(IJACSA) International Journal of Advanced Computer Science and Applications, Vol. 3, No.8, 2012 18 | Page www.ijacsa.thesai.org Monte Carlo Based Non-Linear Mixture Model of Earth Observation Satellite Imagery Pixel Data Kohei Arai 1 Graduate School of Science and Engineering Saga University Saga City, Japan Abstract— Monte Carlo based non-linear mixel (mixed pixel) model of visible to near infrared radiometer of earth observation satellite imagery is proposed. Through comparative studies with actual real earth observation satellite imagery data between conventional linear mixel model and the proposed non-linear mixel model, it is found that the proposed mixel model represents the pixels in concern much precisely rather than the conventional linear mixel model. Keywords- remote sensing satellite; visible to near infrared radiometer; mixed pixel: mixel; Monte Carlo simulation model. I. INTRODUCTION The pixels in earth observed images which are acquired with Visible to Near Infrared: VNIR sensors onboard remote sensing satellites are, essentially mixed pixels (mixels) which consists of several ground cover materials [1]. Some mixel model is required for analysis such as un-mixing of the mixel in concern [2],[3]. Typical mixel is linear mixing model which is represented by linear combination of several ground cover materials with mixing ratio for each material [4]. It is not always true that the linear mixel model is appropriate [5]. Due to the influences from multiple reflections between the atmosphere and ground, multiple scattering in the atmosphere on the observed radiance from the ground surface, pixel mixture model is essentially non-linear rather than linear. These influence is interpreted as adjacency effect [6].[7]. Method for representation of non-linear mixel model is not so easy. In particular, there is not sophisticated multi reflection model between ground materials. The representation method for non-linear mixel model is based on Monte Carlo Ray Tracing: MCRT model [8]. It is rather easy to designate surface slopes on the ground and multi reflection among trees for MCRT model. The proposed MCRT based non-linear mixel model is applied to real earth observation satellite imagery data of Advanced Spaceborn Thermal Emission and Reflection Radiometer / Visible and Near Infrared Radiometer: ASTER/VNIR onboard on Terra satellite. A comparison of radiance between the conventional linear mixel model and the proposed non-linear mixel model is conducted. As a result, validity of the proposed model is confirmed. The following section describes the proposed non-linear mixel model based on MCRT followed by some experiments for validation of the proposed model. Then, finally, conclusions with some discussions are described. II. PROPOSED NON-LINEAR MIXEL MODEL A. Monte CarloRay Tracing Simulation In order to show a validity of the proposed non-linear mixel model, MCRT simulation study and field experimental study is conducted. MCRT allows simulation of polarization characteristics of sea surface with designated parameters of the atmospheric conditions and sea surface and sea water conditions. Illustrative view of MCRT is shown in Fig.1. Figure 1 Illustrative view of MCRT for the atmosphere and sea water Photon from the sun is input from the top of the atmosphere (the top of the simulation cell). Travel length of the photon is calculated with optical depth of the atmospheric molecule and that of aerosol. There are two components in the atmosphere; molecule and aerosol particles while three are also two components, water and particles; suspended solid and phytoplankton in the ocean. When the photon meets molecule or aerosol (the meeting probability with molecule and aerosol depends on their optical depth), then the photon scattered in accordance with scattering properties of molecule and aerosol. The scattering property is called as phase function 1 . In the visible to near infrared wavelength region, the scattering by molecule is followed by Rayleigh scattering law [10] while that by aerosol is followed by Mie scattering law [10]. Example of phase function of Mie scattering is shown in Fig.2 (a) while that of Rayleigh scattering is shown in Fig.2 (b). 1 http://ejje.weblio.jp/content/phase+function