Comparison test of manual measure surface reflectance
author: Gavin
2022-01-07
Traditional site reflectance observations mainly rely on manual methods. Portable surface object spectrometers are used to measure the ground surface and the diffuse reflectance reference plate to obtain the ground surface reflectance. This method has the background of time matching, reference plate and manual operation errors. It is necessary to develop a new method of site reflectivity measurement to improve the efficiency of site reflectivity measurement.
This article introduced Optosky, SVC equipment, designed different experiments in Hefei and Dunhuang using the direct method to measure reflectance, and analyzed the data
Principle
The operator uses a portable Fieldspec spectroradiometer (such as Optosky spectrometer) to measure the ground surface of the site and the diffuse reflectance reference plate in turn, and obtain the measured spectra respectively.
This article introduced Optosky, SVC equipment, designed different experiments in Hefei and Dunhuang using the direct method to measure reflectance, and analyzed the data
Principle
The operator uses a portable Fieldspec spectroradiometer (such as Optosky spectrometer) to measure the ground surface of the site and the diffuse reflectance reference plate in turn, and obtain the measured spectra respectively.
Solution
Choose to carry out the comparison test under clear and cloudless weather conditions, the specific steps are as follows:
(1) Preparation work, connect the ATP9110 to the computer, optical fiber and tripod. Install and connect the SVC equipment with the optical fiber and the handle, and install the gray scale target.
(2) Simultaneously start to measure the reflectivity of the site and the reflectivity of the reference plate and record the time to obtain the data.
(3) Software processing and comparison based on the data obtained.
Test result
In the two observation data, the difference between the reflectance measured by ATP9110 and SVC is within 1%, and the maximum is not more than 3%. The measurement data of the two devices have a large deviation. The reason may be that the SVC spectrometer is affected by human factors when measuring the surface (Optosky is equipped with a fixed tripod, the jitter of the handheld SVC, the tilt of the SVC)
Choose to carry out the comparison test under clear and cloudless weather conditions, the specific steps are as follows:
(1) Preparation work, connect the ATP9110 to the computer, optical fiber and tripod. Install and connect the SVC equipment with the optical fiber and the handle, and install the gray scale target.
(2) Simultaneously start to measure the reflectivity of the site and the reflectivity of the reference plate and record the time to obtain the data.
(3) Software processing and comparison based on the data obtained.
Test result
In the two observation data, the difference between the reflectance measured by ATP9110 and SVC is within 1%, and the maximum is not more than 3%. The measurement data of the two devices have a large deviation. The reason may be that the SVC spectrometer is affected by human factors when measuring the surface (Optosky is equipped with a fixed tripod, the jitter of the handheld SVC, the tilt of the SVC)
Conclusion
The results of different experimental data in Hefei and Dunhuang show that Optosky equipped with a fixed device has the same measurement accuracy and calibration function as the previous manual measurement of reflectivity. It can also complete the sky diffuse irradiance and direct solar irradiance measurement
Related products
Using the direct method to measure reflectance, and analyzed the data
Handheld FieldSpec Spectroradiometer:ATP9100
Portable Ground-base Hyperspectral Camera:ATH6010
Related articles
1.Slater PN, Biggar SF5 Holm RG et al. 1987. Reflectance- and radiance-based methods for the in-flight absolute calibration of multispectral sensors [J]. Remote Sens. Environ. 22:11- 37.
2.Frouin R and Gautier C. 1987. CaUbration ofNOAA-7, AVHRR, GOES-5 and GOES-6 VISSR/VAS solar channels [J], Remote Sens. Environ. 22: 103-127.
3.Thome K. 1997. Radiometric calibration of Landsat[J]. Photogrammetric Engineering & Remote Sensing, 63(7):853-858.
4.Thome K, Smith N, Scott K. 2001. Vicarious calibration of MODIS using Railroad Valley Playa[C]// Geoscience and Remote Sensing Symposium, IGARSS '01. IEEE 2001 International. IEEE, 1209-1211 vol.3.
4.Thome KJ. 2001. Absolute radiometric calibration of Landsat 7 ETM+ using the reflectance-based method. Remote Sens. Environ, 78,27-38.
5.Thome K, Czapla-Myers J and Biggar S. 2004. Ground-monitor radiometer system for vicarious calibration [J]. SPIE, 5546: 223-232.
The results of different experimental data in Hefei and Dunhuang show that Optosky equipped with a fixed device has the same measurement accuracy and calibration function as the previous manual measurement of reflectivity. It can also complete the sky diffuse irradiance and direct solar irradiance measurement
Related products
Using the direct method to measure reflectance, and analyzed the data
Handheld FieldSpec Spectroradiometer:ATP9100
Portable Ground-base Hyperspectral Camera:ATH6010
Related articles
1.Slater PN, Biggar SF5 Holm RG et al. 1987. Reflectance- and radiance-based methods for the in-flight absolute calibration of multispectral sensors [J]. Remote Sens. Environ. 22:11- 37.
2.Frouin R and Gautier C. 1987. CaUbration ofNOAA-7, AVHRR, GOES-5 and GOES-6 VISSR/VAS solar channels [J], Remote Sens. Environ. 22: 103-127.
3.Thome K. 1997. Radiometric calibration of Landsat[J]. Photogrammetric Engineering & Remote Sensing, 63(7):853-858.
4.Thome K, Smith N, Scott K. 2001. Vicarious calibration of MODIS using Railroad Valley Playa[C]// Geoscience and Remote Sensing Symposium, IGARSS '01. IEEE 2001 International. IEEE, 1209-1211 vol.3.
4.Thome KJ. 2001. Absolute radiometric calibration of Landsat 7 ETM+ using the reflectance-based method. Remote Sens. Environ, 78,27-38.
5.Thome K, Czapla-Myers J and Biggar S. 2004. Ground-monitor radiometer system for vicarious calibration [J]. SPIE, 5546: 223-232.
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