PROGRESS MADE
My sole focus area this week was further Look Light traffic light detection cum Traffic Light Color algorithm. The one difference for this week versus previous weeks is that I’ve been using the snipped traffic light images from the CV algorithm output rather than the full scene.
My approach thus far was essentially applying my existing algorithm for each individual color filter (“red”, “green”, “yellow”), getting the number of circles identified and picking the color which resulted in the most circles.
This week, I tested the effectiveness of this algorithm against the outputs of the CV algorithm. Unfortunately, the accuracy was not consistent given new factors that have risen from the CV outputs. This wasn’t all bad news, however, because the detection (or lack thereof) of non-Look Lights was unchanged. The changes in accuracy just affected the classification of the color of the Look Lights.
The biggest issue I faced was with regards to the CV algorithm’s snipping itself. Sometimes the algorithm didn’t not capture all three lights in the traffic light (Problem 1). Sometimes the algorithm cut off a portion of the lights, so they were no longer entirely circular (Problem 2).
I was able to correct accuracy issues with regards to Problem 1, assuming that the illuminated light was preserved in its entirety. I simply modified my algorithm’s thresholding to ensure that just the illuminated light surpasses the threshold. Therefore, the output of this threshold, for all images with the entire illumated light, is basically a colored circle.
Problem 2 has been harder to solve, particularly because there are no longer complete circles. Rather the Hough Transform now looks for curved edges. Unfortunately, reflections of the colored illumination on the traffic light fixture also show up as colored, curved shapes. This is the largest current source of misclassification of color right now.
PROGRESS
Derailed a bit to adjust to new issues in snipped traffic light outputs. Hopeful it will be resolved in the coming days (see plan, below).
DELIVERABLES FOR NEXT WEEK
To address these new problems and leverage the fact that the images reliably only contain (at least portions of) traffic lights, I will see how much more accuracy I can afford by scrapping circle detection altogether and primarily relying on color filtering and thresholding. In other words, this alternative algorithm will still filter on yellow, red, and green in series with thresholding but now use the argmax (argmax of {red, yellow, green}) of the sum of remaining pixels post-thresholding as a means of determining the color.