Object based image analysis (OBIA) is an alternative to traditional pixel-based analysis that groups pixels into image objects based on characteristics like color, shape, size, and texture before classification. OBIA provides a more robust approach than pixel-based methods alone by incorporating additional contextual information from neighboring pixels to better distinguish between different land cover classes on Earth.

1. WITH EXAMPLES OF
MANY STUDENT THESES
Object based image analysis

2. OUTLINE
 What is object based image analysis (OBIA)
 Why do we need it
 How does it work
 Some examples

3.  First, let’s look at ‘normal’ pixel based image analysis:
 This is based purely on pixels, reflectance values
 For classification, multiple pixels are grouped into classes based
on spectral characteristics
 Classes represent features
on Earth
25/02/2021
Pixel versus Object based Image Analysis, OBIA

4.  Pixel based classification takes into account:
 Color and/or DN value (reflectance)
 Texture (a little)
But nothing else. And sometimes this is not enough, and not good
enough…..
?
Multiple reflectance
values for one class
Green, greener ,
greenest
Pixel versus Object based Image Analysis, OBIA