Light source irradiance measurement method, radiation efficiency measurement method and system

Abstract

The invention relates to the field of industrial imaging and illumination, provides a light source parameter measurement method, and particularly relates to a light source irradiance measurement method and system and a radiation efficiency measurement method and system. The basic irradiance is calculated by using the camera, and the basic irradiance is updated and corrected based on the updated exposure time of the camera and the actual charge quantity, so that the accuracy of the finally obtained light source irradiance result is improved, and the deviation of the result is improved to be within + / -1% from + / -10%. And the method is suitable for light sources with various wavelengths, including visible light, ultraviolet light, infrared light and different types of light sources, and has a wider application range compared with a radiation illuminometer in the prior art.

Description

Technical Field

[0001] The present application relates to the field of industrial imaging and lighting, and is a method for measuring light source parameters, and specifically relates to a method for measuring light source radiance, a method for measuring radiation efficiency, and a system. Background Art

[0002] In the field of industrial imaging and lighting, the EMVA1288 standard has already given definitions and methods based on the calculation formula for radiant illumination.

[0003] However, the existing calculation method may differ from the actual test results due to camera or measurement reasons. Moreover, the existing calculation method is only applicable to standard continuous light sources, and does not clearly define pulsed light sources such as xenon lamps with constantly changing energy. Summary of the invention

[0004] In order to solve the above problems, the present application provides a light source radiation illuminance measurement method, a radiation efficiency measurement method and a system. The radiation illuminance data is measured by using a radiation meter, and then the existing radiation illuminance calculation formula is corrected to make the light source radiation illuminance measurement result more accurate.

[0005] In order to achieve the above purpose, the technical solution adopted in the embodiment of the present application is as follows:

[0006] In a first aspect, a method for measuring the radiant illuminance of a light source is provided. The method is applied to an imaging system, wherein the imaging system includes a camera, a light source, and a calibration object. When the camera starts exposure, it sends an on signal to the light source to generate a light source environment and collects an image of the calibration object. The method includes: determining pixel area data, quantum efficiency data, and full well charge data of the camera based on the tag information of the camera, and determining wavelength data based on the tag information of the light source; and determining the basic radiant illuminance of the light source based on the updated exposure time, quantum efficiency data, full well charge data, and wavelength data by the following formula: Where E is the basic radiance of the light source, μ f is the full well charge, h is the Planck constant, c is the speed of light, A is the pixel area, t is the update exposure time, λ is the wavelength, and η(λ) is the quantum efficiency; the initial exposure time of the camera is set, and the initial exposure time is controlled to be reduced in a step-by-step manner, two grayscale change critical points of the image during the reduction process are determined, and the time between the two grayscale change critical points is used as the update integration time, and the basic radiant illuminance is updated based on the update integration time to obtain the radiant illuminance; the initial exposure time is greater than the maximum value of the lighting duration of the light source.

[0007] In some specific implementations, the method also includes: acquiring a calibration plate image based on the updated exposure time, and obtaining a real-time grayscale value of the image, updating the full-well charge based on the deviation between the real-time grayscale value and the saturation grayscale value to obtain an actual charge, and updating the radiation illuminance based on the actual charge.

[0008] In some specific implementations, the method further includes: based on the determined target wavelength range, determining the relative light intensity and the relative irradiance ratio within the wavelength range, and updating the target radiance based on the relative light intensity and the relative irradiance ratio to obtain the radiance of the corresponding wavelength range.

[0009] In some specific implementations, a bandpass filter may be selectively provided in the optical path of the imaging system; determining the relative light intensity within the wavelength range includes: acquiring the corresponding wide band within the spectral range of the light source and determining the transmittance of the bandpass filter, and using the transmittance to characterize the relative light intensity.

[0010] In some specific implementations, the imaging system also includes a radiometer for obtaining a reference radiometric illuminance of the light source; the method also includes: obtaining a corresponding plurality of radiometric illuminances and a corresponding plurality of reference radiometric illuminances based on different update exposure times; performing linear fitting on the plurality of radiometric illuminances and the plurality of reference radiometric illuminances, and updating the radiometric illuminance based on the linear fitting result to obtain a target radiometric illuminance, wherein the target radiometric illuminance is expressed based on the following formula: E0=N*E+M; wherein E0 is the target radiometric illuminance, and N and E are update parameters obtained by linear fitting.

[0011] In a second aspect, a method for measuring the radiation efficiency of a light source is provided, the method comprising: obtaining the radiation energy of the light source through the radiation illuminance of the light source and the light emitting surface area of ​​the light source, and obtaining the electrical energy of the light source through the capacitance of the light source and the output voltage of the light source; the radiation illuminance is obtained based on any of the above methods. The radiation efficiency is determined based on the ratio of the radiation energy to the electrical energy.

