained only by a limited dark field image group and an exposure image group, the quantum efficiency of the image sensor under each wavelength can be comprehensively and continuously displayed, the testing process is simplified, and the testing efficiency is improved.
Optionally, the quantum efficiency QE of the first wavelength satisfies the following formula:
QE＝μ e /μ p
wherein mu e An average number of photoelectrons generated per unit integration time at the first wavelength; mu (mu) p The number of incident photons generated per unit integration time at the first wavelength; the average photoelectron number satisfies the following formula:
μ e ＝Δμ/CG
wherein Δμ is the data difference for the unit integration time; CG is conversion gain. The method has the advantage that the quantum efficiency of the first wavelength is calculated through the average photoelectron number and the average photoelectron number.
Optionally, the method for calculating the conversion gain includes: maintaining the light source unchanged, and adjusting the exposure time of the image sensor; calculating the time domain variance and the average gray value of the pixel value of the region of interest under each exposure time; drawing a graph by taking the average gray value as a horizontal axis and the time domain variance as a vertical axis; and calculating the slope of the linear section of the graph, namely the conversion gain. The beneficial effect is that the conversion gain is calculated by changing the image obtained by the exposure time.
Optionally, the number of incident photons satisfies the following formula:
μ p ＝50.34·A·t exp ·λ·E
wherein E is the optical power value, lambda is the wavelength, A is the pixel size, t exp For the unit integration time. The method has the advantages that the number of incident photons is calculated through the light power value, the wavelength, the pixel size and the unit integration time.
Optionally, subtracting the pixel value of the exposure image group from the pixel value of the dark field image group to obtain a data difference value of unit integration time includes: the image sensor integrates time t per interval unit under dark field condition exp Obtaining a dark field imageObtaining a dark field image group; the image sensor is used for detecting the unit integration time t at intervals under the exposure condition exp Acquiring an exposure image to obtain an exposure image group; the dark field image group at least comprises a first dark field image and two dark field images; the exposure image group at least comprises a first exposure image and a second exposure image; the pixel values are subtracted to obtain a unit integration time t exp The data difference Δμ of (1) satisfies the following formula:
Δμ＝(IMG2-IMG_dark2)-(IMG1-IMG_dark1)
wherein IMG1 is a pixel value of a first exposure image, IMG2 is a pixel value of a second exposure image, img_dark1 is a pixel value of a first dark field image, and img_dark2 is a pixel value of a second dark field image; the acquisition time intervals of the first exposure/dark field image and the second exposure/dark field image are unit integration time t exp . The method has the advantage that the data difference value is calculated through the pixel values of the first dark field image and the two dark field images.
Optionally, the method further comprises: acquiring a bandpass spectrum, wherein the bandpass spectrum is generated by a continuous spectrum emitted by the light source through a dispersion mechanism and an optical filter; the rows or columns of photosensitive elements of the image sensor are parallel to the spectral lines of the continuous spectrum. The method has the advantages that the rows or columns of the photosensitive units of the image sensor are parallel to the spectral lines of the continuous spectrum, so that the wavelengths received by each row or column of the photosensitive units of the image sensor are the same, and error interference is reduced during averaging.
In a second aspect, the present invention provides an apparatus for determining the quantum efficiency of an image sensor for use in the method of any one of the first aspects, the apparatus comprising: the device comprises a photosensitive unit, a light source, a dispersion mechanism, an optical filter, a processing unit and an optical fiber panel; the light source is used for providing light; the dispersion mechanism is used for separating light with different wavelengths in the light source to obtain a continuous spectrum; the photosensitive unit is used for receiving the continuous spectrum from the light source through the optical fiber panel; the image sensor obtains an image at each interval unit integration time under dark field and exposure conditions respectively to obtain a dark field image group and an exposure image group; the processing unit is used for subtracting the pixel value of the exposure image group from the pixel value of the dark field image group to obtain a data difference value of the unit integration time; the optical filter is used for filtering specific wavelengths between the light source and the optical fiber panel, and positioning specific positions of the specific wavelengths in the continuous spectrum through the image sensor; the processing unit is also used for obtaining the optical power curve through fitting through the specific position, the continuous spectrum and the corresponding relation between the continuous spectrum and the optical power; acquiring an optical power value of a first wavelength through the optical power curve; and calculating the quantum efficiency of the image sensor corresponding to the first wavelength according to the optical power value, the first wavelength, the pixel size, the unit integration time, the data difference value and the conversion gain.
