Why vision is not both hierarchical and feedforward
Identifieur interne : 003429 ( Ncbi/Checkpoint ); précédent : 003428; suivant : 003430Why vision is not both hierarchical and feedforward
Auteurs : Michael H. Herzog ; Aaron M. ClarkeSource :
- Frontiers in Computational Neuroscience [ 1662-5188 ] ; 2014.
Abstract
In classical models of object recognition, first, basic features (e.g., edges and lines) are analyzed by independent filters that mimic the receptive field profiles of V1 neurons. In a feedforward fashion, the outputs of these filters are fed to filters at the next processing stage, pooling information across several filters from the previous level, and so forth at subsequent processing stages. Low-level processing determines high-level processing. Information lost on lower stages is irretrievably lost. Models of this type have proven to be very successful in many fields of vision, but have failed to explain object recognition in general. Here, we present experiments that, first, show that, similar to demonstrations from the Gestaltists, figural aspects determine low-level processing (as much as the other way around). Second, performance on a single element depends on all the other elements in the visual scene. Small changes in the overall configuration can lead to large changes in performance. Third, grouping of elements is key. Only if we know how elements group across the entire visual field, can we determine performance on individual elements, i.e., challenging the classical stereotypical filtering approach, which is at the very heart of most vision models.
Url:
DOI: 10.3389/fncom.2014.00135
PubMed: 25374535
PubMed Central: 4205941
Affiliations:
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<record><TEI><teiHeader><fileDesc><titleStmt><title xml:lang="en">Why vision is not both hierarchical <italic>and</italic> feedforward</title><author><name sortKey="Herzog, Michael H" sort="Herzog, Michael H" uniqKey="Herzog M" first="Michael H." last="Herzog">Michael H. Herzog</name></author><author><name sortKey="Clarke, Aaron M" sort="Clarke, Aaron M" uniqKey="Clarke A" first="Aaron M." last="Clarke">Aaron M. Clarke</name></author></titleStmt><publicationStmt><idno type="wicri:source">PMC</idno><idno type="pmid">25374535</idno><idno type="pmc">4205941</idno><idno type="url">http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4205941</idno><idno type="RBID">PMC:4205941</idno><idno type="doi">10.3389/fncom.2014.00135</idno><date when="2014">2014</date><idno type="wicri:Area/Pmc/Corpus">002664</idno><idno type="wicri:Area/Pmc/Curation">002664</idno><idno type="wicri:Area/Pmc/Checkpoint">000806</idno><idno type="wicri:Area/Ncbi/Merge">003429</idno><idno type="wicri:Area/Ncbi/Curation">003429</idno><idno type="wicri:Area/Ncbi/Checkpoint">003429</idno></publicationStmt><sourceDesc><biblStruct><analytic><title xml:lang="en" level="a" type="main">Why vision is not both hierarchical <italic>and</italic> feedforward</title><author><name sortKey="Herzog, Michael H" sort="Herzog, Michael H" uniqKey="Herzog M" first="Michael H." last="Herzog">Michael H. Herzog</name></author><author><name sortKey="Clarke, Aaron M" sort="Clarke, Aaron M" uniqKey="Clarke A" first="Aaron M." last="Clarke">Aaron M. Clarke</name></author></analytic><series><title level="j">Frontiers in Computational Neuroscience</title><idno type="eISSN">1662-5188</idno><imprint><date when="2014">2014</date></imprint></series></biblStruct></sourceDesc></fileDesc><profileDesc><textClass></textClass></profileDesc></teiHeader><front><div type="abstract" xml:lang="en"><p>In classical models of object recognition, first, basic features (e.g., edges and lines) are analyzed by independent filters that mimic the receptive field profiles of V1 neurons. In a feedforward fashion, the outputs of these filters are fed to filters at the next processing stage, pooling information across several filters from the previous level, and so forth at subsequent processing stages. Low-level processing determines high-level