The world changes all the time, in both big and small ways. Keeping track of those changes can be infuriatingly difficult.
This proves especially true for governmental agencies that are tasked with maintaining accurate databases which detail the state of the community. For instance, Property Appraisal departments are tasked with continually updating their database with property values which are then used for insurance, taxation, and ecological purposes.
When the property on a plot changes significantly, the Property Appraisal department needs to know so they can go and visit the site to reevaluate the property. Identifying which parcels have changed has proved to be very difficult. Historically, this was all done on the honor system: before making significant changes to the property, the owner would file for a permit to upgrade, and then after the work was completed, the appraiser would visit and update the database.
With the advent and availability of aerial imagery, this process can be updated. Inspectors in the office can visually compare an old and a new image to identify changes which may not have been reported to the appraisal office, but this is still a painfully manual process. Automating this process has proved to be challenging.
Recently, Hexagon Geospatial has begun working with several partners in the property appraisal field to update the image change detection process. We set out to create a reliable and simple (at least from a user’s point of view) method for performing automatic image change detection within a parcel of land. The proceeds of this work is a new patent-pending Image Change Detection technique that allows users to automatically compare classification segments generated in property change assessment zones to effectively identify changes that occur over time.
“The property appraisal process can present a host of both business and technical challenges,” said Mladen Stojic, President of Hexagon Geospatial. “Users need automated solutions that are highly effective in helping to accurately predict property changes. By developing this new patent-pending innovation within ERDAS IMAGINE, we have simplified the entire process.”
Delivered with ERDAS IMAGINE, the Property Appraisal workflow allows users to compare imagery captured at different times, and automatically perform a zone-by-zone analysis to determine the extent of change which has occurred in each zone. The results are displayed from the highest probability of change to the lowest, allowing users to visually verify the change and generate a comprehensive report.
This workflow, while designed for property appraisal, has a multitude of uses, from natural resource applications to defense and intelligence.
Watch this demo to see the Automatic Change Detection in action.