[0012] In some specific implementations, the electrical energy of the light source is determined based on the following formula: Q e =0.5*C*V 2 , where C is the capacitance of the light source and V is the output voltage of the light source.

[0013] In a third aspect, an optical system is provided, comprising an imaging system and a measuring system; the imaging system comprises a light source, a camera and a calibration object, the light source is used to provide a light environment for the camera so that the camera can capture an image of the calibration object; the measuring system comprises a processing device and an auxiliary device, the auxiliary device is used to obtain a reference radiant illuminance of the light source, and the processing device is used to execute any of the above-mentioned light source radiant illuminance measurement methods or / and any of the above-mentioned light source radiant efficiency measurement methods.

[0014] In a fourth aspect, an electronic device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes any of the above-mentioned methods for measuring the radiant illuminance of a light source and / or any of the above-mentioned methods for measuring the radiant efficiency of a light source.

[0015] In a fifth aspect, a storage medium is provided, on which a computer program is stored, characterized in that the computer program is executed by a processor to perform any of the above-mentioned methods for measuring the radiant illuminance of a light source and / or any of the above-mentioned methods for measuring the radiant efficiency of a light source.

[0016] In the technical solution provided in the embodiment of the present application, the basic radiant illuminance is calculated by using a camera, and the basic radiant illuminance is updated and corrected based on the updated exposure time of the camera and the actual charge amount, thereby improving the accuracy of the final light source radiant illuminance result, and improving the result deviation from ±10% to within ±1%. This method is applicable to light sources of various wavelengths, including visible light, ultraviolet light, infrared light, and different types of light sources, and has a wider range of applications compared to the use of a radiometer in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] The methods, systems and / or programs in the accompanying drawings will be further described according to exemplary embodiments. These exemplary embodiments will be described in detail with reference to the drawings. These exemplary embodiments are non-limiting exemplary embodiments, wherein example numbers represent similar mechanisms in the various views of the accompanying drawings.

[0019] Figure 1 It is a schematic diagram of the optical system structure provided in an embodiment of the present application.

[0020] Figure 2 It is a flow chart of a method for measuring the radiant illumination of a light source provided in an embodiment of the present application.

[0021] Figure 3-5 These are images of different grayscales in the embodiments of the present application.

[0022] Figure 6 It is a flow chart of a method for measuring radiation efficiency of a light source provided in an embodiment of the present application.

[0023] Figure 7 It is a schematic diagram of the structure of the measuring device provided in the embodiment of the present application.

[0024] Figure 8 It is a schematic diagram of the server structure provided in an embodiment of the present application. DETAILED DESCRIPTION

[0025] In order to better understand the above technical scheme, the technical scheme of the present application is described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present application and the specific features in the embodiments are detailed descriptions of the technical scheme of the present application, rather than limitations on the technical scheme of the present application. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments can be combined with each other.

[0026] In the following detailed description, numerous specific details are set forth by way of example in order to provide a comprehensive understanding of the relevant guidance. However, it will be apparent to those skilled in the art that the present application may be practiced without these details. In other cases, well-known methods, procedures, systems, compositions and / or circuits have been described at a relatively high level, without detail, in order to avoid unnecessarily obscuring aspects of the present application.

[0027] Flowcharts are used in the present application to illustrate the execution process performed by the system according to the embodiment of the present application. It should be clearly understood that the execution process of the flowchart may not be performed in order. On the contrary, these execution processes may be performed in reverse order or simultaneously. In addition, at least one other execution process may be added to the flowchart. One or more execution processes may be deleted from the flowchart.

[0028] Before further describing the embodiments of the present invention in detail, the nouns and terms involved in the embodiments of the present invention are described. The nouns and terms involved in the embodiments of the present invention are subject to the following interpretations.

[0029] (1) In response, it is used to indicate the conditions or states on which the executed operations depend. When the dependent conditions or states are met, one or more operations executed may be in real time or with a set delay. Unless otherwise specified, there is no restriction on the order in which the multiple operations executed are executed.

[0030] (2) Based on is used to indicate the conditions or states on which the executed operations depend. When the dependent conditions or states are met, one or more operations executed may be in real time or have a set delay. Unless otherwise specified, there is no restriction on the order in which the multiple operations executed are executed.

[0031] See also Figure 1 This embodiment provides an optical system 10, including an imaging system and a measuring system; the imaging system includes a light source 11, a camera 12 and a calibration object (not shown), the camera is used to collect images of the calibration object, and the light source is used to provide a light environment for the camera, wherein the calibration object is made of a material with a smooth surface and high reflectivity. The measuring system includes a processing device and an auxiliary device 13, wherein the processing device is a core component, and the radiant illumination value of the light source in the current scene is calculated by obtaining camera parameters and processing images.

