Contents
How do you do accuracy assessment in Erdas imagine?
Performing Accuracy Assessment In Erdas Imagine Open up the image ‘watershed_unsup4. img’ that you created in a viewer. Click on the Raster tab –> Classification –> Supervised –> Accuracy Assessment. A new window will open which is the main window for the accuracy assessment tool.
What is the importance of accuracy assessment in image classification?
Accuracy assessment can provide a comparison on a category- by-category basis of classification results vs. known reference data. are the points on the classified image for which actual data categories are known. The reference locations are usually randomly selected.
Is kappa coefficient The best form of error assessment?
So, the higher the kappa coefficient, the more accurate the classification is. Apart from the overall accuracy, the accuracy of class identification needs to be assessed. These cells contain classification errors, i.e. cases when the reference image and the classified image don’t match.
What is Kappa and accuracy?
Accuracy and Kappa Accuracy is the percentage of correctly classifies instances out of all instances. It is a more useful measure to use on problems that have an imbalance in the classes (e.g. 70-30 split for classes 0 and 1 and you can achieve 70% accuracy by predicting all instances are for class 0).
How to save data in accuracy assessment viewer?
Close the text editors, and select FILE | SAVE TABLE in the Accuracy Assessment viewer to save the data in the CellArray, CLOSE the Accuracy Assessment viewer when done. It isn’t that difficult to understand most of the report.
What do you need to know about accuracy assessment?
Accuracy assessment is the procedure used to quantify the reliability of a classified image. The standard accuracy assessment procedure is to construct an “error matrix.” This is a square matrix in which the rows and columns represent the land cover classes from the classified image.
How to close the classifier in accuracy assessment?
Click the Classifier icon from the icon panel. Select ACCURACY ASSESSMENT, once the accuracy assessment viewer opens you can close the classifier menu – it won’t be need anymore. From the accuracy assessment viewer, select FILE | OPEN (or click the Open icon).
How to change the color of the accuracy assessment?
In the accuracy assessment viewer, select VIEW | CHANGE COLORS. Set the color for “Points With No Reference:” to WHITE ( these are the random points that HAVE NOT been assigned a reference value), and “Points With Reference:” to Yellow (these are the random point the HAVE been assigned a reference class value).