2D and 3D image surface descriptors for fish otoliths classification authors: Ramon Reig i Bolaño (UVIC) Pere Martí i Puig (UVIC) Antoni Lombarte (ICM-CSIC) Vicenç Parisi i Baradad (UPC)

outline of the talk introduction: fish otoliths, AFORO database 2D contour descriptors new 2D contour descriptors 3D surfaces of otholits: proposal of extension 2nd. order descriptors (UDWT) conclusions

introduction: morphological description of fish otoliths drawing graphic representation taxonomy phylogeny paleontology paleoecology trophic relationships archeology digital photographs otolith measurements are used in: taxonomy (species identification) fisheries (stock identification, ageing) functional morphology and ecomorphology

introduction: AFORO database assembles image otoliths, morphometrics and shape analysis ICM collection 2456 high resolution images, 776 species and 156 families AFORO: shape analysis of fish otoliths Lombarte, A., Ò. Chic, V. Parisi-Baradad, R. Olivella, J. Piera & E. García-Ladona. 2006. A web-based environment from shape analysis of fish otoliths. The AFORO database. Scientia Marina 70: 147-152.

outline of the talk introduction: fish otoliths, AFORO database 2D contour descriptors new 2D contour descriptors 3D surfaces of otholits: proposal of extension 2nd. order descriptors (UDWT) conclusions

2D contour descriptors components xy high quality image binarized image contour lossy equiangular polar code lossless chain code 1st order CSS, curvature scale space wavelet analysis 2nd order

1st. order: equiangular radial values robust to affine transformation and origin lossy: non perfect reconstruction from polar to xy coordinates / contour

outline of the talk introduction: fish otoliths, AFORO database 2D contour descriptors new 2D contour descriptors 3D surfaces of otholits: proposal of extension 2nd. order descriptors (UDWT) conclusions

new 2D contour descriptors high quality image components xy binarized image contour reflected contour image 1st order lossless modified chain code lossy direct sampled y code

binary contour reflexion

non redundant contour

1st. order lossless coder: modified chain code 2 7 6 3 chain code : {1, 2, 1, 7, 6, 7, 1, 2, 2, 2, 1, 2, 1, 3, 3} how can avoid jumps 7,0,7,0... in a straight line -22,5º?

chain {a1a2a3....an} with aiє{0,1,2,3,4,5,6,7}, : modified chain code : chain {a1a2a3....an} with aiє{0,1,2,3,4,5,6,7}, : modified chain {b1b2b3....bn}, with b0=8 and bi integer minimizing |bi-bi-1| and (bi-ai)mod8 = 0 chain code :{1, 2, 1, 7, 6, 7, 1, 2, 2, 2, 1, 2, 1, 3, 3} {9,10,9,7,6,7,9,10,10,10,9,10,9,11,11} 10 11 9 12 8

1st. order lossy coder: direct sampled y

contour reconstruction (lossless vs. lossy)

outline of the talk introduction: fish otoliths, AFORO database 2D contour descriptors new 2D contour descriptors 3D surfaces of otholits: proposal of extension 2nd. order descriptors (UDWT) conclusions

3D surfaces of otholits volumetric 3D surface much more details for the classification/description process (i.e. the representation of the acoustic groove) normalized 3D data adquisition and orientation of otolith

proposal of extension to 3D surfaces high quality volume surface volume surface reflected on zy plane x z y lossy sampled surface, image on xy

proposal of extension to 3D surfaces high quality volume surface volume surface reflected on yx plane z y x lossy sampled surface, image on zx

outline of the talk introduction: fish otoliths, AFORO database 2D contour descriptors new 2D contour descriptors 3D surfaces of otholits: proposal of extension 2nd. order descriptors (UDWT) conclusions

2nd. order: UDWT (undecimated wavelet transf.) vd1 HPa1 va1 vd2 LPa1 HPa2 va2 vd3 LPa2 HPa3 va3 LPa3 ….

wavelet analysis of lossy sampled y code approximate (LP) details wav. (HP)

wavelet analysis of lossless modified chain code approximate (LP) details wav. (HP)

outline of the talk introduction: fish otoliths, AFORO database 2D contour descriptors new 2D contour descriptors 3D surfaces of otholits: proposal of extension 2nd. order descriptors (UDWT) conclusions & questions

conclusions we proposed a new lossy 2D contour coder (sampled y code) and a lossless one (modified chain code): based on reflection extensible to 3D surfaces (lossy sampled y code) can use 2nd. order descriptors drawback: need a normalized adquisition and positioning,

questions? thank you

DTW (dynamic time warping), alignment

DTW (dynamic time warping) algorithm accumulative differences matrix minimum distance path, backwards

filterbank

measure of MCC to find similar descriptors

introduction: AFORO database 2456 high resolution images, 776 species and 156 families morphometry shape analysis contours: FT (Fourier transform) CSS (curvature space scale) WT (wavelet analysis) authomatic taxonomy identification AFORO: shape analysis of fish otoliths Lombarte, A., Ò. Chic, V. Parisi-Baradad, R. Olivella, J. Piera & E. García-Ladona. 2006. A web-based environment from shape analysis of fish otoliths. The AFORO database. Scientia Marina 70: 147-152.

1st. order: shifted chain code robust to affine transformation and origin lossless: perfect reconstruction to xy coordinates / contour