Abbas Alimohammadi - Faculty of Geodesy and Geomatics Eng., K.N. Toosi University of Technology, Tehran, Iran
Ali Ghadiri - Department of Remote Sensing & GIS, Tarbiat Modarres University, Tehran, IRAN

Pixel-based classification approaches rely on the pixel data as the main element and label the pixels individually based on their spectral features. The results of using spectral data of pixels alone are not satisfactory. Experiments have shown that the addition of texture and contextual information can increase the accuracy of classification. The object-oriented approach is mainly based on using important object characteristics such as the shape for classification. This research aims to evaluate the effects of multiresolution segmentation parameters in eCognition software on the accuracy of Object-Oriented Classification of satellite images for extracting different land-use \ cover types. IRS-LISS with three bands from spectral regions of Red, NIR, and MIR and IRS-PAN and IKONOS-PAN images of Tehran urban area were used to perform the land cover classification using the two image classification approaches.The pixel-based image analysis approach using the Maximum likelihood classification algorithm (MLC) showed low accuracy in panchromatic images. Experiments have shown that segmentation results depend on how one defines the parameters and image data in object-oriented image analysis approaches. Scale and color have more effects on the quality of resulting segmentation. Influence of color in keeping local contrast is more important, so that use of lower weights results in the destruction of details in the image. The evaluation of the role of size, shape, and homogeneity of image segments has shown that those segments homogeneous with distinct size and shape characteristics can be extracted and classified with higher accuracy. The object-oriented approach resulted in ۹ to۱۸ percent increases with classification accuracy by using the Nearest Neighbor classification approach. concerning the encouraging results obtained, more detailed research on various aspects of the object-oriented classification approach are recommended.

Pixel-based classification, Object-oriented image analysis, Multiresolution segmentation, Nearest Neighbour classification algorithm, fuzzy logic, eCognition software