Optionally, the device further comprises an adjustment mechanism; the adjusting mechanism is used for adjusting the angle of the optical filter to enable the row or the column of the photosensitive unit of the image sensor to be parallel to the spectral line of the continuous spectrum. The light source has the beneficial effects that when the light rays emitted by the light source pass through the dispersion mechanism, the continuous spectrum is generated; by selecting spectral lines representing different wavelengths from the continuous spectrum as a first wavelength for quantum efficiency analysis, the time for acquiring the first wavelength image is saved; the pixel value of a whole image does not need to be processed, redundant data is reduced, and efficient determination is facilitated.
Optionally, a baffle is disposed between the light source and the dispersion mechanism, and a slit is formed in the baffle, and the slit is used for making the light transmitted through the baffle take the shape of a bar. The parallel light source has the beneficial effects that the light transmitted through the baffle plate is in a strip shape through the slit, so that a parallel light source with good coherence is obtained, and interference is reduced.
Optionally, the device further comprises a luminescent material layer disposed on the optical fiber panel; and a photosensitive unit for absorbing invisible light, converting the invisible light into visible light, and transmitting the visible light to the image sensor. The method has the advantages that the luminous material layer receives invisible light and emits visible light to the photosensitive unit of the image sensor, so that the quantum efficiency of the image sensor at the invisible light wavelength can be calculated conveniently.
Drawings
FIG. 1 is a flow chart of a method for measuring quantum efficiency of an image sensor according to the present invention;
FIG. 2 is a schematic diagram showing a distribution of a continuous spectrum in a pixel unit according to the present invention;
fig. 3 (a) shows a known optical power curve of the light source provided by the present invention;
fig. 3 (b) shows the optical power curve of a specific wavelength provided by the present invention;
FIG. 4 is a graph illustrating the average gray level and the time domain variance according to the present invention;
FIG. 5 is a schematic diagram of an apparatus for measuring quantum efficiency of an image sensor according to the present invention;
fig. 6 is a schematic diagram of an installation structure of an optical fiber panel provided by the invention.
Reference numerals in the drawings:
100. a device; 101. a light source; 102. an optical fiber panel; 103. a photosensitive unit; 104. a processing unit; 105. a storage unit; 106. a baffle; 107. a dispersion mechanism; 108. a light filter; 109. an adjusting mechanism; 310. a layer of luminescent material.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention. Unless otherwise defined, technical or scientific terms used herein should be given the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. As used herein, the word "comprising" and the like means that elements or items preceding the word are included in the element or item listed after the word and equivalents thereof without precluding other elements or items.
Fig. 1 is a flow chart of a method for measuring quantum efficiency of an image sensor according to the present invention.
Aiming at the problems existing in the prior art, the invention provides a method for measuring the quantum efficiency of an image sensor, which comprises the following steps:
s101, the image sensor receives continuous spectrums from a light source through an optical fiber panel;
fig. 2 is a schematic diagram of a continuous spectrum distribution in a pixel unit according to the present invention.
In some embodiments, as shown in FIG. 2, a continuous spectrum of wavelengths from 350nm to 750nm is projected onto the photosensitive cells of the image sensor.
S102, acquiring an image by the image sensor under dark field and exposure conditions at each interval unit integration time to obtain a dark field image group and an exposure image group;
s103, the image sensor subtracts the pixel value of the exposure image group and the pixel value of the dark field image group to obtain a data difference value of the unit integration time;
it should be noted that, the data difference may be executed by fpga\dsp\upper computer software, etc.
