A method for combined radiation correction of mercury lamps and tungsten lamps

Abstract

The present invention relates to a method for combined radiation correction of a mercury lamp and a tungsten lamp, belonging to the technical field of correction methods. It solves the problem of the limitation of the spectral range of tungsten lamp radiation correction in the prior art. In the method of the present invention, first in a dark environment and under the conditions that the temperature, voltage, and mercury vapor pressure remain unchanged, the optical system is irradiated with a mercury lamp and a tungsten lamp respectively to obtain the characteristic radiation spectrum of the mercury lamp and the calibration radiation spectrum of the tungsten lamp. The same wavelength in the two is taken as the overlapping wavelength, and the ratio of the radiation value of the overlapping spectral line of the tungsten lamp to the radiation value of the overlapping spectral line of the mercury lamp is calculated. This ratio is used as the scaling coefficient of the radiation value of the mercury lamp. Other spectra in the characteristic radiation spectrum of the mercury lamp are scaled according to this scaling coefficient according to their fixed relative proportion relationship to obtain the calibration radiation spectrum of the mercury lamp. The radiation correction of the optical system is carried out by using the calibration radiation spectrum of the mercury lamp and the calibration radiation spectrum of the tungsten lamp to obtain the correction result. This method can expand the spectral range of radiation correction and has higher accuracy at the same time.

Description

Technical Field

[0001] The present invention belongs to the technical field of calibration methods, and particularly relates to a method for combined radiation calibration of a mercury lamp and a tungsten lamp. Background Art

[0002] Due to the space measurement environment, it is difficult to perform manual maintenance on on-orbit instruments since their launch, and it is impossible to perform timely maintenance on the instruments.

[0003] During the long-term operation of on-orbit radiation measurement instruments, problems such as instrument attenuation will inevitably occur, which will change the instrument responsivity and cause deviations in measurement data. At this time, a calibration light source is needed to perform radiation calibration on it again to obtain more accurate data.

[0004] Tungsten lamps are usually selected for on-orbit radiation calibration. The radiation value of tungsten lamps has high stability and good repeatability, and they are often used as calibration light sources and widely used in the radiation calibration of spectral instruments. However, when using tungsten lamps for radiation calibration, due to the limited spectral range of tungsten lamps suitable for radiation calibration, the radiation energy in the part below 350 nm is very weak, resulting in a low signal-to-noise ratio, and these low-radiation bands cannot participate in radiation calibration.

[0005] However, at present, many radiation measurement instruments have a large spectral range. In the part below 350 nm, these instruments cannot perform short-wave radiation calibration only with tungsten lamps. Therefore, there is an urgent need to find a method with a wider spectral range for radiation calibration.

[0006] Due to the spontaneous emission characteristics of mercury lamps, the light frequency emitted by mercury lamps is a fixed value, that is, only some lights with fixed wavelengths are emitted, showing a linear spectrum. Because of its characteristic of emitting fixed wavelengths, mercury lamps are often used for spectral calibration. When using mercury lamps usually, affected by objective environmental interferences such as voltage, temperature, and mercury vapor pressure changes, the radiation intensity of the characteristic spectral lines of mercury lamps measured in experiments always changes. Therefore, mercury lamps are hardly used for radiation calibration. Summary of the Invention

[0007] In order to solve the problem of the limited spectral range of tungsten lamp radiation calibration in the prior art, the present invention provides a method for combined radiation calibration of a mercury lamp and a tungsten lamp to further expand the spectral range that can be radiatively calibrated.

[0008] The technical solutions adopted by the present invention to solve the above technical problems are as follows.

[0009] The method for combined radiation calibration of a mercury lamp and a tungsten lamp of the present invention is as follows:

[0010] Step 1: First, irradiate the optical system with a mercury lamp and a tungsten lamp respectively in a dark environment and under the conditions that the temperature, voltage, and mercury vapor pressure remain unchanged to obtain the characteristic radiation spectrum of the mercury lamp and the calibration radiation spectrum of the tungsten lamp;

[0011] Step 2: Then, select a spectral line from the characteristic radiation spectrum of the mercury lamp and the calibration radiation spectrum of the tungsten lamp as the mercury lamp overlapping spectral line and the tungsten lamp overlapping spectral line, and the wavelengths of the tungsten lamp overlapping spectral line and the mercury lamp overlapping spectral line are the same;

[0012] Step 3: Take the ratio of the radiation value of the tungsten lamp overlapping spectral line to the radiation value of the mercury lamp overlapping spectral line to obtain the scaling factor of the mercury lamp;

[0013] Step 4: Scale the characteristic radiation spectrum of the mercury lamp according to the fixed relative ratio relationship between its spectral lines by the scaling factor of the mercury lamp to obtain the calibration radiation spectrum of the mercury lamp;

[0014] Step 5: Use the calibration radiation spectrum of the mercury lamp and the calibration radiation spectrum of the tungsten lamp to perform radiation correction on the optical system to obtain the correction result.

[0015] Preferably, the wavelength of the tungsten lamp overlapping spectral line is above 350 nm, more preferably above 450 nm, and particularly preferably above 500 nm.

