Fig. 4From: Classification of audio signals using spectrogram surfaces and extrinsic distortion measuresFlattening surfaces and measuring the resultant geometrical distortions, attained as shape descriptors. The process is visualized for the MIPS distortion energy, defined by (7). We first use ABCD algorithm [2], initialized with Tutte embedding, to map the triangulated surfaces into the plane. We then compute the Jacobian singular values \(\sigma _1(t)\) and \(\sigma _2(t)\) over each mesh triangle t. Finally, we compute for each distortion measure \(E(\sigma _1,\sigma _2)\) and mapping f the two quantities \(E_1(f)\) and \(E_2(f)\), defined according to (11) and (14)Back to article page