Image Pyramid

Gaussian Pyramid

For each level

1. Blur image with an Gaussian filter
2. Down sample image

Convolution as matrix multiplication

Laplacian Pyramid

$G_0$ Downsampled Gaussian Pyramid Level 0 $F_0$ Upsampled Gaussian Pyramid Level 0

Laplacian Filter = $(I_0-F_0{G}_0)$

Compute the difference between upsampled Gaussian pyramid level k+1 and Gaussian pyramid level k.