Paper-Survey: Objects as Points

Transcript

1. ࿦จLT: Objects as Points
   h"ps:/
   /arxiv.org/abs/1904.07850
   2019/04/19 ౻ຊ༟հ
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2. ໨࣍
   • ஶऀ৘ใ
   • ֓ཁ
   • ͜Ε·ͰͷϞσϧͱͷҧ͍
   • ਫ਼౓
   • ͦͷଞײ૝
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3. ஶऀ৘ใ
   • Xingyi Zhou(UT Aus1n)
   • Dequan Wang(UC Berkeley)
   • Philipp Krähenbühl(UT Aus1n)
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4. ಛ௃
   • ෺ମݕग़Ϟσϧ
   • ༗໊ͳྫ: SSD, YOLOv3, Re.naNet, M2Det...
   • ݕग़ͷΈͳΒͣ࢟੎ɾdepthɾ޲͖ɾ3d size ౳ʹ΋ద༻͍ͯ͠Δ
   • backbone ͱͯ͠ DLA(deep layers aggrega.on) ΍ Hourglass(CornerNet ౳Ͱ࢖
   ༻) Λ࢖༻
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5. ಛ௃
   • bounding box Λ࢖Θͣʹݕग़Λߦ͏Ϟσϧ(keypointਪఆ)
   • bounding box ༻ͷ grid ͷ୅ΘΓʹ໨͕ࡉ͔͍ heatmap(H, W Λ4Ͱׂͬͨఔ
   ౓ͷ΋ͷ) Λग़ྗ
   • heatmap ͕ߴ͍৔ॴ(௖఺) Λ෺ମͷத৺ͱਪఆ
   • த৺ͱͳΔ৔ॴͷ feature ͔Β෺ମͷେ͖͞ɾ཭ࢄԽޡࠩΛਪఆ
   • ཭ࢄԽޡࠩ = heatmap ʹͨ͠ࡍͷޡࠩ
   • େ͖͞ʹ͍ͭͯ͸ scale ͍ͯ͠ͳ͍(ͦͷ··ͷ஋)
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6. ಛ௃
   • ༧ଌϘοΫε = heatmap ͷ࠲ඪ + ༧ଌϘοΫεαΠζ + ༧ଌ཭ࢄԽޡࠩ
   • ֶशʹ࢖͏ heatmap ͷ఺͸ 1෺ମʹ͖ͭ 1ͭͷΈ
   • SSD ౳ͷΑ͏ʹ IoU ͷॏͳΓ۩߹Ͱ background ͔൱͔Λ෼͚ͳ͍
   • ෳ਺ box ग़͞ͳ͍͜ͱΛલఏͱ͍ͯ͠Δ
   • ಉ͡ΫϥεͰॏͳͬͯ͠·͏৔߹͕͋Δ͕શମͷ 0.1 % ະຬͰ RCNN(2% ະ
   ຬ) ΑΓখ͍͞
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7. Πϝʔδਤ
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8. ͜Ε·ͰͷϞσϧͱͷҧ͍
   • Object detec*on with implicit anchors(SSD, YOLO, Re*naNet ౳)ͱͷҧ͍
   • CenterNet͸ശͷॏͳΓͰ͸ͳ͘ҐஔͷΈʹج͍ͮͯʮΞϯΧʔʯΛׂ౰
   • લܠͱഎܠͷ෼ྨʹؔ͢Δखಈͷ͖͍͠஋͸ͳ͍(IoU 0.5 > ͱ͔)
   • ෺ମຖʹϙδςΟϒͳΞϯΧʔ͸1͚ͭͩͳͷͰ NMS Λඞཁͱ͠ͳ͍
   • We simply extract local peaks in the keypoint heatmap
   • keypoint heatmap ͔ΒϩʔΧϧϐʔΫΛநग़͢Δ͚ͩͰྑ͍
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9. ͜Ε·ͰͷϞσϧͱͷҧ͍
   • Object detec*on with implicit anchors(SSD, YOLO, Re*naNet ౳)ͱͷҧ͍
   • CenterNet͸ΑΓେ͖ͳग़ྗղ૾౓Λ࢖͏
   • mask r-cnn ͱ͔ͱൺֱͯ͠
   • output stride of 16
   • ͜ΕʹΑΓෳ਺ͷΞϯΧʔ͕ෆཁͱͳΔʁʁʁʁ
   • [1711.08189] An Analysis of Scale Invariance in Object Detec*on - SNIP
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10. ͜Ε·ͰͷϞσϧͱͷҧ͍
    • Object detec*on by keypoint es*ma*on(CornerNet, ExtremeNet ౳)ͱͷҧ͍
    • ্ه 2ͭ͸ keypoint ݕग़ޙʹ ૊Έ߹ΘͤΛ grouping ͢Δඞཁ͕͋Δ
    • ஗͘ͳͬͯ͠·͏
    • CenterNet ͸ඞཁͱ͠ͳ͍
    • ଎͍ʂ
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11. ਫ਼౓
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12. ਫ਼౓(M2Det ͷ݁ՌΛ໨ࢹͰ௥Ճͯ͠Έͨ)
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13. ͦͷଞײ૝
    • Backbone ͱͯ͠ DLA Λ࢖͑ΔͷΛॳΊͯ஌ͬͨ
    • Ή͠Ζ DLA ॳΊͯ஌Γ·ͨ͠
    !
    • NMS ͕ෆཁʹͳΔͷ͸஍ຯʹخ͍͠
    • anchor ͕ফ͑Δͷ΋خ͍͠
    • খ͍͞෺ମʹରͯ͠ͲΕ͚ͩରԠͰ͖Δ͔֬ೝ͠ͳ͍ͱ
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