Mercury lamp and tungsten lamp combined radiation correction method

Abstract

The invention relates to a mercury lamp and tungsten lamp combined radiation correction method, and belongs to the technical field of correction methods. The problem that the spectral range of tungsten lamp radiation correction is limited in the prior art is solved. The method comprises the following steps of: irradiating an optical system by using a mercury lamp and a tungsten lamp in a dark environment under the conditions that the temperature, the voltage and the mercury vapor pressure are not changed to obtain a mercury lamp characteristic radiation spectrum and a tungsten lamp calibration radiation spectrum, and taking the same wavelength in the mercury lamp characteristic radiation spectrum and the tungsten lamp calibration radiation spectrum as a lap joint wavelength; calculating the ratio of the radiation value of the tungsten lamp overlapping spectral line to the radiation value of the mercury lamp overlapping spectral line, taking the ratio as a scaling coefficient of the radiation value of the mercury lamp, scaling other spectrums in the characteristic radiation spectrum of the mercury lamp according to the scaling coefficient according to a fixed relative proportional relation to obtain a calibration radiation spectrum of the mercury lamp; and performing radiation correction on the optical system by using the mercury lamp calibration radiation spectrum and the tungsten lamp calibration radiation spectrum to obtain a correction result. According to the method, the radiation correction spectral range can be expanded, and the accuracy is higher.

Description

Technical Field

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

[0002] Due to the aerospace measurement environment, it is difficult to perform manual maintenance on on-orbit instruments since launch, and the instruments cannot be inspected and repaired in a timely manner.

[0003] During long-term operation, on-orbit radiation measurement instruments will inevitably have problems such as instrument attenuation, which will cause changes in the instrument's responsiveness and lead to deviations in the measurement data. At this time, a calibration light source is needed to re-calibrate the radiation in order to obtain more accurate data.

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

[0005] However, many radiation measuring instruments currently have a large spectral range. In the part below 350nm, these instruments can no longer perform short-wave radiation correction using only tungsten lamps. Therefore, it is urgent to find a method for radiation correction with a wider spectral range.

[0006] Due to the characteristics of mercury lamps' spontaneous radiation, the frequency of light emitted by mercury lamps is fixed, that is, it only emits some light of fixed wavelength, showing a linear spectrum. Due to its characteristic of emitting fixed wavelengths, mercury lamps are often used for spectral calibration. When mercury lamps are used in normal times, they are disturbed by the objective environment, such as voltage, temperature, mercury vapor pressure changes, etc. The radiation intensity of the characteristic spectrum line of mercury lamps measured experimentally always changes, so mercury lamps are rarely used for radiation calibration. Summary of the invention

[0007] The present invention solves the problem of the limitation of the spectral range of tungsten lamp radiation correction in the prior art and provides a method for combined radiation correction of mercury lamp and tungsten lamp to further expand the spectral range that can be calibrated by radiation.

[0008] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows.

[0009] The method for calibrating the combined radiation of a mercury lamp and a tungsten lamp of the present invention comprises the following steps:

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

[0011] Step 2, then selecting one spectral line from the mercury lamp characteristic radiation spectrum and the tungsten lamp calibration radiation spectrum as the mercury lamp overlap spectrum line and the tungsten lamp overlap spectrum line, wherein the wavelength of the tungsten lamp overlap spectrum line is consistent with that of the mercury lamp overlap spectrum line;

[0012] Step 3: Compare the radiation value of the overlapping spectrum of the tungsten lamp with the radiation value of the overlapping spectrum of the mercury lamp to obtain the scaling factor of the mercury lamp;

[0013] Step 4: scaling the characteristic radiation spectrum of the mercury lamp according to the fixed relative ratio between its spectral lines and the scaling factor of the mercury lamp to obtain a calibrated radiation spectrum of the mercury lamp;

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

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

[0016] Preferably, the mercury lamp overlap spectrum is a mercury lamp primary spectrum.