[0032] The light source in this embodiment specifically refers to a pulsed light source, including but not limited to a xenon lamp and other light sources having the same light-emitting characteristics.

[0033] The difference from the existing technology is that the EMVA1288 standard has already given the definition and method for the calculation formula of radiant illumination in the existing technology. However, according to the existing calculation method, due to the camera or the actual measurement method, there are differences with the actual test results. Moreover, the existing calculation method is only applicable to standard continuous luminous light sources, and does not clearly define pulsed light sources such as xenon lamps with constantly changing energy.

[0034] Therefore, a method for measuring the irradiance of a light source is provided for the measurement system in the optical system of this embodiment to solve the above technical problems. The measurement method is applied to the processing device, and the processing process can be referred to in Figure 2 The steps shown include:

[0035] Step S21. Determine the pixel area data, quantum efficiency data and full well charge data of the camera based on the tag information of the camera, and determine the wavelength data based on the tag information of the light source; determine the basic radiant illumination of the light source based on the updated exposure time, quantum efficiency data, full well charge data and wavelength data.

[0036] It is common knowledge that the core components of a camera include lenses and digital image sensors. The digital image sensor is essentially a photoelectric converter. Its working principle is to convert a certain number of photons incident on the pixel surface during the exposure integration time into a certain number of electrons, and then convert them into a voltage signal of a certain amplitude through a capacitor that stores these charges. This signal is amplified and quantized and finally becomes the grayscale value of the digital image.

[0037] The area of ​​a pixel is defined as A, and the average number of photons incident on the pixel within a certain exposure integration time is μ p .

[0038] Because μ p It is the number of photons incident on the pixel within a certain exposure integration time. It is equal to the exposure integration time t multiplied by the radiant illumination E and then multiplied by the pixel area A, which is A*E*t, and then divided by the energy of a single photon, which is h*v. E is the radiant illumination on the sensor surface, and the unit of radiant illumination E is W / m2. The above formula is updated as follows: Then the radiant illumination is: Where h is Planck's constant.

[0039] Among them, a portion of the incident photons are absorbed and converted into electrons with the amount of charge received by the camera, that is, the full well charge μ f The ratio of the number of photons converted into charge to the number of incident photons is defined as the quantum efficiency The quantum efficiency is related to the wavelength of the photons irradiating the pixel. Since it is known that the frequency v of light is equal to the speed c of light divided by the wavelength λ, that is: Therefore, based on this quantum efficiency relationship and frequency relationship, the above radiant illumination formula is updated as follows:

[0040]

[0041] This formula is a radiance calculation formula that can be used in the prior art. Through this formula, the radiance corresponding to the light source can be obtained. Therefore, for the light source, as long as the above parameters are obtained, the basic radiance value of the light source can be obtained.

[0042] Among them, the speed of light and Planck's constant are known specific numerical results, the full well charge, pixel area and quantum efficiency are inherent properties of the camera, which can be obtained by determining the camera model and looking up the table, and the camera integration time can be set according to the actual operation process and is also a known value. Therefore, all the above parameters in this embodiment are known and determinable values, and by obtaining the above values, the basic radiant illumination of the current light source at a specific wavelength can be determined.

[0043] Step S22. Set the initial exposure time of the camera, and control the initial exposure time to increase in a step-by-step manner, determine the two grayscale change critical points of the image during the reduction process, and use the time between the two grayscale change critical points as the updated exposure time, and update the initial radiation illuminance based on the update time to obtain the radiation illuminance value.

[0044] In this embodiment, the basic radiant illumination of the light source can be directly obtained by obtaining multiple parameters about the camera in step S21. However, it is worth noting that the light sources in the above scene include continuous light sources and pulsed light sources, and the difference between continuous light sources and pulsed light sources is that the light emission of pulsed light sources is not continuous. It has a light emission cycle and each light emission cycle also includes three stages, namely, a delay stage before light emission, a continuous lighting stage, and a delay stage at the end of light emission. These three stages are determined by the characteristics of the pulsed light source. Therefore, relative to this characteristic of the pulsed light source, it is necessary for the camera to more accurately determine the time of its continuous light emission stage as the exposure time, i.e., the integration time, of the camera.

[0045] Therefore, for the specific pulsed light source scenario in this embodiment, the method in step S21 cannot accurately determine the integration time of the camera, so that the acquired radiance value is greatly different from the actual value.

[0046] In order to solve this technical problem, in this embodiment, step S22 is used to accurately obtain the time distribution of the above three stages of the light source in one cycle, and the basic radiant illuminance obtained in step S21 is updated and corrected according to this time distribution to obtain a more accurate radiant illuminance.