processing. Information lost on lower stages is irretrievably lost. Models of this type have proven to be very successful in many fields of vision, but have failed to explain object recognition in general. Here, we present experiments that, first, show that, similar to demonstrations from the Gestaltists, figural aspects determine low-level processing (as much as the other way around). Second, performance on a single element depends on all the other elements in the visual scene. Small changes in the overall configuration can lead to large changes in performance. Third, grouping of elements is key. Only if we know how elements group across the entire visual field, can we determine performance on individual elements, i.e., challenging the classical stereotypical filtering approach, which is at the very heart of most vision models.</p></div></front><back><div1 type="bibliography"><listBibl><biblStruct><analytic><author><name sortKey="Amit, Y" uniqKey="Amit Y">Y. Amit</name></author><author><name sortKey="Trouve, A" uniqKey="Trouve A">A. 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Grossberg</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Estrada, F J" uniqKey="Estrada F">F. J. Estrada</name></author><author><name sortKey="Elder, J H" uniqKey="Elder J">J. H. Elder</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Fei Fei, L" uniqKey="Fei Fei L">L. Fei-Fei</name></author><author><name sortKey="Fergus, R" uniqKey="Fergus R">R. Fergus</name></author><author><name sortKey="Perona, P" uniqKey="Perona P">P. Perona</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Felzenszwalb, P F" uniqKey="Felzenszwalb P">P. F. Felzenszwalb</name></author><author><name sortKey="Huttenlocher, D P" uniqKey="Huttenlocher D">D. P. Huttenlocher</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Fergus, R" uniqKey="Fergus R">R. Fergus</name></author><author><name sortKey="Perona, P" uniqKey="Perona P">P. Perona</name></author><author><name sortKey="Zisserman, A" uniqKey="Zisserman A">A. Zisserman</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Fink, M" uniqKey="Fink M">M. Fink</name></author><author><name sortKey="Perona, P" uniqKey="Perona P">P. Perona</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Francis, G" uniqKey="Francis G">G. Francis</name></author><author><name sortKey="Grossberg, S" uniqKey="Grossberg S">S. Grossberg</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Francis, G" uniqKey="Francis G">G. Francis</name></author><author><name sortKey="Grossberg, S" uniqKey="Grossberg S">S. Grossberg</name></author><author><name sortKey="Mingolla, E" uniqKey="Mingolla E">E. Mingolla</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Gershon, E D" uniqKey="Gershon E">E. D. Gershon</name></author><author><name sortKey="Wiener, M C" uniqKey="Wiener M">M. C. Wiener</name></author><author><name sortKey="Latham, P E" uniqKey="Latham P">P. E. Latham</name></author><author><name sortKey="Richmond, B J" uniqKey="Richmond B">B. J. Richmond</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Goodfellow, I J" uniqKey="Goodfellow I">I. J. Goodfellow</name></author><author><name sortKey="Courville, A" uniqKey="Courville A">A. Courville</name></author><author><name sortKey="Bengio, Y" uniqKey="Bengio Y">Y. Bengio</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Grossberg, S" uniqKey="Grossberg S">S. Grossberg</name></author><author><name sortKey="Mignolla, E" uniqKey="Mignolla E">E. Mignolla</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Heisele, B" uniqKey="Heisele B">B. Heisele</name></author><author><name sortKey="Serre, T" uniqKey="Serre T">T. Serre</name></author><author><name sortKey="Poggio, T" uniqKey="Poggio T">T. Poggio</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Hermens, F" uniqKey="Hermens F">F. Hermens</name></author><author><name sortKey="Herzog, M H" uniqKey="Herzog M">M. H. Herzog</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Herzog, M H" uniqKey="Herzog M">M. H. Herzog</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Hoiem, D" uniqKey="Hoiem