7. Image Processing Part 1

Unit 7 looks at digital images, their display and enhancement, and methods for pre-processing remotely sensed digital images as a first step towards further analysis. We briefly summarise what follows here.

In 7.2, we start by looking at digital images, how they are stored, and the different types of data they may contain. We then move on to the different ways of displaying digital images in 7.3, such as false colour composites. We examine ways of enhancing the display of such imagery. In particular, we look at the idea of a contrast stretch – in other words, accentuating the differences within an image when it is displayed so that it can be visually interpreted. We then move on to look at image pre-processing, the initial steps that are typically taken in many remote sensing operations before meaningful information (such as land cover classes) can be derived from the imagery. In 7.4, we look introduce the main types of image pre-processing and look at cosmetic operations that address problems during data collection and transmission. We then go on in 7.5 to look at radiometric calibration, a key step when attempting to understand reflectance patterns at the Earth’s surface.

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Reading

In preparation for these materials, we recommend that you read through Chapter 3, 4 an 5 of the book by Mather and Koch 2011.

Mather, P.M. and Koch M(2011) Computer Processing of Remotely-Sensed Images – An Introduction, Fourth Edition, Wiley, Chichester

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