[0047] Specifically, to determine the time of the three stages, it is necessary to first determine the nodes of the three stages, and then accumulate the change time of the nodes as the time of the corresponding stages, which are T1, T2 and T3 respectively. For the determination of the nodes of the three stages, in this embodiment, the grayscale changes collected are used as the marker nodes.

[0048] In this embodiment, the camera is configured with an initial exposure time, and the control relationship between the camera and the light source is that when the camera starts to expose, a start signal is sent to the light source, so that the light source emits light. Among them, the value of the initial exposure time is set to be greater than the maximum value of the lighting duration of the light source in this embodiment. The maximum value of this lighting duration is a known value, which is used to indicate that different pulse light sources have a range of lighting duration values, for example, the lighting duration of a xenon lamp is 5-20us. Therefore, during the measurement process, the initial exposure time is set to be greater than 20us, and in this embodiment, this time is set to 50us.

[0049] Then, the calibration object image is collected in a step-by-step manner to increase the exposure time, and the grayscale change of the image collected during the reduction process and the corresponding two grayscale change critical points are determined. At this time, the time interval between the two critical points is the time interval of the xenon lamp's lighting duration, which is the most accurate camera exposure time, i.e., the integration time.

[0050] It can be understood that when the initial exposure time T0 of the camera is greater than the lighting duration of the light source, it means that the camera exposure stage includes three stages of the light source lighting process. In this stage, because the first two stages do not have the light environment for collecting images, they can have obvious changes in grayscale. The method used in this embodiment is to determine the corresponding stage node by the change of grayscale. Specifically, as the exposure time of the camera decreases, if the change in the grayscale of the collected image is mainly a decrease in the grayscale value, it means that there is a light environment in the image collection scene at this time, which means that the xenon lamp is at the end node of the second stage at this time. The exposure time at this time does not include the third stage of the light source, but only the accumulated time of the first and second stages of the light source, that is, T1+T2. Similarly, the exposure time is reduced again until the grayscale increases, then this node is the end node of the first stage, and the current exposure time T2 is only the accumulated time of the first stage of the light source, that is, T1.

[0051] Through the above process, T1+T2 and T1 can be determined, and in this embodiment, the integral time T2 is determined by the difference between the above two times, that is, the time between two grayscale change critical points is used as the updated integral time.

[0052] The updated integral time obtained here is for step S21 formula Update to get the updated radiance formula: That is, the basic radiance is updated to obtain the radiance.

[0053] The embodiment of the present application can accurately determine the lighting duration of the light source through steps S21 and S22, and calculate the radiant illumination corresponding to the discontinuous light source according to the lighting duration.

[0054] But it is worth noting that in the above process, the camera full well charge μ f is an intrinsic property of the camera and is not necessarily equal to the charge μ required for camera saturation. e Therefore, in order to further accurately determine the irradiance, it is necessary to obtain the accurate actual charge μ e , and replace the full well charge with the actual charge.

[0055] Specifically, in this embodiment, the above measurement process also includes the following steps:

[0056] Step S23. Capture the calibration plate image based on the updated exposure time, and obtain the real-time grayscale value of the image, update the full well charge based on the deviation between the real-time grayscale value and the saturation grayscale value to obtain the actual charge, and update the radiation illuminance based on the actual charge.

[0057] Regarding the determination of the actual charge amount, the full well charge amount μ is calculated based on the deviation between the real-time grayscale value and the saturation grayscale value corresponding to the currently acquired image. f Update to get the corresponding actual charge. The deviation refers to the proportional relationship between the real-time grayscale value and the saturation grayscale value. By obtaining this proportional relationship, the full well charge μ f Update to get the actual charge. The above process is based on the following formula: Where σ represents the real-time grayscale value.

[0058] Through the above process, the actual charge amount of the camera to achieve image acquisition in this optical environment can be determined, and based on the actual charge amount, the basic radiance calculation formula, radiance calculation formula and corresponding basic radiance value and radiance value obtained in step S21 or step S22 are updated to obtain the corresponding update formula and update value. Among them, the process is explained by taking the update of the radiance processed in step S22 as an example. The formula for calculating the radiance value in step S22 is updated as follows:

[0059] In this embodiment, the above method and the above optical system can determine the radiant illumination of the light source in the system, especially the pulsed light source such as a xenon lamp. The radiant illumination value calculation formula obtained by the above method still has certain inaccuracies due to the environment during calculation. Therefore, in order to improve the accuracy of the radiant illumination calculation, a system and method are provided in this embodiment based on the above optical system and radiant illumination measurement method, and the above radiant illumination and radiant illumination calculation formula are updated by obtaining influencing parameters.

