Skip to content

Commit

Permalink
docs: fixed information in the README about the parameters used
Browse files Browse the repository at this point in the history
  • Loading branch information
ksakmann committed Feb 25, 2017
1 parent a4e505e commit 7626b15
Showing 1 changed file with 2 additions and 3 deletions.
5 changes: 2 additions & 3 deletions README.md
Original file line number Diff line number Diff line change
Expand Up @@ -63,7 +63,7 @@ I experimented with a number of different combinations of color spaces and HOG p
## Training a linear SVM on the final choice of features

I trained a linear SVM using all channels of images converted to HLS space. I included spatial features color features as well as all three HLS channels, because using less than all three channels reduced the accuracy considerably.
The final feature vector has a length of 1836, most of which are HOG features. For color binning patches of `spatial_size=(16,16)` were generated and color histograms
The final feature vector has a length of 6156 elements, most of which are HOG features. For color binning patches of `spatial_size=(16,16)` were generated and color histograms
were implemented using `hist_bins=32` used. After training on the training set this resulted in a validation and test accuracy of 98%. The average time for a prediction (average over a hundred predictions) turned out to be about 3.3ms on an i7 processor, thus allowing a theoretical bandwidth of 300Hz. A realtime application would therfore only feasible if several parts of the image are examined in parallel in a similar time.
The sliding window search described below is an embarrassingly parallel task and corresponding speedups can be expected, but implementing it is beyond the scope of this project.
Using just the L channel reduced the feature vector to about a third, while test and validation accuracy dropped to about 94.5% each. Unfortunately, the average time for a prediction remained about the same as before. The classifier used was `LinearSVC` taken from the `scikit-learn` package.
Expand All @@ -83,8 +83,7 @@ The window sizes are 240,180,120 and 70 pixels for each zone. Within each zone

## Search examples
The final classifier uses four scales and HOG features from all 3 channels of images in HLS space. The feature vector contains also spatially binned color and histograms of color features
False positives occured much more frequently for `pixels_per_cell=8` compared to `pixels_per_cell=16`. Using this larger value also had the pleasant side effect of a smaller
feature vector and sped up the evaluation. The remaining false positives
False positives occured more frequently for `pixels_per_cell=8` compared to `pixels_per_cell=16`, but nevertheless produced better results when applied to the video. The false positives
were filtered out by using a heatmap approach as described below. Here are some typical examples of detections

![DetectionExamples][image5]
Expand Down

0 comments on commit 7626b15

Please sign in to comment.