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Machine Learning for Design

Lecture 3

Machine Learning for Images. Part 1

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A bit more on regression and classification

And your very first contact with (deep) neural networks

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Linear Regression

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Finding the best parameter values

  • Training the model
  • Gradient Descent: an algorithm to find the minimum point of a function
  • Hyperparameters: parameters of the Gradient Descent
    • Learning Rate: speed of descent
    • Epochs: max number of steps
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Classification

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Fully connected Neural Network

  • Hyperparameters
    • Learning rate
    • Number of epochs
    • Architecture
      • #layers, #nodes, activation functions
    • Batch vs. mini-batch vs. stochastic gradient descent
    • Regularization parameters:
      • Dropout probability p
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Classifying into multiple classes - Softmax function

  • Return a probability for each class
    • example C1= ADMITTED, C2 = NOT ADMITTED, C3 = NEW TEST
    • p(C1) = 0.37, p(C2) = 0,21, p(C3) = 0,42
  • We use the Softmax activation function for the output layer
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Machine Learning and Images

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Images

  • Each pixel in an image is a feature
    • numerical
      • 0 or 1 for Black and White
      • Between 0 and 255 for greyscale
      • 16M values for RGB
  • Dimensionality -> n x m
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Computer Vision

Building algorithms that can “understand” the content of images and use it for other applications

  • It is a “Strong AI” problem
    • signal-to-symbol conversion
    • The semantic gap

A general-purpose vision system requires

  • Flexible, robust visual representation
  • Updated and maintained
  • Reasoning
  • Interfacing with attention goals, and plans
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What specific tasks can we train a CV system to perform?

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Stereolabs ZED Camera

3D Object Detection

Body tracking

Positional tracking

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Machine Learning for Design

Lecture 3

Machine Learning for Images. Part 1

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Credits

CMU Computer Vision course - Matthew O’Toole.

Grokking Machine Learning. Luis G. Serrano. Manning, 2021