Progress Made
My sole focus area this week was further Look Light traffic light detection cum Traffic Light Color algorithm. This image processing / pattern recognition based algorithm is based on the Hough transform, which returns the positions of circles of radii within a specified range as found within an input image.
My work was broken up into the following areas:
- Light Exposure (concern for Look Light and State Detection)
- A holdover problem from last week was with overexposed images in lower light settings (i.e. some of my validation photos taken at dusk). In these photos, the lights were white in color towards the center of the light, therefore not conserved when passed a red, yellow, and/or green filter. My first stab at fixing this was to regularize the maximum RGB intensity of each photo through some simple pixelwise arithmetic with a reference intensity. This technique, after experimenting with various references intensities, yielded marginal improvement. Similarly, converting to HSV and doing something similar did not yield further significant improvements. Adding a white filter a la the red, yellow, and green filters did not yield any further improvement and actually worsened the accuracy for some photos.
I have not yet tested using a threshold of RGB or HSV intensity in combination with any techniques above, so I will be testing this strategy next week.
- A holdover problem from last week was with overexposed images in lower light settings (i.e. some of my validation photos taken at dusk). In these photos, the lights were white in color towards the center of the light, therefore not conserved when passed a red, yellow, and/or green filter. My first stab at fixing this was to regularize the maximum RGB intensity of each photo through some simple pixelwise arithmetic with a reference intensity. This technique, after experimenting with various references intensities, yielded marginal improvement. Similarly, converting to HSV and doing something similar did not yield further significant improvements. Adding a white filter a la the red, yellow, and green filters did not yield any further improvement and actually worsened the accuracy for some photos.
- Look Angle (only problem for Look Light)
- I experimented with various parameter ranges / thresholds in the Hough transforms to be more “lenient” in detecting curved edges that don’t strictly form perfect circles. In combination with red, yellow, green filters, there was some success, but the parameters need to be further fine tuned.
- Possible Amended Combined Approach
- With regularization on the actual size of the traffic light (assuming that Yasaswini’s algorithm passes in the image of just the light in the scene to this algorithm), I am hypothesizing that simply applying each color filter and taking the sum of the resultant pixel values will yield the light color for the Look Light with the highest probability. I will test this out next week.
Progress
Not as much progress as desired. Improvements w.r.t. exposure and look angle were not as high as desired. Hopefully, the amended combined approach is a useful experiment. If accurate, it certainly will cut down on latency too, a metric I haven’t been paying too much attention to as of yet.
Deliverables for Next Week
- Experimentation with amended combined approach, above.
- Further improvements w.r.t exposure and look angle.