Computer Vision Foundations · free preview

Blending and Steerable Pyramids

Blending per Laplacian band under a Gaussian-pyramid mask removes seams by widening transitions with level, and the steerable pyramid adds orientation subbands to reach a multiscale oriented self-inverting non-aliased representation.

1. The seam problem

The seam problem

2. Blend in every band

Blend in every band

3. Adding orientation

Adding orientation

4. Four transforms, one picture

Four transforms, one picture

5. Where the seam survives

Why does a single soft mask blended on the original image leave a visible seam between two textures, while blending inside the Laplacian pyramid removes it?

6. Choosing a transform family

A compression system must rebuild the image from as few numbers as the transform allows, with no redundancy. Which family fits, and what does it give up?

7. Mask levels for seven bands

Blending an image with 7 Laplacian band levels needs a Gaussian mask pyramid. Write the total number of mask levels including the residual.

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