D">D. Hoiem</name></author><author><name sortKey="Efros, A A" uniqKey="Efros A">A. A. Efros</name></author><author><name sortKey="Hebert, M" uniqKey="Hebert M">M. Hebert</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Hung, C P" uniqKey="Hung C">C. P. Hung</name></author><author><name sortKey="Kreiman, G" uniqKey="Kreiman G">G. Kreiman</name></author><author><name sortKey="Poggio, T" uniqKey="Poggio T">T. Poggio</name></author><author><name sortKey="Dicarlo, J J" uniqKey="Dicarlo J">J. J. DiCarlo</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Kruger, N" uniqKey="Kruger N">N. Krüger</name></author><author><name sortKey="Janssen, P" uniqKey="Janssen P">P. Janssen</name></author><author><name sortKey="Kalkan, S" uniqKey="Kalkan S">S. Kalkan</name></author><author><name sortKey="Lappe, M" uniqKey="Lappe M">M. Lappe</name></author><author><name sortKey="Leonardis, A" uniqKey="Leonardis A">A. Leonardis</name></author><author><name sortKey="Piater, J" uniqKey="Piater J">J. Piater</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Livne, T" uniqKey="Livne T">T. Livne</name></author><author><name sortKey="Sagi, D" uniqKey="Sagi D">D. Sagi</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Malania, M" uniqKey="Malania M">M. Malania</name></author><author><name sortKey="Herzog, M H" uniqKey="Herzog M">M. H. Herzog</name></author><author><name sortKey="Westheimer, G" uniqKey="Westheimer G">G. Westheimer</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Malik, J" uniqKey="Malik J">J. Malik</name></author><author><name sortKey="Belongie, S" uniqKey="Belongie S">S. Belongie</name></author><author><name sortKey="Leung, T" uniqKey="Leung T">T. Leung</name></author><author><name sortKey="Shi, J" uniqKey="Shi J">J. Shi</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Malik, J" uniqKey="Malik J">J. Malik</name></author><author><name sortKey="Belongie, S" uniqKey="Belongie S">S. Belongie</name></author><author><name sortKey="Shi, J" uniqKey="Shi J">J. Shi</name></author><author><name sortKey="Leung, T" uniqKey="Leung T">T. Leung</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Manassi, M" uniqKey="Manassi M">M. Manassi</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Manassi, M" uniqKey="Manassi M">M. Manassi</name></author><author><name sortKey="Herzog, M" uniqKey="Herzog M">M. Herzog</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Manassi, M" uniqKey="Manassi M">M. Manassi</name></author><author><name sortKey="Sayim, B" uniqKey="Sayim B">B. Sayim</name></author><author><name sortKey="Herzog, M H" uniqKey="Herzog M">M. H. Herzog</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Manassi, M" uniqKey="Manassi M">M. Manassi</name></author><author><name sortKey="Sayim, B" uniqKey="Sayim B">B. Sayim</name></author><author><name sortKey="Herzog, M H" uniqKey="Herzog M">M. H. Herzog</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Martin, D R" uniqKey="Martin D">D. R. Martin</name></author><author><name sortKey="Fowlkes, C C" uniqKey="Fowlkes C">C. C. Fowlkes</name></author><author><name sortKey="Malik, J" uniqKey="Malik J">J. Malik</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Oberfeld, D" uniqKey="Oberfeld D">D. Oberfeld</name></author><author><name sortKey="Stahn, P" uniqKey="Stahn P">P. Stahn</name></author><author><name sortKey="Kuta, M" uniqKey="Kuta M">M. Kuta</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Overvliet, K" uniqKey="Overvliet K">K. Overvliet</name></author><author><name sortKey="Sayim, B" uniqKey="Sayim B">B. Sayim</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Pelli, D G" uniqKey="Pelli D">D. G. Pelli</name></author><author><name sortKey="Palomares, M" uniqKey="Palomares M">M. Palomares</name></author><author><name sortKey="Majaj, N J" uniqKey="Majaj N">N. J. Majaj</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Ren, X" uniqKey="Ren X">X. Ren</name></author><author><name sortKey="Malik, J" uniqKey="Malik J">J. Malik</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Riesenhuber, M" uniqKey="Riesenhuber