WEEK-2
Weekly Update: 03-05-2021
Studied various ways and methods to obtain Video stream and their Pre-processing Techniques. Thus Concluded and developed Code for face detection. Details is as Follows.
This week we compared
different face detection models based on their performance.
The two models we majorly focused on are
1. Haar Cascade :
Object Detection using Haar feature-based cascade classifiers is an effective object detection method proposed by Paul Viola and Michael Jones in their paper, "Rapid Object Detection using a Boosted Cascade of Simple Features" in 2001. It is a machine learning based approach where a cascade function is trained from a lot of positive and negative images. It is then used to detect objects in other images.
2. Dlib’s Histogram of Oriented Gradients (HOG)
Comparison Examples:
Example 1:
Fig 1.A detection Haar model
Fig 1.B detection by dlib’s HOG model
· In the above images we can
observe that in fig 1.A Haar model produces many false positives like on the
pillar and pants.
· Whereas in fig 1.B dlib’s
model is more accurate and also do not produce any false detection results.
Example 2:
Fig 2.A detection Haar model
Fig 2.B detection dlib’s HOG model
· In the above images we can
observe that in both fig 2.A and 2.B models produces great results, even with
far faces.
Example 3:
Fig 3.A detection Haar model
Fig 3.B detection dlib’s HOG model
· In above fig 3.A we can see
that the model has detected the stomach as face, it clearly fails to classify
in this case.
· Whereas dlib’s model in fig
3.B has detected face correctly.
Code Snippets:
The examples we saw above were the Outputs obtained from the below Developed Code.
We have Timed the Execution to Analyze the models processing times.
1. Haar Cascade Model:
2.HOG Model:
Processing Speeds:
· A single frame takes about
0.85 secs in Dlib’s HOG model, whereas Haar classifier takes about 0.70 secs.
· Even though Haar classifier
are faster in processing , the results when compared the difference is very negligible.
Conclusion:
Clearly dlib’s Histogram of
Oriented Gradients produce way better results with a very minimal processing
time and computational power compared to haar cascade model.
Hence we use HOG models to
detect the face from the frame.
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