Object-Based Image Analysis (OBIA) is a technique used in remote sensing and image processing to extract information from satellite or aerial imagery at the object level. It is an alternative approach to traditional pixel-based analysis, which treats each pixel as an independent unit of analysis. In OBIA, the basic building blocks of analysis are not individual pixels but meaningful image objects, which can be defined as homogeneous regions of pixels that share similar characteristics such as color, texture, or shape. These objects are derived through a process known as image segmentation, where the image is partitioned into meaningful and homogeneous regions based on predefined criteria.
Once the image objects are identified, OBIA methods employ a combination of spatial, spectral, and contextual information to extract valuable information from the imagery. This can involve classification, feature extraction, change detection, or other analysis techniques. OBIA allows for a more comprehensive analysis by considering the relationships and interactions between objects, which can provide a better understanding of the landscape and improve the accuracy of the results.