[0060] In this embodiment, a radiometer is also provided in the system. The radiometer adopts the existing method to directly obtain the radiometric illumination of the light source as the reference radiometric illumination. The reference radiometric illumination is used to correct the radiometric illumination obtained in the above method.

[0061] Specifically, different camera exposure times and light source brightnesses are set respectively, and a radiometer is used to obtain corresponding radiometric illuminations of multiple reference objects; furthermore, images corresponding to the above-mentioned different exposure times and light source brightnesses are obtained, and the grayscale value of each image is obtained, and multiple radiometric illuminations are calculated based on the grayscale value and the radiometric illumination measurement method in steps S21 to S23.

[0062] Among them, the grayscale value in this embodiment is the maximum grayscale value of the image rather than the mean value. In actual scenarios, there may be problems such as the sensor being tilted due to installation problems and edge occlusion due to interface problems, which may lead to uneven photosensitivity on the camera target surface. Therefore, in this embodiment, the maximum value is taken to represent the degree of photoelectric conversion of the sensor.

[0063] Linear fitting is performed on the multiple acquired radiances and multiple reference radiances, and based on the linear fitting results, the radiance acquired in the process of step S21-step S23 is updated to obtain the target radiance, and the radiance calculation formula is updated to obtain the target radiance calculation formula, which is expressed based on the following formula: E0=N*E+M; wherein E0 is the target radiance, and N and E are update parameters obtained by linear fitting.

[0064] Specifically, the linear fitting update process is described in detail. Different camera exposure times and light source brightness are set, as shown in Table 1. Three sets of integration times are set to 1000us, 2000us, and 3000us, and corresponding to different light source brightness settings. The irradiance of the three light sources is measured by the irradiometer to be 0.28W / m2, 0.176W / m2, and 0.082W / m2 respectively. Under the three sets of parameters, three images are collected by the camera, corresponding to Figure 3-Figure 5 , and take the maximum grayscale σ of each image, which are 168, 201, and 122 respectively.

[0065]

[0066] Table 1. Data mapping table

[0067] According to the data in Table 1, substitute into the formula The corresponding radiance value is calculated according to the method of step S21 to step S23, and the results are shown in Table 2.

[0068] <![CDATA[Irradiance W / m 2 > <![CDATA[Reference irradiance W / m 2 > difference% 0.176 0.184 -4.5 0.28 0.308 -9.8 0.082 0.074 9.2

[0069] Table 2. Result calculation table

[0070] By fitting the above results, the linear formula is obtained: E0=0.849*E+0.0225, where 0.849 and 0.0225 correspond to N value and M value respectively.

[0071] In this embodiment, this method can be used to correct the results of step S21-step S23 to obtain the final target radiant illuminance and radiant illuminance formula. This method and the corresponding radiant illuminance formula can be used to obtain accurate radiant illuminance. The most optimal method is presented in this embodiment.

[0072] As described above, the embodiment of the present application provides a method for measuring the radiant illuminance of a light source, which uses a camera to calculate the basic radiant illuminance, and updates and corrects the basic radiant illuminance based on the camera's updated exposure time and the actual charge amount, thereby improving the accuracy of the final radiant illuminance result of the light source, and improving the deviation of the result from ±10% to within ±1%. This method is applicable to light sources of various wavelengths, including visible light, ultraviolet light, infrared light, and different types of light sources, and has a wider range of uses than the radiometer used in the prior art.

[0073] In this embodiment, the above processing can obtain the radiant illumination of the light source, see Figure 6 , and also provides a method for measuring the radiation efficiency of a light source, comprising the following steps:

[0074] Step S61. Obtain the radiation energy of the light source through the radiation illumination of the light source and the light emitting surface area of ​​the light source, and obtain the electrical energy of the light source through the capacitance of the light source and the output voltage of the light source.

[0075] The radiation illuminance in this embodiment is obtained based on steps S21 to S23.

[0076] Step S62: Determine the radiation efficiency based on the ratio of the radiation energy to the electrical energy.

[0077] In this embodiment, the electric energy of the light source is determined based on the following formula: Q e =0.5*C*V 2 , where C is the capacitance of the light source and V is the output voltage of the light source.

[0078] In this embodiment, since the xenon lamp has a wide spectral range, in order to obtain the radiant illumination corresponding to light sources of different wavelengths for measurement, an optical system and a measurement method are also provided.

[0079] Specifically, a bandpass filter can be optionally configured in this optical system, a wide band in the spectral range of the xenon lamp is taken, and the transmittance ρ of the filter is recorded. According to the spectral range of the xenon lamp and its corresponding relative irradiance value, the irradiance ratio ω of the irradiance value in the target band to the total irradiance value can be calculated.

