Objective
The vehicle has to scan and interpret a stereoscopic image, determine the object, how close it is to the vehicle and how best to avoid it.
The computer needs to
- identify the object as different from its surrounding environment from the input received from the optical scanner (camera)
- determine the size of the object
- track and compare the object's size on a given interval
- determine a size change and make a determination based on some logic
Circumstances
The objects are colored 55-gallon drums on a field in the daytime (gray/blue).
Identifying the Object
To "see" the drum, the camera must be able to distinguish it from the background and the computer recognize the object as such. Contrast differences can be used to tell the border of the object.
Determining Object Approach
Once the object is defined, it has to be evaluated. I'm tackling this not with the stereoscopic vantage, but with standard size evaluation. As you approach an object, it seems to become larger in perspective. This can be accomplished by tracking each object in a software instance and comparing the tracked object on a time basis (say every 1/20 second) and calculate a size change. Size would be determined by the percentage of the entire visible frame that the object takes. The object size is compared to the previous sample size and a ratio is generated. If the ratio breaks a predetermined logical threshold, the computer realizes that it is approaching the object too quickly and determines an avoidance maneuver (braking, turning, etc.) Stereoscopic features can be used to improve on the inputs for finer tracking of the object (slightly left/right, approaching at an angle).
Object far away
Object in view, but approaching slowly. Time sequence 00:00:00:00
Time sequence 00:00:00:20
The object gets closer, but not that much closer. Object in frame 1 is 2% of frame. Object in frame 2 is 3% of frame. Ratio is 3/2 = 1.5. It is defined that 0.667 is not significant for a direction change. Car proceedes forward.
Object getting close
Time sequence 00:00:01:00
Time sequence 00:00:01:20
The object gets closer more quickly. Object in frame 1 is 2% of frame. Object in frame 2 is 14% of frame. Ratio is 14/2 = 7.0. It is defined that 5.0 is the catalyst for a direction change. Car brakes to slow, then turns.
Stereoscopic Vision
Comparing two steoscopic visuals will help determine if the car is approaching the object straight-on or at an angle. This may help determine the most effective path for avoiding and circumnavigating the object.
