CS-F441: S ELECTED TOPICS FROM COMPUTER S CIENCE (DEEP L EARNING FOR NLP & CV) Lecture-KT-10: SIFT, HOG Dr. Kamlesh Tiwari, Assistant Professor, Department of Computer Science and Information Systems, BITS Pilani, Rajasthan-333031 INDIA Nov 06, 2019 (Campus @ BITS-Pilani July-Dec 2019)
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CS-F441: Selected Topics from Computer Science (Deep Learning for NLP & CV) · 2019-11-06 · CS-F441: SELECTED TOPICS FROM COMPUTER SCIENCE (DEEP LEARNING FOR NLP & CV) Lecture-KT-10:
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CS-F441: SELECTED TOPICS FROM COMPUTER
SCIENCE (DEEP LEARNING FOR NLP & CV)
Lecture-KT-10: SIFT, HOG
Dr. Kamlesh Tiwari,Assistant Professor,
Department of Computer Science and Information Systems,BITS Pilani, Rajasthan-333031 INDIA
Nov 06, 2019 (Campus @ BITS-Pilani July-Dec 2019)
Recap: Harris OperatorUse
f =λ1λ2
λ1 + λ2=
determinant(H)
trace(H)
Do the following:1 Compute cornerness score of each point2 Find points whose surrounding window gave large corner response
(f > threshold)3 Take the points of local maxima, i.e., perform non-maximum
Spatial selection: the magnitude of the Laplacian response will achievea maximum at the center of the blob, provided the scale of theLaplacian is “matched” to the scale of the blob
Take 64× 128 image, divide it into 16× 16 blocks of 50% overlapTotal blocks 7× 15 = 105. Block is 2× 2 cell of 8× 8 sizeQuantize orientation in 9 direction (amplitude is vote)Feature size 105× (2× 2)× 9 = 3780