[0080] The target radiance and target radiance formula obtained in the above process are updated according to the transmittance and irradiance ratio to obtain the band radiance and band radiance formula within this wavelength range, where the band radiance formula is expressed based on the following formula:

[0081]

[0082] In order to better implement the above method, the embodiment of the present application also provides a measuring device, which can be integrated in an electronic device, and the electronic device can be a terminal, a server, etc. Among them, the terminal can be a mobile phone, a tablet computer, a smart Bluetooth device, a laptop, a personal computer, etc.; the server can be a single server or a server cluster composed of multiple servers.

[0083] For example, in this embodiment, the method of the embodiment of the present application will be described in detail by taking the example that the measuring device is specifically integrated into an electronic device.

[0084] For example, Figure 7 As shown, the measuring device 70 may include a radiation illumination measurement module 71 and a radiation efficiency measurement module 72, wherein the radiation illumination measurement module 71 includes:

[0085] The basic radiation illumination unit 711 is used to determine the pixel area data, quantum efficiency data and full well charge data of the camera through the tag information of the camera, and determine the wavelength data based on the tag information of the light source; and determine the basic radiation illumination of the light source based on the updated exposure time, quantum efficiency data, full well charge data and wavelength data.

[0086] The calculation process is configured with a corresponding calculation formula, which is shown as follows: Where E is the basic radiance of the light source, μ f is the full well charge, h is Planck's constant, c is the speed of light, A is the pixel area, t is the update exposure time, λ is the wavelength, and η(λ) is the quantum efficiency.

[0087] The first updating unit 712 is used to set the initial exposure time of the camera, and control the initial exposure time to be reduced in a step-by-step manner, determine two grayscale change critical points of the image during the reduction process, and use the time between the two grayscale change critical points as the update integration time, and update the basic radiant illuminance based on the update integration time to obtain the radiant illuminance.

[0088] Among them, the updated radiation illumination formula is as follows:

[0089] The second updating unit 713 collects the calibration plate image based on the updated exposure time and obtains the real-time grayscale value of the image, updates the full well charge based on the deviation between the real-time grayscale value and the saturation grayscale value to obtain the actual charge, and updates the radiation illumination based on the actual charge.

[0090] The updated irradiance formula is as follows: Where σ represents the grayscale value of the image.

[0091] In this embodiment, the radiant illumination value of the light source can be obtained through the above three modules.

[0092] The radiation efficiency measurement module 72 includes:

[0093] The parameter acquisition unit 721 is used to acquire the radiation energy of the light source through the radiation illumination of the light source and the light emitting surface area of ​​the light source, and acquire the electrical energy of the light source through the capacitance of the light source and the output voltage of the light source.

[0094] The parameters in this embodiment include the radiation energy of the light source and the electrical energy of the light source. The electrical energy of the light source is determined based on the following formula: Q e =0.5*C*V 2 , where C is the capacitance of the light source, and V is the output voltage of the light source. In this embodiment, the electric energy acquisition unit is in electrical communication with the radiation illumination measurement module 71 , and the electric energy acquisition unit is used to acquire the radiation illumination by calling the measurement value obtained by the radiation illumination measurement module 71 .

[0095] The radiation efficiency calculation unit 722 is used to determine the radiation efficiency based on the ratio of the radiation energy and the electrical energy.

[0096] The embodiment of the present application also provides an electronic device, which can be a terminal, a server, etc. The terminal can be a mobile phone, a tablet computer, a smart Bluetooth device, a laptop, a personal computer, etc. The server can be a single server or a server cluster composed of multiple servers, etc.

[0097] In some embodiments, the measuring device may also be integrated into multiple electronic devices. For example, the measuring device may be integrated into multiple servers, and the multiple servers may implement the light source radiance measurement and / or radiation efficiency measurement method of the present application.

[0098] In this embodiment, the electronic device of this embodiment is a server as an example for detailed description, for example, Figure 8 As shown, it shows a schematic diagram of the structure of the server involved in the embodiment of the present application, specifically:

[0099] The server may include one or more processing core processors 801, one or more computer-readable storage media memories 802, a power supply 803, an input module 804, and a communication module 805. Those skilled in the art will appreciate that Figure 8 The server structure shown in the figure does not constitute a limitation on the server, and may include more or fewer components than shown in the figure, or combine certain components, or arrange the components differently. Among them:

[0100] The processor 801 is the control center of the server, and uses various interfaces and lines to connect various parts of the entire server. It executes various functions of the server and processes data by running or executing software programs and / or modules stored in the memory 802, and calling data stored in the memory 802. In some embodiments, the processor 801 may include one or more processing cores; in some embodiments, the processor 801 may integrate an application processor and a modem processor, wherein the application processor mainly processes the operating system, user interface, and application programs, and the modem processor mainly processes wireless communications. It is understandable that the above-mentioned modem processor may not be integrated into the processor 801.