In some embodiments, subtracting the pixel values of the set of exposure images from the pixel values of the set of dark field images results in a data difference per unit integration time, comprising:
the image sensor 203 integrates time t per interval unit under dark field conditions exp Acquiring a dark field image to obtain a dark field image group; the image sensor 203 is exposed to light at intervals of the unit integration time t exp Acquiring an exposure image to obtain an exposure image group;
the dark field image group at least comprises a first dark field image and two dark field images; the exposure image group at least comprises a first exposure image and a second exposure image; the pixel values are subtracted to obtain a unit integration time t exp The data difference Δμ of (1) satisfies the following formula:
Δμ＝(IMG2-IMG_dark2)-(IMG1-IMG_dark1)
wherein IMG1 is a pixel value of a first exposure image, IMG2 is a pixel value of a second exposure image, img_dark1 is a pixel value of a first dark field image, and img_dark2 is a pixel value of a second dark field image; the acquisition time intervals of the first exposure/dark field image and the second exposure/dark field image are unit integration time t exp 。
In some embodiments, the difference Δμ1 satisfies the following equation:
Δμ1＝(IMG2-IMG_dark2)-(IMG1-IMG_dark1)
the difference Δμ2 satisfies the following formula:
Δμ2＝(IMG3-IMG_dark3)-(IMG2-IMG_dark2)
wherein IMG1 is the pixel value of the first exposure image, IMG2 is the pixel value of the second exposure image, and IMG3 is the pixel value of the third exposure image; the IMG_dark1 is the pixel value of a first dark field image, the IMG_dark2 is the pixel value of a second dark field image, and the IMG_dark3 is the pixel value of a third dark field image; the acquisition time intervals of the first exposure/dark field image, the second exposure/dark field image and the third exposure/dark field image are all unit integration time t exp . The difference Δμ is obtained by averaging the difference Δμ1 and the difference Δμ2, which is advantageous for reducing errors. Or by comparing the difference Δμ1 with the difference Δμ2, the effect of noise on the data difference is readily analyzed.
In other embodiments, the number of images in the exposure image group and the dark field image group may be any integer greater than or equal to two.
S104, acquiring the continuous spectrum filtered image, wherein the image sensor is positioned to specific positions of a plurality of specific wavelengths in the continuous spectrum;
s105, fitting to obtain an optical power curve through the specific position, the continuous spectrum and the corresponding relation between the continuous spectrum and the optical power; acquiring an optical power value of a first wavelength through the optical power curve;
fig. 3 (a) shows a known optical power curve of the light source 101 provided by the present invention; fig. 3 (b) shows the optical power curve of a specific wavelength provided by the present invention.
In some embodiments, the known optical power curve of the light source 101 is shown in fig. 3 (a). As shown in fig. 3 (b), wavelengths of 450nm, 550nm and 650nm are selected as specific wavelengths, and specific positions in the continuous spectrum of wavelengths of 450nm, 550nm and 650nm are positioned in 16 lines, 35 lines and 52 lines, respectively.
In other embodiments, the specific wavelength may be any wavelength in the continuous spectrum. The specific location may be any location in the continuous spectrum.
In some embodiments, the optical power curve is obtained by a nonlinear regression fitting method from the known optical power curve of the light source 101 and the specific locations in the continuous spectrum of wavelengths of 450nm, 550nm, and 650 nm. And acquiring the optical power value of the first wavelength of 500nm through the optical power curve.
In other embodiments, the first wavelength may be any wavelength in the continuous spectrum. The optical power curve may also be obtained by other fitting methods.
S106, calculating the quantum efficiency of the image sensor at the first wavelength according to the optical power value, the first wavelength, the pixel size, the unit integration time, the data difference value and the conversion gain.
In some embodiments, the quantum efficiency QE of the first wavelength satisfies the following formula:
QE＝μ e /μ p
wherein mu e An average number of photoelectrons generated per unit integration time at the first wavelength; mu (mu) p The number of incident photons generated per unit integration time at the first wavelength;
the average photoelectron number satisfies the following formula:
μ e ＝Δμ/CG
wherein Δμ is the data difference for the unit integration time; CG is conversion gain.
