Computer Vision Foundations · free preview

Downsampling and Upsampling

Downsampling as prefilter plus decimate with cascades for powers of two, and upsampling as zero-stuffing expansion plus an interpolation filter.

1. Downsampling is two operators in a trench coat

Downsampling is two operators in a trench coat

Expansion, the transpose

Interpolation filters fill the gaps

The two directions are not opposites

Which composition correctly defines downsampling an image by a factor of two, and why is the order of the operators not interchangeable?

The signal $[a, b]$ is expanded by $k = 2$ . Which statement about the result and its spectrum is correct?

The two-sample signal $[a, b]$ is expanded by a factor of $k = 2$ using zero-stuffing. Write the value at index 1 of the expanded signal.

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