[0101] The memory 802 can be used to store software programs and modules. The processor 801 executes various functional applications and data processing by running the software programs and modules stored in the memory 802. The memory 802 may mainly include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function (such as an image playback function, etc.), etc.; the data storage area may store data created according to the use of the server, etc. In addition, the memory 802 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other volatile solid-state storage devices. Accordingly, the memory 802 may also include a memory controller to provide the processor 801 with access to the memory 802.

[0102] The server also includes a power supply 803 for supplying power to various components. In some embodiments, the power supply 603 can be logically connected to the processor 801 through a power management system, so that the power management system can manage charging, discharging, power consumption, etc. The power supply 803 can also include any components such as one or more DC or AC power supplies, recharging systems, power failure detection circuits, power converters or inverters, and power status indicators.

[0103] The server may further include an input module 804, which may be used to receive input digital or character information and generate keyboard, mouse, joystick, optical or trackball signal input related to user settings and function control.

[0104] The server may also include a communication module 805. In some embodiments, the communication module 805 may include a wireless module. The server may perform short-range wireless transmission through the wireless module of the communication module 805, thereby providing users with wireless broadband Internet access. For example, the communication module 405 may be used to help users send and receive emails, browse web pages, and access streaming media.

[0105] Although not shown, the server may also include a display unit, etc., which will not be described in detail herein. Specifically in this embodiment, the processor 801 in the server will load the executable files corresponding to the processes of one or more application programs into the memory 802 according to the following instructions, and the processor 801 will run the application programs stored in the memory 802, thereby implementing the steps in the methods of the embodiments of the present application.

[0106] The specific implementation of the above operations can be found in the previous embodiments, which will not be described in detail here.

[0107] From the above, it can be seen that light sources suitable for various wavelengths, including visible light, ultraviolet light and infrared light, as well as different types of light sources, have a wider range of uses compared to the radiometer used in the prior art.

[0108] A person of ordinary skill in the art will appreciate that all or part of the steps in the various methods of the above embodiments may be completed by instructions, or by controlling related hardware through instructions. The instructions may be stored in a computer-readable storage medium and loaded and executed by a processor.

[0109] To this end, an embodiment of the present application provides a computer-readable storage medium, in which a plurality of instructions are stored, and the instructions can be loaded by a processor to execute the steps in any one of the light source radiance measurement methods provided in the embodiments of the present application. For example, the instructions can execute the following steps:

[0110] Determine the pixel area data, quantum efficiency data and full well charge data of the camera based on the tag information of the camera, and determine the wavelength data based on the tag information of the light source; determine the basic radiant illumination of the light source based on the updated exposure time, quantum efficiency data, full well charge data and wavelength data;

[0111] Setting an initial exposure time of the camera, and controlling the initial exposure time to decrease in a step-by-step manner, determining two grayscale change critical points of the image during the reduction process, and using the time between the two grayscale change critical points as an update integration time, and updating the basic radiance based on the update integration time to obtain radiance;

[0112] Based on the updated exposure time, a calibration plate image is collected, and a real-time grayscale value of the image is obtained. Based on the deviation of the real-time grayscale value and the saturation grayscale value, the full well charge is updated to obtain the actual charge. Based on the actual charge, the radiation illumination is updated.

[0113] Execute the steps in any one of the light source radiation efficiency measurement methods provided in the embodiments of the present application.

[0114] For example, the instruction may execute the following steps:

[0115] The radiation energy of the light source is obtained through the radiation illumination of the light source and the light emitting surface area of ​​the light source, and the electrical energy of the light source is obtained through the capacitance of the light source and the output voltage of the light source;

[0116] The radiation efficiency is determined based on a ratio of the radiation energy to the electrical energy.

[0117] The storage medium may include: a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, etc.

[0118] According to one aspect of the present application, a computer program product or computer program is provided, the computer program product or computer program including a computer program / instruction, the computer program / instruction being stored in a computer-readable storage medium. A processor of an electronic device reads the computer program / instruction from the computer-readable storage medium, and the processor executes the computer program / instruction, so that the electronic device executes the method provided in various optional implementations of the light source radiance measurement provided in the above-mentioned embodiments.

[0119] Since the instructions stored in the storage medium can execute the steps in any one of the light source radiation illumination measurement methods and / or light source radiation efficiency measurement methods provided in the embodiments of the present application, the beneficial effects that can be achieved in the methods provided in the embodiments of the present application can be achieved. Please refer to the previous embodiments for details and will not be repeated here.

