RESUMO
Spatial heterogeneity of the Rapel reservoir surface waters is analyzed through Landsat images. The image digital counts are used with the aim or developing an aprioristic quantitative sample design.Natural horizontal stratification of the Rapel Reservoir (Central Chile) is produced mainly by suspended solids. The spatial heterogeneity conditions of the reservoir for the Spring 86-Summer 87 period were determined by qualitative analysis and image processing of the MSS Landsat, bands 1 and 3. The space-time variations of the different observed strata obtained with multitemporal image analysis.A random stratified sample design (r.s.s.d) was developed, based on the digital counts statistical analysis. Strata population size as well as the average, variance and sampling size of the digital counts were obtained by the r.s.s.d method.Stratification determined by analysis of satellite images were later correlated with ground data. Though the stratification of the reservoir is constant over time, the shape and size of the strata varys.
RESUMO
Digital image processing represents a relatively new but very dynamic domain. Its importance is still growing due to the rapid development in related computer equipment. In this paper basics concepts are introduced and a survey of problems and methods is presented. Starting with techniques used for the capture of data, it continues with techniques applied to coding new data, image enhancement and pattern recognition. Special attention is given to pattern recognition techniques which provide the basics for classification of data according to established criteria. Finally, two applications are presented; the reconstruction of 3-D volumes from serial cutting and a survey of chlorophyll concentration on Lake Aculeo using remote images obtained by the LANDSAT satellite.