It should be noted that, in some embodiments, the method for calculating the conversion gain includes: keeping the light source 101 unchanged, adjusting the exposure time of the image sensor 203; calculating the time domain variance and the average gray value of the pixel value of the region of interest under each exposure time; drawing a graph by taking the average gray value as a horizontal axis and the time domain variance as a vertical axis; and calculating the slope of the linear section of the graph, namely the conversion gain.
In some embodiments, the exposure time of the image sensor 203 is the unit integration time t exp The method comprises the steps of carrying out a first treatment on the surface of the The region of interest is the entire area of the exposure/dark field image.
In other embodiments, the region of interest is a partial region of an exposure/dark field image.
Fig. 4 is a schematic diagram of a curve of average gray value and time domain variance according to the present invention.
In some embodiments, the average gray value is plotted on the horizontal axis and the time domain variance is plotted on the vertical axis; as shown in fig. 4, the slope of the graph when the average gray value is smaller than 600 is calculated, that is, the conversion gain is calculated.
In some embodiments, the number of incident photons satisfies the following formula:
μ p ＝50.34·A·t exp ·λ·E
wherein E is the optical power value, lambda is the wavelength, A is the pixel size, t exp For the unit integration time.
It is worth noting that in some embodiments, the pixel size is the size of the photosensitive cell. The unit integration time is an acquisition time interval of the first exposure/dark field image and the second exposure/dark field image.
In some embodiments, the method further comprises: acquiring a bandpass spectrum generated by a continuous spectrum emitted by the light source 101 through a dispersion mechanism 107 and a filter 108; the rows or columns of light sensing units 103 of the image sensor 203 are parallel to the spectral lines of the continuous spectrum.
It should be noted that the rows or columns of the photosensitive cells 103 of the image sensor 203 are parallel to the spectral lines of the continuous spectrum, and thus the extending direction of the bandpass spectrum is parallel to the rows or columns of the photosensitive cells 103 of the image sensor 203.
Fig. 5 is a schematic diagram of a device for measuring quantum efficiency of an image sensor according to the present invention.
As shown in fig. 5, the present invention further provides an apparatus 100 for measuring quantum efficiency of an image sensor, for use in the method, the apparatus 100 comprising: a photosensitive unit 103, a light source 101, a dispersion mechanism 107, a filter 108, a processing unit 104, and a fiber panel 102. The light source 101 is configured to provide light. The dispersion mechanism 107 is configured to separate light with different wavelengths in the light source 101, so as to obtain a continuous spectrum. The light sensing unit 103 is configured to receive the continuous spectrum of light from the light source 101 through the optical fiber panel 102. The image sensor 203 obtains an image per unit of integration time under dark field and exposure conditions, respectively, to obtain a dark field image set and an exposure image set. The processing unit 104 is configured to subtract the pixel values of the exposure image group and the pixel values of the dark field image group to obtain the data difference value of the unit integration time. The optical filter 108 is interposed between the light source 101 and the optical fiber panel 102, and is positioned at specific positions of specific wavelengths in the continuous spectrum. The processing unit 104 is further configured to fit the optical power curve comprising the optical power values of the first wavelength to the optical power curve of the known light source 101 at the specific position. The quantum efficiency of the image sensor 203 at the first wavelength is calculated based on the optical power value, the first wavelength, the pixel size, the unit integration time, the data difference value, and the conversion gain.
It is to be appreciated that the processing unit may be a central processing unit (Central Processing Unit, CPU) or a graphics processor (Graphics Processing Unit, GPU), which may also be other general purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), off-the-shelf programmable gate arrays (field programmable gate array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The disclosed methods, steps, and logic blocks in the embodiments of the present invention may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of the method disclosed in connection with the embodiments of the present invention may be embodied directly in hardware for execution by a decoding processor, or in a combination of hardware and software for execution by a decoding processor.
Fig. 6 is a schematic diagram of an installation structure of an optical fiber panel provided by the invention.
In some embodiments, as shown in fig. 6, the fiber optic faceplate 102 is fixedly mounted on the photosensitive unit 103 of the fiber optic faceplate 102. The fiber optic faceplate 102 is formed of an array of optical fibers. The photosensitive units 103 are connected with the optical fibers in a one-to-one correspondence.
