Absolute Radiometric Calibration Technique of Cloud Camera

Gaojun Chi; Jiejun Wang; Mengfan Li; Yadong Hu; Xiangjing Wang; Jin Hong

doi:10.3788/AOS202242.0612001

Acta Optica Sinica, Volume. 42, Issue 6, 0612001(2022)

Absolute Radiometric Calibration Technique of Cloud Camera

Gaojun Chi^1,2,3, Jiejun Wang¹, Mengfan Li^2,3、*, Yadong Hu^2,3, Xiangjing Wang^2,3, and Jin Hong^2,3

¹School of Electronic Engineering and Automation, Guilin University of Electronic Technology, Guilin, Guangxi 541004, China

²Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Sciences, Chinese Academy of Sciences, Hefei, Anhui 230031, China

³Key Laboratory of Optical Calibration and Characterization, Chinese Academy of Sciences, Hefei, Anhui 230031, China

show less

Abstract Get PDF(in Chinese)

Figures & Tables(12)

Fig. 1. Optomechanical structure diagrams of cloud camera. (a) Appearance; (b) three-dimensional explosion model

Download full size

Fig. 2. Schematic of wide-angle imaging optical system

Download full size

Fig. 3. Bayer color filter pattern of CCD detector of cloud camera

Download full size

Fig. 4. Bayer array and pre-filter. (a) Quantum efficiency curves of different color channels of Bayer array; (b) transmittance of pre-filter

Download full size

Fig. 5. Spectral response curves of different channels of CCD detector after adding pre-filter. (a) B channel; (b) R channel

Download full size

Fig. 6. Calibration of absolute radiance responsivity coefficient. (a) Diagram; (b) scene picture

Download full size

Fig. 7. Background noise calibration results of cloud camera. (a) R channel; (b) B channel

Download full size

Fig. 8. Response values of CCD detector R channel under different integral time. (a) LED1 is turned on only; (b) LED2 is turned on only

Download full size

Fig. 9. Response values of CCD detector B channel under different integral time. (a) LED2 is turned on only; (b) LED1 is turned on only

Download full size

Table 1. CCD detector channel response value and equivalent spectral radiance under different brightness of single light source conditions of single light source

View table

Table 1. CCD detector channel response value and equivalent spectral radiance under different brightness of single light source conditions of single light source

Test condition	DN of R channel	DN of B channel	Radiance /(μW·cm^-2·sr^-1·nm^-1)
LED1 off, LED2 max	4.846	197.950	59.146
LED1 off, LED2 typ	2.957	117.248	35.412
LED1 off, LED2 min	1.438	51.061	15.955
LED1 max, LED2 off	108.327	8.912	30.011
LED1 typ, LED2 off	64.917	5.461	17.765
LED1 min, LED2 off	29.969	2.531	8.205

Table 2. Measured and theoretical values of CCD detector channel when LED1 and LED2 are turned on

View table

Table 2. Measured and theoretical values of CCD detector channel when LED1 and LED2 are turned on

Test condition	DN of measured value		DN of theoretical value		Bias /%
Test condition	R channel	B channel	R channel	B channel	R channel	B channel
LED1 max, LED2 max	112.926	206.699	113.173	206.862	-0.218	-0.079
LED1 typ, LED2 typ	67.726	122.177	67.874	122.709	-0.218	-0.434
LED1 min, LED2 min	31.473	55.521	31.407	53.592	0.209	3.474

Table 3. Measurement uncertainty analysis of radiometric calibration
View table
Table 3. Measurement uncertainty analysis of radiometric calibration
Spectral band /nm Uncertainty factor Combineduncertainty /%
Integral sphere ASD measurement Cloud camera
465 2.22 0.63 1.90 2.99
747 1.85 0.62 1.29 2.34

Tools

Get Citation

Copy Citation Text

Gaojun Chi, Jiejun Wang, Mengfan Li, Yadong Hu, Xiangjing Wang, Jin Hong. Absolute Radiometric Calibration Technique of Cloud Camera[J]. Acta Optica Sinica, 2022, 42(6): 0612001

Download Citation

EndNote(RIS)BibTex Plain Text

Set citation alerts for article

Save article for my favorites

Paper Information

Category: Instrumentation, Measurement and Metrology

Received: Jul. 15, 2021

Accepted: Aug. 31, 2021

Published Online: Mar. 8, 2022

The Author Email: Li Mengfan (mfli@aiofm.ac.cn)

DOI:10.3788/AOS202242.0612001

Topics

laser devices and laser physics

Lasers and Laser Optics

Laser physics

laser manufacturing

Instrumentation, Measurement and Metrology

Table 1. CCD detector channel response value and equivalent spectral radiance under different brightness of single light source conditions of single light source

Table 1. CCD detector channel response value and equivalent spectral radiance under different brightness of single light source conditions of single light source

Table 2. Measured and theoretical values of CCD detector channel when LED1 and LED2 are turned on

Table 2. Measured and theoretical values of CCD detector channel when LED1 and LED2 are turned on

Table 3. Measurement uncertainty analysis of radiometric calibration

Table 3. Measurement uncertainty analysis of radiometric calibration