[0016] Preferably, the mercury lamp overlapping spectral line is the first-order spectrum of the mercury lamp.

[0017] The principle of the present invention is as follows:

[0018] The mercury lamp has the characteristic of spontaneous emission, and the emitted light frequency is a fixed value, that is, it only emits some lights with fixed wavelengths, showing a linear spectrum. Moreover, the characteristic spectrum of the mercury lamp includes short-wave radiation wavelengths with high signal-to-noise ratios such as 253 nm, which can make up for the weakness of the low short-wave radiation of the tungsten lamp. Although the radiation intensity of the characteristic spectral lines of the mercury lamp always changes, under the conditions of constant temperature, voltage, and mercury vapor pressure, the relative radiation intensities between its spectral lines have a proportional relationship.

[0019] Utilize the relative proportional relationship of the characteristic radiation spectrum of the mercury lamp to overlap the tungsten lamp overlapping spectral line and the mercury lamp overlapping spectral line. Borrow the radiation characteristics of the tungsten lamp with high stability and good repeatability. Take the calibration radiation spectrum of the tungsten lamp as the standard, and scale the radiation value of the characteristic radiation spectrum of the mercury lamp with the overlapping point as the standard, so that the spectral irradiation values of both are under the standard of the calibration radiation spectrum of the tungsten lamp. The two are jointly used for radiation correction to achieve the purpose of borrowing the mercury lamp to expand the radiation calibration spectral range of the tungsten lamp. And in this process, the calibration radiation spectrum of the mercury lamp is added to the calibration radiation spectrum of the tungsten lamp to assist in the correction, increasing the radiation correction accuracy of the original calibration radiation spectrum of the tungsten lamp.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] The method for combined radiation correction of mercury lamp and tungsten lamp of the present invention utilizes the fixed relative proportion relationship of the characteristic radiation spectrum of the mercury lamp (there is a proportional relationship between the relative radiation intensities of the spectral lines of the characteristic radiation spectrum of the mercury lamp), overlaps the overlapping spectral lines of the tungsten lamp and the mercury lamp, so that the characteristic radiation spectrum of the mercury lamp also has the correction function of the calibration radiation spectrum of the tungsten lamp, increasing the spectral range of the calibration radiation spectrum of the tungsten lamp, especially the ultraviolet band where the energy of the tungsten lamp is weak. After testing, using the method of the present invention to correct the remote sensing measurement data of the FY-3 solar irradiance spectrometer makes the spectral range that can be corrected larger, successfully corrects the attenuation of up to about 20% in two and a half years of the spectrometer, and the corrected data is better than the result before correction. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the specific embodiments of the present invention, the following will briefly introduce the drawings required to be used in the specific embodiments. Obviously, the drawings described below are only some specific embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0023] Figure 1 It is a flowchart of the method for combined radiation correction of mercury lamp and tungsten lamp of the present invention;

[0024] Figure 2 It shows the attenuation situation of each band of the instrument in two and a half years before the attenuation correction of the existing FY-3 solar irradiance spectrometer in Embodiment 1;

[0025] Figure 3 It shows the result obtained by using the tungsten lamp to correct the FY-3 solar irradiance spectrometer in Embodiment 1;

[0026] Figure 4 It shows the result obtained by using the combined correction of mercury lamp and tungsten lamp to correct the FY-3 solar irradiance spectrometer in Embodiment 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] In order to further understand the present invention, the following describes the preferred implementation embodiments of the present invention. However, it should be understood that these descriptions are only for further explaining the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0028] As Figure 1 shown, the method for combined radiation correction of mercury lamp and tungsten lamp of the present invention is as follows:

[0029] Prior to the dark environment, and under the conditions of constant temperature, voltage, and mercury vapor pressure, the optical system is irradiated with a mercury lamp and a tungsten lamp respectively, and the characteristic radiation spectrum of the mercury lamp and the calibration radiation spectrum of the tungsten lamp are obtained respectively. Take the same wavelength between the two as the overlapping wavelength, and it is required that the radiation value of the tungsten lamp at this wavelength is within the appropriate radiation range of the tungsten lamp and has a high signal-to-noise ratio (the wavelength of the tungsten lamp overlapping spectral line is above 350 nm, more preferably above 450 nm, and particularly preferably above 500 nm), and the mercury lamp overlapping spectral line is the first-order spectrum of the mercury lamp. Compare the radiation value of the selected mercury lamp overlapping spectral line with the radiation value of the tungsten lamp overlapping spectral line, calculate the ratio of the radiation values of the tungsten lamp and the mercury lamp at the overlapping spectrum, and use this ratio as the scaling coefficient of the mercury lamp radiation value. Other spectra in the characteristic radiation spectrum of the mercury lamp are scaled according to this scaling coefficient according to their fixed relative proportion relationship. At this time, the expanded calibration radiation spectrum of the mercury lamp is obtained, and the radiation spectrum is corrected jointly using the calibration radiation spectrum of the mercury lamp and the calibration radiation spectrum of the tungsten lamp. Generally, the calibration radiation spectrum of the mercury lamp is used for the spectral range covered by the calibration radiation spectrum of the mercury lamp alone, and the calibration radiation spectrum of the tungsten lamp is used for the spectral range covered by the calibration radiation spectrum of the tungsten lamp alone. For the overlapping spectral range, either the calibration radiation spectrum of the mercury lamp or the calibration radiation spectrum of the tungsten lamp can be used, which is determined according to the actual situation specifically.

