Keywords: Stereophonic image, Biomass, Grass Height
1.Intoroduction
These days, an environmental problem becomes serious. It is important to grasp a change in the plant in the earth scale. The change in the plant is a great influence an environment. Other side, a detailed remote sensing is becoming available because of a satellite's ability improved more high resolution and many channels. Our laboratory has been analyzing satellite data for the estimate biomass in processing. And we have been getting real biomass data by the observation on any places. The methods of observation are biomass measurement and other measurement using car, tower, RC Helicopter. In the biomass measurement, we measure the dry weight, grass height, spectral reflectance in detail on the small cell 1 square meter. In the other measurements, we measure the spectral reflectance and picture on the large area. We want to measure any samples and quickly. But on the biomass measurement, we have to crop grass for a long time. It is heavy work. And we can't crop grass, if we measure it for long run. It needs method to know biomass by the non-contact.
2.Objective
A study of method to estimate biomass using the stereophonic images analysis.
3.Stereophonic Images Measurement System
3D scanner and Stereophonic image are available to measure the height of object by non-contact. 3D scanner can measure correct height and dimension detail. However it needs long time for measuring and it is not easy to move. Other way, the height accuracy using the stereophonic image is lower than 3D scanner. But system is simple and mobility. And it is practicable other observation. Therefore stereophonic image was selected.
Figure 3.1 shows the Stereophonic image measurement system. It has two digital cameras, spectrometer, white board for the reference of spectrometer.
Digital camera is CAMEDIAC-3030ZOOM, OLYMPAS has 3 million pixels CCD and it has non-compress image storage mode (TIFF). It will able to get high-resolution image.
Fig.3.1 Stereophonic image measurement system
Equation 3.1 means the accuracy of height. L is height of camera, is focal length, is pitch of pixel on CCD, B is camera distance.
The accuracy of height is lower 2mm is better because of low grass at Mongolia. So for, camera distance is 1050mm.
Fig.3.2 images
4.Measurement
4.1.Measurement Work Sequence
Biomass measurement work sequence has 5steps. At first, it makes the cells on ground. Cell size is 1 square meter. Measurement target is inside a cell. 2nd, the spectral reflectance and stereo image are gotten, and grass is measured height. 3rd, All grass is cropped. 4th, grass is dried into an oven for 72 hours. At last, measure the dry grass weight.
4.2.Observation Site
In June 2000, we had observation in North America then in august we had observation in Mongolia.
In North America
We visited to Tucson-Arizona, LusCruces-New Mexico, Conza-Kansas and Missoula-Montana. The observation data has a wide variety of environment.
Fig.4.1 Observation site in North America
Fig.4.2 Measuring in North America