M">M. Riesenhuber</name></author><author><name sortKey="Poggio, T" uniqKey="Poggio T">T. Poggio</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Rodriguez Sanchez, A J" uniqKey="Rodriguez Sanchez A">A. J. Rodriguez-Sanchez</name></author><author><name sortKey="Simine, E" uniqKey="Simine E">E. Simine</name></author><author><name sortKey="Tsotsos, J K" uniqKey="Tsotsos J">J. K. Tsotsos</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Saarela, T P" uniqKey="Saarela T">T. P. Saarela</name></author><author><name sortKey="Herzog, M H" uniqKey="Herzog M">M. H. Herzog</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Saarela, T P" uniqKey="Saarela T">T. P. Saarela</name></author><author><name sortKey="Herzog, M H" uniqKey="Herzog M">M. H. Herzog</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Saarela, T P" uniqKey="Saarela T">T. P. Saarela</name></author><author><name sortKey="Westheimer, G" uniqKey="Westheimer G">G. Westheimer</name></author><author><name sortKey="Herzog, M H" uniqKey="Herzog M">M. H. Herzog</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Salakhutdinov, R" uniqKey="Salakhutdinov R">R. Salakhutdinov</name></author><author><name sortKey="Tenenbaum, J B" uniqKey="Tenenbaum J">J. B. Tenenbaum</name></author><author><name sortKey="Torralba, A" uniqKey="Torralba A">A. Torralba</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Sayim, B" uniqKey="Sayim B">B. Sayim</name></author><author><name sortKey="Westheimer, G" uniqKey="Westheimer G">G. Westheimer</name></author><author><name sortKey="Herzog, M H" uniqKey="Herzog M">M. H. Herzog</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Schneiderman, H" uniqKey="Schneiderman H">H. Schneiderman</name></author><author><name sortKey="Kanade, T" uniqKey="Kanade T">T. Kanade</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Serre, T" uniqKey="Serre T">T. Serre</name></author><author><name sortKey="Oliva, A" uniqKey="Oliva A">A. Oliva</name></author><author><name sortKey="Poggio, T" uniqKey="Poggio T">T. Poggio</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Serre, T" uniqKey="Serre T">T. Serre</name></author><author><name sortKey="Wolf, L" uniqKey="Wolf L">L. Wolf</name></author><author><name sortKey="Bileschi, S" uniqKey="Bileschi S">S. Bileschi</name></author><author><name sortKey="Riesenhuber, M" uniqKey="Riesenhuber M">M. Riesenhuber</name></author><author><name sortKey="Poggio, T" uniqKey="Poggio T">T. Poggio</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Serre, T" uniqKey="Serre T">T. Serre</name></author><author><name sortKey="Wolf, L" uniqKey="Wolf L">L. Wolf</name></author><author><name sortKey="Poggio, T" uniqKey="Poggio T">T. Poggio</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Shi, J" uniqKey="Shi J">J. Shi</name></author><author><name sortKey="Malik, J" uniqKey="Malik J">J. Malik</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Shpaner, M" uniqKey="Shpaner M">M. Shpaner</name></author><author><name sortKey="Molholm, S" uniqKey="Molholm S">S. Molholm</name></author><author><name sortKey="Forde, E" uniqKey="Forde E">E. Forde</name></author><author><name sortKey="Foxe, J J" uniqKey="Foxe J">J. J. Foxe</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Thorpe, S" uniqKey="Thorpe S">S. Thorpe</name></author><author><name sortKey="Delorme, A" uniqKey="Delorme A">A. Delorme</name></author><author><name sortKey="Van Rullen, R" uniqKey="Van Rullen R">R. Van Rullen</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Torralba, A" uniqKey="Torralba A">A. Torralba</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Tsotsos, J K" uniqKey="Tsotsos J">J. K. Tsotsos</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Tsotsos, J K" uniqKey="Tsotsos J">J. K. Tsotsos</name></author><author><name sortKey="Culhane, S M" uniqKey="Culhane S">S. M. Culhane</name></author><author><name sortKey="Kei Wai, W Y" uniqKey="Kei Wai W">W. Y. Kei Wai</name></author><author><name sortKey="Lai, Y" uniqKey="Lai Y">Y. 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