[0017] The principle of the present invention is:

[0018] Mercury lamps have the characteristic of spontaneous radiation, and the frequency of the emitted light is fixed, that is, it only emits some light of fixed wavelength, which is expressed as a linear spectrum. Moreover, the characteristic spectrum of mercury lamps includes short-wave radiation wavelengths with high signal-to-noise ratio such as 253nm, which can make up for the weakness of low short-wave radiation of tungsten lamps. The radiation intensity of the characteristic spectrum line of mercury lamps is always changing, but although the radiation intensity of the spectrum line of mercury lamps is always changing, under the conditions of constant temperature, voltage, and mercury vapor pressure, the relative radiation intensity between its spectrum lines is proportional.

[0019] By using the relative proportion of the characteristic radiation spectrum of the mercury lamp, the overlapped spectrum of the tungsten lamp and the overlapped spectrum of the mercury lamp are overlapped. By using the radiation characteristics of the tungsten lamp with high stability and good repeatability, the tungsten lamp calibration radiation spectrum is used as the standard, and the characteristic radiation spectrum of the mercury lamp is scaled with the overlap as the standard to make the irradiation values ​​of the two spectra fall under the standard of the tungsten lamp calibration radiation spectrum. The two are combined for radiation correction to achieve the purpose of using the mercury lamp to expand the tungsten lamp radiation calibration spectrum range. In this process, the mercury lamp calibration radiation spectrum is added to the tungsten lamp calibration radiation spectrum to assist in the correction, which increases the accuracy of the radiation correction of the original tungsten lamp calibration radiation spectrum.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The method of the combined radiation correction of the mercury lamp and tungsten lamp of the present invention overlaps the tungsten lamp overlapped spectrum line and the mercury lamp overlapped spectrum line by utilizing the fixed relative proportional relationship of the characteristic radiation spectrum of the mercury lamp (the relative radiation intensity between the spectrum lines of the characteristic radiation spectrum of the mercury lamp has a proportional relationship), so that the characteristic radiation spectrum of the mercury lamp also has the correction function of the tungsten lamp calibration radiation spectrum, and increases the spectral range of the tungsten lamp calibration radiation spectrum, especially the ultraviolet band where the tungsten lamp energy is weaker. After testing, the method of the present invention is used to correct the remote sensing measurement data of the Fengyun-3 solar irradiance spectrometer, so that the correctable spectral range becomes larger, and the attenuation of the spectrometer of up to about 20% in two and a half years is successfully corrected, and the corrected data is better than the results before correction. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the specific implementation modes of the present invention, the drawings required for use in the specific implementation modes will be briefly introduced below. Obviously, the drawings described below are only some specific implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 A flow chart of the method for calibrating the combined radiation of a mercury lamp and a tungsten lamp of the present invention;

[0024] Figure 2 The attenuation of each band of the instrument in the two and a half years before the attenuation correction of the existing Fengyun-3 solar irradiance spectrometer in Example 1;

[0025] Figure 3 The results obtained by calibrating the Fengyun-3 solar irradiance spectrometer using a tungsten lamp in Example 1;

[0026] Figure 4 This is the result obtained by calibrating the Fengyun-3 solar irradiance spectrometer using a mercury lamp and a tungsten lamp in Example 1. DETAILED DESCRIPTION

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

[0028] like Figure 1 As shown, the method for calibrating the combined radiation of a mercury lamp and a tungsten lamp of the present invention comprises the following steps:

