Applying Deep Neural Network Techniques for LArTPC Data - - PowerPoint PPT Presentation

applying deep neural network techniques for lartpc data
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Applying Deep Neural Network Techniques for LArTPC Data - - PowerPoint PPT Presentation

Applying Deep Neural Network Techniques for LArTPC Data Reconstruction Laura Domine (Stanford University / SLAC) Fermilab Machine Learning Group meeting - 11/7/18 Plan 1. LArTPC & Deep Learning 2. Examples of applications: UResNet &


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Applying Deep Neural Network Techniques for LArTPC Data Reconstruction

Laura Domine (Stanford University / SLAC) Fermilab Machine Learning Group meeting - 11/7/18

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Plan

1. LArTPC & Deep Learning 2. Examples of applications: UResNet & PPN networks 3. Sparse convolutions

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LArTPC & Deep Learning

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Liquid Argon Time Projection Chamber (LArTPC)

Neutrino detectors Ex: MicroBooNE @ Fermilab, 150 tons 2D or 3D data Bigger and bigger! (DUNE)

Neutrinos.

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Deep Neural Networks (DNN) & Computer Vision

Picture from Martin Görner

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Deep Neural Networks (DNN) & Computer Vision

Semantic segmentation Object detection & classification

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Towards a full reconstruction chain with DNN

  • Currently: Lots of heuristic algorithms
  • Goal: Replace them with a set of DNN

algorithms which ideally will

○ Run faster ○ Have a better performance

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Towards a full reconstruction chain with DNN

Steps: 1. Point detection (track edge)

Non-contractual picture - Actual product may differ

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Towards a full reconstruction chain with DNN

Steps: 1. Point detection (track edge) PPN

Non-contractual picture - Actual product may differ

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Towards a full reconstruction chain with DNN

Steps: 1. Point detection (track edge) PPN 2. Pixel-wise labeling (particle track vs electromagnetic shower)

Non-contractual picture - Actual product may differ

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Towards a full reconstruction chain with DNN

Steps: 1. Point detection (track edge) PPN 2. Pixel-wise labeling (particle track vs electromagnetic shower) UResNet

Non-contractual picture - Actual product may differ

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Towards a full reconstruction chain with DNN

Steps: 1. Point detection (track edge) PPN 2. Pixel-wise labeling (particle track vs electromagnetic shower) UResNet 3. Clustering of energy deposits and instance segmentation

Non-contractual picture - Actual product may differ

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Towards a full reconstruction chain with DNN

Steps: 1. Point detection (track edge) PPN 2. Pixel-wise labeling (particle track vs electromagnetic shower) UResNet 3. Clustering of energy deposits and instance segmentation Work in progress!

Non-contractual picture - Actual product may differ

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Towards a full reconstruction chain with DNN

Steps: 1. Point detection (track edge) PPN 2. Pixel-wise labeling (particle track vs electromagnetic shower) UResNet 3. Clustering of energy deposits and instance segmentation Work in progress! 4. Particle identification and energy estimate 5. Hierarchical reconstruction

Non-contractual picture - Actual product may differ

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Examples of applications: UResNet and PPN networks

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Semantic Segmentation: UResNet

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Semantic Segmentation: UResNet

Residual connections

Encoder Decoder

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Semantic Segmentation: UResNet

A Deep Neural Network for Pixel-Level Electromagnetic Particle Identification in the MicroBooNE Liquid Argon Time Projection Chamber. https://arxiv.org/abs/1808.07269

Data Physicist’s label Network’s output

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Point-finding: PPN

Inspired by Faster-RCNN architecture

  • Region Proposal Network detects

regions of interest

  • Replace regions with points =

Pixel Proposal Network (PPN) Why not Mask-RCNN?

○ Computations expensive ○ Our features topology is different (track, shower)

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PPN proposals

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PPN needs post-processing

+ scores…!

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PPN needs post-processing

Option 1: DBSCAN

  • Density estimation algorithm
  • No prior on the number of clusters.

Option 2: NMS (Non-Maximal Suppression)

  • Popular post-processing method for object

detection

  • Order by score and prune boxes with too much
  • verlap
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NB: independently of DBSCAN vs NMS, these plots also benefit from debugged ground truth pixels position. ZOOM

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Together

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24cm 2 4 c m 6mm/voxel

3D Analysis

UResNet + PPN

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24cm 24cm 6mm/voxel

3D Analysis

UResNet + PPN

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Sparse UResNet

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How do we handle sparse data?

Dense Sparse

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Naive approach

Input: dense 3D matrix of energy deposits.

  • Crop your data
  • Run the network on small cropped images
  • Stitch together results

Many cropping algorithms possible Compromises to make:

  • Maximize the number of overlapping boxes (accuracy)
  • Minimize the number of boxes (computation time)
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Sparse Convolutions

Many possible definitions and implementations of ‘sparse convolutions’... Submanifold Sparse Convolutions: https://github.com/facebookresearch/SparseConvNet Submanifold? “input data with lower effective dimension than the space in which it lives” Ex: 1D curve in 2+D space, 2D surface in 3+D space Our case: the worst! 1D curve in 3D space...

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Sparse Convolutions

Submanifold Sparse Convolutions: https://github.com/facebookresearch/SparseConvNet

3D Semantic Segmentation with Submanifold Sparse Convolutional Networks

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Sparse UResNet

Input: list of points coordinates and their features (e.g. energy deposition) With UResNet architecture:

  • >99.9% accuracy in 3D
  • Faster training (less computations!): only a few hours
  • Much lower memory usage

Example in larcv-viewer

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Summary

  • Extract interesting / useful features with deep neural networks:

○ Points of interest with PPN ○ Pixel-wise classification track vs shower with UResNet

  • Currently working on clustering and instance segmentation

(particle type, particle instances)

  • Sparse techniques are very exciting!

Join DeepLearnPhysics group!

  • Technical discussion on ML applied to experimental physics data
  • Data + code sharing for reproducibility
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Thank you!

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Backup slides

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PPN Loss: details