Satellite data Marco Puts THE CONTRACTOR IS ACTING UNDER A FRAMEWORK CONTRACT CONCLUDED WITH THE COMMISSION

Remote Sensing Raster (Matrix) Data Format

What is image processing Enhancing an image or extracting information (features) from image Routines for information extraction from remotely sensed images. …

Image Processing Includes Image quality and statistical evaluation Radiometric correction Geometric correction Image enhancement and sharpening Image classification Pixel based Object-oriented based Accuracy assessment of classification Post-classification and GIS Change detection

Image Quality Errors in remote sensor data: the environmental errors (e.g., atmospheric scattering, cloud), random or systematic malfunction of the remote sensing system (e.g., an uncalibrated detector creates striping), or improper pre-processing of the remote sensor data prior to actual data analysis (e.g., inaccurate analog-to-digital conversion).

Examples

Noise reduction Combined Principle Component Analysis Xie et al. 2004

Noise reduction Gamma Maximum A Posteriori Filter Nezry et al, 1995

Image Statistics Univariate image statistics average, variance, min, max, etc. Multivariate image statistics How much emmitance from more than one band PCA, feature extraction, etc.

Types of radiometric correction Detector error or sensor error (internal error) Atmospheric error (external error) Topographic error (external error)

Atmospheric error

Atmospheric error absolute

Atmospheric error dark frame subtraction

Cloud removal Mean based cloud removal Second highest value algorithm Use mean value of cloudy regions. Second highest value algorithm Detect clouds based on second highest values per row Modified Maximum Averaging Iteratively remove pixels brighter than the average Hybrid

Topographic correction Sun Topographic correction Earth Sat

Geometric correction Geocoding: geographical referencing Registration Image to Map (or Ground Geocorrection) Image to Image Geocorrection Spatial interpolation Intensity interpolation (Resampling)

Image enhancement Resolution adjustment, contrast adjustments (linear and non-linear), band rationing, spatial filtering, fourier transformations, principle component analysis, texture transformations, and image sharpening

Classification Unsupervised Supervised Classes can be hard to identify Information about a class may not be in image

Example ABS: Estimating Crop Area Stats

Example ABS: Estimating Crop Area Stats Classification: Support Vector Machines Gaussian ML classification Multinomial Logistic Regression

Example: Statcan: Crop condition assessment Processing steps: Data Import Reprojection and Clipping Cloud Detection and Removal Computing statistics by region

Reprojection and Clipping

Cloud Detection and Removal

Cloud Detection and Removal

Computing Statistics by Region

Sentinel Toolbox Rich sets of tools for analyzing satellite data http://sentinel.esa.int/web/sentinel