[0029] First, in a dark environment, 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 to obtain the characteristic radiation spectrum of the mercury lamp and the calibration radiation spectrum of the tungsten lamp respectively. The same wavelength is taken as the overlap wavelength between the two, and the radiation value of the tungsten lamp at this wavelength is required to be within the appropriate radiation range of the tungsten lamp and have a high signal-to-noise ratio (the wavelength of the overlap spectrum of the tungsten lamp is above 350nm, more preferably above 450nm, and especially preferably above 500nm), and the overlap spectrum of the mercury lamp is the primary spectrum of the mercury lamp. The radiation value of the selected mercury lamp overlapping spectrum line is compared with the radiation value of the tungsten lamp overlapping spectrum line, and the ratio of the radiation value of the tungsten lamp to the mercury lamp at the overlapping spectrum is calculated, and the ratio is used as the scaling factor of the mercury lamp radiation value. Other spectra in the mercury lamp characteristic radiation spectrum are scaled according to this scaling factor according to their fixed relative proportional relationship. At this time, the expanded mercury lamp calibration radiation spectrum is obtained, and the radiation spectrum is jointly corrected by the mercury lamp calibration radiation spectrum and the tungsten lamp calibration radiation spectrum. Usually, the spectral range covered by a single mercury lamp calibration radiation spectrum adopts the mercury lamp calibration radiation spectrum, and the spectral range covered by a single tungsten lamp calibration radiation spectrum adopts the tungsten lamp calibration radiation spectrum. The two overlap and cover the spectral range. Either the mercury lamp calibration radiation spectrum or the tungsten lamp calibration radiation spectrum can be used, which is determined according to actual conditions.

[0030] The mercury lamp and tungsten lamp combined radiation calibration method of the present invention can perform radiation calibration on the instrument in a wider band, especially short waves. In this process, the mercury lamp calibration radiation spectrum is added to the tungsten lamp calibration radiation spectrum to assist in the calibration, thereby increasing the radiation calibration accuracy of the original tungsten lamp calibration radiation spectrum.

[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 Fengyun-3 solar irradiance spectrometer as an example, the attenuation of each band of the instrument was recorded two and a half years before the attenuation correction. The results are as follows: Figure 2 As shown. Figure 2 It can be seen that in the two and a half years before the attenuation correction, as time went on, each wavelength attenuated to varying degrees, with short waves attenuating faster and long waves attenuating slower.

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

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

[0037] After using mercury lamp and tungsten lamp to calibrate attenuation, the attenuation of each band of the instrument in the past two and a half years is as follows: Figure 4 As shown, it can be seen that the attenuation of the shortwave band is well suppressed, the wavelength range of attenuation correction is expanded, and the ultraviolet band with weaker tungsten lamp energy is also corrected.

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

[0039] Obviously, the above embodiments are merely examples for clear explanation, and are not intended to limit the embodiments. For those skilled 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 list all the embodiments here. The obvious changes or modifications derived from them are still within the protection scope of the invention.

Claims

1. A method for combined radiation calibration of mercury lamp and tungsten lamp, characterized in that: Here are the steps: Step 1: First, in a dark environment, under the conditions of constant temperature, voltage, and mercury vapor pressure, use a mercury lamp and a tungsten lamp to irradiate the optical system respectively to obtain a characteristic radiation spectrum of the mercury lamp and a calibration radiation spectrum of the tungsten lamp; Step 2, then selecting one spectral line from the mercury lamp characteristic radiation spectrum and the tungsten lamp calibration radiation spectrum as the mercury lamp overlap spectrum line and the tungsten lamp overlap spectrum line, wherein the wavelength of the tungsten lamp overlap spectrum line is consistent with that of the mercury lamp overlap spectrum line; Step 3: Compare the radiation value of the overlapping spectrum of the tungsten lamp with the radiation value of the overlapping spectrum of the mercury lamp to obtain the scaling factor of the mercury lamp; Step 4: scaling the characteristic radiation spectrum of the mercury lamp according to the fixed relative ratio between its spectral lines and the scaling factor of the mercury lamp to obtain a calibrated radiation spectrum of the mercury lamp; Step 5: Use the mercury lamp calibration radiation spectrum and the tungsten lamp calibration radiation spectrum to perform radiation correction on the optical system to obtain the correction result.

2. The method for combined radiation calibration of mercury lamp and tungsten lamp according to claim 1, characterized in that: The wavelength of the overlapping spectrum line of the tungsten lamp is above 350nm.

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

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

5. The method for combined radiation calibration of mercury lamp and tungsten lamp according to claim 1, characterized in that: The mercury lamp overlap spectrum is the primary spectrum of the mercury lamp.

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