In other embodiments, the optical fiber panel 102 and the photosensitive unit 103 of the optical fiber panel 102 may be detachably connected or any other connection manner. One of the photosensitive units 103 may be connected to a plurality of the optical fibers, or one of the optical fibers may be connected to a plurality of the photosensitive units 103.
In some embodiments, the dispersion mechanism 107 may be configured as a prism or other dispersion mechanism 107. The filter 108 may be provided as a bandpass filter 108 or other filter 108. The light source 101 may be configured as a composite light source or other light source.
In some embodiments, the device 100 further comprises an adjustment mechanism 109; the adjustment mechanism 109 is configured to adjust the angle of the optical filter 108 so that the row or column of the photosensitive units 103 of the image sensor 203 is parallel to the spectral line of the continuous spectrum.
In some embodiments, a baffle 106 is disposed between the light source 101 and the dispersion mechanism 107, and a slit is formed in the baffle 106, where the slit is used to make the light beam passing through the baffle 106 take a strip shape.
In some embodiments, the number of the baffles 106 may be two, the two baffles 106 are arranged in parallel, and the light emitted from the light source 101 is emitted through the slit between the two baffles 106.
In other embodiments, the baffle 106 may also be configured as a grating or other optical device such that light transmitted through the optical device is in the form of a stripe.
In some embodiments, the device 100 further comprises a luminescent material layer 110 disposed on the optical fiber panel 102 for absorbing the invisible light, converting the invisible light into visible light, and transmitting the visible light to the photosensitive unit 103 of the image sensor 203.
It is worth noting that silicon-based materials cannot absorb: ultraviolet (UV), deep ultraviolet (Deep Ultra Violet, DUV), extreme ultraviolet (Extreme Ultra Violet, EUV), and lunar rays (X-ray) are invisible light that can cause damage to silicon-based materials. The light is absorbed by the luminescent material, converted into visible light, and photosensitive detection is performed by the image sensor.
In some embodiments, the luminescent material layer 110 is made of a scintillator that absorbs ultraviolet light and emits visible light to the photosensitive cells 103 of the image sensor 203. The quantum efficiency of the photosensitive unit 103 of the image sensor 203 in the ultraviolet band can be obtained, and damage to the photosensitive unit 103 caused by direct ultraviolet radiation is avoided.
In other embodiments, luminescent material layer 110 may also be made of other luminescent materials.
While embodiments of the present invention have been described in detail hereinabove, it will be apparent to those skilled in the art that various modifications and variations can be made to these embodiments. It is to be understood that such modifications and variations are within the scope and spirit of the present invention as set forth in the following claims. Moreover, the invention described herein is capable of other embodiments and of being practiced or of being carried out in various ways.
Claims (10)
1. A method of determining quantum efficiency of an image sensor, comprising:
the image sensor receives a continuous spectrum from the light source through the optical fiber panel;
the image sensor obtains an image at each interval unit integration time under dark field and exposure conditions respectively to obtain a dark field image group and an exposure image group; the unit integration time is the acquisition time interval of the first exposure/dark field image and the second exposure/dark field image;
subtracting the pixel value of the exposure image group from the pixel value of the dark field image group to obtain a data difference value of the unit integration time;
acquiring images of the continuous spectrum after being filtered by a plurality of specific wavelengths, and positioning the specific positions of the specific wavelengths in the continuous spectrum through the image sensor; the specific wavelength is any wavelength in the continuous spectrum; the specific position is any position in the continuous spectrum;
fitting to obtain an optical power curve through the specific position, the continuous spectrum and the corresponding relation between the continuous spectrum and the optical power; acquiring an optical power value of a first wavelength through the optical power curve;
and calculating the quantum efficiency of the image sensor corresponding to the first wavelength according to the optical power value, the first wavelength, the pixel size, the unit integration time, the data difference value and the conversion gain.
2. The method of claim 1, wherein the quantum efficiency QE of the first wavelength satisfies the formula:
QE＝μ e /μ p
wherein mu e An average number of photoelectrons generated per unit integration time at the first wavelength; mu (mu) p The number of incident photons generated per unit integration time at the first wavelength;
the average photoelectron number satisfies the following formula:
μ e ＝Δμ/CG
wherein Δμ is the data difference for the unit integration time; CG is conversion gain.