[0120] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can be represented by: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or multiple.

[0121] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0122] The above is a detailed introduction to a light source radiance measurement method, radiation efficiency measurement method, system, device, electronic device, storage medium and program product provided in the embodiments of the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea; at the same time, for technical personnel in this field, according to the ideas of the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A method for measuring the irradiance of a light source, characterized in that: The method is applied to an imaging system, which includes a camera, a light source, and a calibration object. When starting exposure, the camera sends an on signal to the light source to generate a light source environment, and collects an image of the calibration object. The method includes: The pixel area data, quantum efficiency data and full well charge data of the camera are determined based on the tag information of the camera, and the wavelength data is determined based on the tag information of the light source; the basic radiant illumination of the light source is determined by the following formula based on the updated exposure time, quantum efficiency data, full well charge data and wavelength data: Where E is the basic radiance of the light source, μ f is the full well charge, h is Planck's constant, c is the speed of light, A is the pixel area, t is the update exposure time, λ is the wavelength, and η(λ) is the quantum efficiency; The initial exposure time of the camera is set, and the initial exposure time is controlled to be reduced in a step-by-step manner, two grayscale change critical points of the image are determined during the reduction process, and the time between the two grayscale change critical points is used as the update integration time, and the basic radiant illuminance is updated based on the update integration time to obtain the radiant illuminance; the initial exposure time is greater than the maximum value of the lighting duration of the light source.

2. The method for measuring the irradiance of a light source according to claim 1, characterized in that: The method also includes: collecting a calibration plate image based on the updated exposure time and obtaining a real-time grayscale value of the image, updating the full well charge based on a deviation between the real-time grayscale value and the saturation grayscale value to obtain an actual charge, and updating the radiation illumination based on the actual charge.

3. The method for measuring the irradiance of a light source according to claim 2, characterized in that: The method also includes: based on the determined target wavelength range, determining the relative light intensity and the relative irradiance ratio in the wavelength range, and updating the target radiance based on the relative light intensity and the relative irradiance ratio to obtain the radiance of the corresponding wavelength range.

4. The method for measuring the irradiance of a light source according to claim 3, characterized in that: A bandpass filter may be selectively provided in the optical path of the imaging system; the determination of the relative light intensity within the wavelength range includes: acquiring the corresponding wide band within the spectral range of the light source and determining the transmittance of the bandpass filter, and using the transmittance to characterize the relative light intensity.

5. The method for measuring the irradiance of a light source according to any one of claims 2 to 4, characterized in that: The imaging system also includes a radiometer for obtaining a reference radiometric illuminance of the light source; the method also includes: obtaining a corresponding plurality of radiometric illuminances and a corresponding plurality of reference radiometric illuminances based on different update exposure times; performing linear fitting on the plurality of the radiometric illuminances and the plurality of the reference radiometric illuminances, and updating the radiometric illuminance based on the linear fitting result to obtain a target radiometric illuminance, wherein the target radiometric illuminance is expressed based on the following formula: E0=N*E+M; wherein E0 is the target radiometric illuminance, and N and E are update parameters obtained by linear fitting.

6. A method for measuring the radiation efficiency of a light source, characterized in that: The method comprises: The radiation energy of the light source is obtained through the radiation illuminance of the light source and the light emitting surface area of ​​the light source, and the electrical energy of the light source is obtained through the capacitance of the light source and the output voltage of the light source; the radiation illuminance is obtained based on the method described in any one of claims 1-5. The radiation efficiency is determined based on a ratio of the radiation energy to the electrical energy.

7. The method for measuring the radiation efficiency of a light source according to claim 6, characterized in that: The electrical energy of the light source is determined based on the following formula: Q e =0.5*C*V 2 , where C is the capacitance of the light source and V is the output voltage of the light source.

8. An optical system, characterized in that: The system includes an imaging system and a measuring system; the imaging system includes a light source, a camera and a calibration object, the light source is used to provide a light environment for the camera so that the camera can capture an image of the calibration object; the measuring system includes a processing device and an auxiliary device, the auxiliary device is used to obtain a reference radiant illuminance of the light source, and the processing device is used to execute the light source radiant illuminance measurement method described in any one of claims 1-5 or / and the light source radiant efficiency measurement method described in any one of claims 6-7.

9. An electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the method for measuring the radiant illuminance of a light source according to any one of claims 1 to 7 or / and the method for measuring the radiant efficiency of a light source according to any one of claims 6 to 7 is implemented.

10. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for measuring the radiant illumination of a light source according to any one of claims 1 to 7 or / and the method for measuring the radiant efficiency of a light source according to any one of claims 6 to 7 are implemented.

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