[0030] The method for joint radiation correction of mercury lamp and tungsten lamp of the present invention can perform radiation calibration on the instrument for a wider wavelength band, especially for short wavelengths. And in this process, the calibration radiation spectrum of the mercury lamp is added to the calibration radiation spectrum of the tungsten lamp to assist in calibration, increasing the radiation calibration accuracy of the original calibration radiation spectrum of the tungsten lamp.

[0031] The terms used in the present invention generally have the meanings commonly understood by those of ordinary skill in the art, unless otherwise specified.

[0032] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below in conjunction with embodiments and comparative examples.

[0033] Example 1

[0034] Taking the remote sensing measurement data of the FY-3 solar irradiance spectrometer as an example, record the attenuation of each band of the instrument during the two and a half years before attenuation correction. The results are as Figure 2 shown. It can be seen from Figure 2 that during the two and a half years before attenuation correction, with the passage of time, the attenuation occurred to varying degrees at each wavelength, among which the short wavelength attenuated faster and the long wavelength attenuated slower.

[0035] Taking the solar irradiance measurement data corresponding to the mercury lamp and tungsten lamp spectral lines in the remote sensing measurement data of the FY-3 solar irradiance spectrometer as an example.

[0036] The effect of instrument attenuation correction only using the tungsten lamp radiation correction method is as Figure 3As shown, it can be seen that after using a tungsten lamp for attenuation correction for two and a half years, the attenuation in the medium and long wavelength bands has been suppressed, but the attenuation in the short wavelength part cannot be corrected.

[0037] The attenuation of each wavelength band of the instrument during two and a half years after using a mercury lamp and a tungsten lamp for combined attenuation correction is as Figure 4 shown. It can be seen that the attenuation in the short wavelength band has been well suppressed, expanding the wavelength range of attenuation correction, so that the ultraviolet wavelength band with weak tungsten lamp energy has also been corrected.

[0038] Figure 4 There is still some attenuation that has not been corrected. This is because in the structure of this instrument, there are two glass sheets in front of the optical system that can be irradiated by the mercury lamp and the tungsten lamp. These two glass sheets still have attenuation, but this part cannot be irradiated by the mercury lamp and the tungsten lamp, so the attenuation correction cannot be carried out. It can be seen from the results that the method of the present invention has successfully corrected up to about 20% of the attenuation of the instrument during two and a half years. The results show that the attenuation of the instrument can be effectively corrected by using this method.

[0039] Obviously, the above embodiments are only examples given for clear illustration and are not limitations on the embodiments. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A method for joint radiation correction of mercury lamps and tungsten lamps, characterized in that, The steps are as follows: Step 1: First, irradiate the optical system with a mercury lamp and a tungsten lamp respectively in a dark environment under the conditions of constant temperature, voltage, and mercury vapor pressure to obtain the characteristic radiation spectrum of the mercury lamp and the calibration radiation spectrum of the tungsten lamp; Step 2: Then, select a spectral line from the characteristic radiation spectrum of the mercury lamp and the calibration radiation spectrum of the tungsten lamp as the mercury lamp overlapping spectral line and the tungsten lamp overlapping spectral line respectively, and the wavelengths of the tungsten lamp overlapping spectral line and the mercury lamp overlapping spectral line are the same; Step 3: Compare the radiation value of the tungsten lamp overlapping spectral line with the radiation value of the mercury lamp overlapping spectral line to obtain the scaling coefficient of the mercury lamp; Step 4: After scaling the characteristic radiation spectrum of the mercury lamp according to the fixed relative proportional relationship between its spectral lines by the scaling coefficient of the mercury lamp, obtain the calibration radiation spectrum of the mercury lamp; Step 5: Perform radiation correction on the optical system using the calibration radiation spectrum of the mercury lamp and the calibration radiation spectrum of the tungsten lamp to obtain the correction result.

2. The method for combined radiation correction of mercury lamps and tungsten lamps according to claim 1, wherein The wavelength of the tungsten lamp overlapping spectral line is above 350 nm.

3. The method for combined radiation correction of mercury lamp and tungsten lamp according to claim 2, characterized in that, The wavelength of the tungsten lamp overlapping spectral line is above 450 nm.

4. The method for combined radiation correction of mercury lamp and tungsten lamp according to claim 3, characterized in that, The wavelength of the tungsten lamp overlapping spectral line is above 500 nm.

5. The method for combined radiation correction of mercury lamps and tungsten lamps according to claim 1, wherein The mercury lamp overlapping spectral line is the first-order spectrum of the mercury lamp.

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