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This overview details a computer demonstration on Non-negative Matrix Factorization (NMF) applied to three distinct datasets: face images, block shapes, and car images. The demonstration utilizes training sets comprising 2,429 face examples, block images of squares, rectangles, and circles, and 200 car images from various orientations. Key aspects discussed include the rank of basis images, number of iterations for convergence, and random noise effects. An exploration of the objective and update equations in NMF is also provided, highlighting practical choices and issues encountered during the process.
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NMF Demo: Lee, Seung Bryan Russell 6.899 Computer Demonstration
Overview • Training sets • Faces • Random noise • “Block world” • Cars • Issues/Choices • Rank • Number of iterations • Dataset
NMF: Equations • Objective Function:
NMF: Equations • Update equations:
Faces • Training set: 2429 examples • First 25 examples shown at right • Set consists of 19x19 centered face images
Faces • Basis Images: • Rank: 49 • Iterations: 50
Faces Original = x
Faces • Basis Images • Rank: 49 • Iterations: 500
Faces Original = x
Random • Training set: 2429 examples • First 25 examples listed to the right • Gray-level values generated randomly
Random • Basis Images • Rank: 49 • Iterations: 50
Random Original = x
Random • Basis Images • Rank: 49 • Iterations: 500
Random Original Output
Random Originals (1-25) Output (1-25)
“Blocks” • Training set: 2429 examples • First 25 examples listed to the right • Three “shapes”: squares, rectangles, and circles • Shapes centered at two points in image
“Blocks” • Basis Images • Rank: 25 • Iterations: 408
“Blocks” Original = x
“Blocks” Originals (1-25) Output (1-25)
“Blocks” Output (1-25)
“Blocks” • Basis Images • Rank: 49 • Iterations: 345
“Blocks” Originals (1-25) Output (1-25)
“Blocks” Output (1-25)
Cars • Training set: 200 examples • First 25 examples shown at right • Set consists of car images taken at various orientations
Cars • Basis Images • Rank: 49 • Iterations: 310 • Number of samples: 200
Cars Originals (1-25) Output (1-25)
Thanks! • CBCL for providing face and car images
For code and data, go to: www.ai.mit.edu/~brussell/courses/6.899/nmf