Combined Intensity And Coherent Change Detection In Images

摘要

Described embodiments detect changes in a scene over time using first and second images of the scene. A non-coherent intensity change detector detects large-scale changes between the first image and the second image and generates a large-scale change value for pairs of corresponding pixel locations in the first and second images. If the large-scale change value for a given pair of pixel locations reaches a threshold, a coherent change detector is used to detect small-scale changes between the first and second images. A small-scale change value is generated for the given pairs of pixel locations in the images. A composite change value is generated by combining the large-scale change value and the small-scale change value for each pixel pair. The change thresholds are used to determine whether a change in the scene has occurred over the time period.

主权项

1. A method of detecting changes in a scene over a time period, the method comprising:
using an imaging system to obtain a first image of the scene at a first time and a second image of the scene at a second, different time; using a non-coherent intensity change detector to detect large-scale changes between the first image and the second image; generating a large-scale change value for pairs of corresponding pixel locations in the first and second images; in response to the large-scale change value for each pair of corresponding pixel locations reaching a selected large-scale change threshold, using a coherent change detector to detect small-scale changes between the first image and the second image; generating a small-scale change value for selected ones of the pairs of corresponding pixel locations in the first and second images; and generating a composite change value by combining the large-scale change value and the small-scale change value for each pixel pair, wherein the combining comprises:
determining (i) the large-scale change threshold, (ii) a small-scale change threshold, and (iii) a composite change threshold;combining, based on the determined large-scale change threshold and the determined small-scale change threshold, the large-scale change value and the small-scale change value for each pixel pair; anddetermining, based on the determined composite change threshold, whether a change in the scene has occurred over the time period.