3. DEVELOPMENT OF HIGH SPECTRAL RESOLUTION TECHNIQUES 
One of the earlier type of high spectral resolution system developed in China was the 
Airborne Multispectral Scanner with 19 bands (Xue Yongqi et a 1. 1990). The Scanner has 16 bands 
equally divided in the spectral region of 0.46-l.lPm, and 3 bands in the Short- wave to 
thermal infrared. Since the spectral bands covered the VIS, NIR SWIR and TIR, the scanner is 
conveniened to use for the resouces inventory and environmental monitoring such as landuse 
mapping and disaster monitoring. The VIS/NIR bands are also easy to re- form the VIS/NIR 
channels of Landsat MSS, TM and SPOT HRV bands, and the 3 bands in the 6hort-wave infrared to 
thermal infrared regions are corresponding the band 5, 6 and 7, the system is also used as the 
Landsat and SPOT or other earth resources Satellite, simulator. 
It was found that the shortwave infrared spectral region of 1. 6-2. 5 Pm is very useful to the 
application of minerals and geological exploration. A prototype of airborne imaging 
spectrometer working in the shortwave spectral region was developed specially fo r the 
alteration mapping.lt has 12 spectral bands between 1.6 and 2.5 Pm. By the spectral analysis 
for geological application the spectral bands were selscted as follows: 1.600, 2.035, 2.087, 
2.143, 2.200,2.205, 2.250 2.275, 2.300, 2.330, 2.370 and 2.450 Pm. The bandwidths of above 
channels are between 50-100 nm. Each band has its geological significance (Tong Qingxi et al, 
1993).This system has been used for gold mineral and petroleum and gas exploration in Western 
China. 
A number of studies shows that most diagnostic spectral features for various earth objects 
such as mineral discrimination, detemination of chlorophyll pigment concentration in the water, 
the spectral response of vegetation damaged by the environmental stress request the spectral 
resolution of 10 to 20nm in the Visible/near infrared to the shortwave infrared region(A. F. H. 
Goetz, 1992). In same time, the signal to noise ratio (S/N) of the system is rather important 
for the spectral discrimination. For design of instrument in the VIS and SWIR spectral region ( 
0. 4-3. 0 Pm) the special attension has been paid to the signal to noise ratio. 
The parameters of the system, such as sensitivity, spectral resolution, FOV and IFOV are 
closely related each other. Therefore, the comprehensive consideration is necessary in the 
design of the imaging spectrometer. 
The airborne imaging spectrometer developed by the Shanghai Institute of Technical Physics 
(SITP), Chinese Academy of Sciences consists of a common optico-mechanical scanning system(Fig. 
3-1) and three spectrometers (one for VIS/NIR, one for SWIR and one for TIR). The operational 
parameters of the so called Modular Airborne Imaging Spectrometer (MAIS) can be summarized in 
the following (Xue Yongqi, 1993): 
Fig. 3-1 The optical diagram of the VIS/NIR and SWIR 
region of MAIS