3. The method according to claim 2, wherein the conversion gain calculation method includes: maintaining the light source unchanged, and adjusting the exposure time of the image sensor; calculating the time domain variance and the average gray value of the pixel value of the region of interest under each exposure time; drawing a graph by taking the average gray value as a horizontal axis and the time domain variance as a vertical axis; and calculating the slope of the linear section of the graph, namely the conversion gain.
4. The method of claim 2, wherein the step of determining the position of the substrate comprises,
the number of incident photons satisfies the following formula:
μ p ＝50.34·A·t exp ·λ·E
wherein E is the optical power value, lambda is the wavelength, A is the pixel size, t exp For the unit integration time.
5. The method of claim 1, wherein subtracting the pixel values of the set of exposure images from the pixel values of the set of dark field images yields a data difference per unit integration time, comprising:
the image sensor integrates time t per interval unit under dark field condition exp Acquiring a dark field image to obtain a dark field image group; the image sensor is used for detecting the unit integration time t at intervals under the exposure condition exp Acquiring an exposure image to obtain an exposure image group;
the dark field image group at least comprises a first dark field image and two dark field images; the exposure image group at least comprises a first exposure image and a second exposure image; the pixel values are subtracted to obtain a unit integration time t exp The data difference Δμ of (1) satisfies the following formula:
Δμ＝(IMG2-IMG_dark2)-(IMG1-IMG_dark1)
wherein IMG1 is the pixel value of the first exposure image, IMG2 is the pixel value of the second exposure image, IMG_dark1 is the pixel value of the first dark field image, and IMG_dark2 is the second dark field imagePixel values of (2); the acquisition time intervals of the first exposure/dark field image and the second exposure/dark field image are unit integration time t exp 。
6. The method according to claim 1, wherein the method further comprises:
acquiring a bandpass spectrum generated by a continuous spectrum of the light source through a dispersion mechanism and an optical filter; the rows or columns of photosensitive elements of the image sensor are parallel to the spectral lines of the continuous spectrum.
7. An apparatus for determining the quantum efficiency of an image sensor for use in the method of any one of claims 1 to 6, the apparatus comprising: the device comprises a photosensitive unit, a light source, a dispersion mechanism, an optical filter, a processing unit and an optical fiber panel;
the light source is used for providing light;
the dispersion mechanism is used for separating light with different wavelengths in the light source to obtain a continuous spectrum;
the photosensitive unit is used for receiving the continuous spectrum from the light source through the optical fiber panel;
the image sensor obtains an image at each interval unit integration time under dark field and exposure conditions respectively to obtain a dark field image group and an exposure image group;
the processing unit is used for subtracting the pixel value of the exposure image group from the pixel value of the dark field image group to obtain a data difference value of the unit integration time;
the optical filter is used for filtering specific wavelengths between the light source and the optical fiber panel, and positioning specific positions of the specific wavelengths in the continuous spectrum through the image sensor;
the processing unit is also used for obtaining the optical power curve through fitting through the specific position, the continuous spectrum and the corresponding relation between the continuous spectrum and the optical power; acquiring an optical power value of a first wavelength through the optical power curve; and calculating the quantum efficiency of the image sensor corresponding to the first wavelength according to the optical power value, the first wavelength, the pixel size, the unit integration time, the data difference value and the conversion gain.
8. The device of claim 7, further comprising an adjustment mechanism;
the adjusting mechanism is used for adjusting the angle of the optical filter to enable the row or the column of the photosensitive unit of the image sensor to be parallel to the spectral line of the continuous spectrum.
9. The apparatus of claim 7, wherein a baffle is disposed between the light source and the dispersion mechanism, and wherein a slit is disposed in the baffle, the slit being configured to cause light transmitted through the baffle to be in a stripe shape.
10. The device of claim 7, further comprising a luminescent material layer disposed on the fiber optic panel for absorbing the invisible light to convert the visible light and transmitting to a light sensing unit of the image sensor.
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