university computervision week1 theory

Image Representation in NumPy and OpenCV

Source:

Indexing

The lecture uses:

  • F[y, x]
  • equivalently F[i, j]

So the first index is the row and the second is the column.

Color images

  • shape is typically H x W x 3
  • OpenCV stores channels as BGR
  • a fourth channel can store transparency

This matters because it is easy to accidentally assume RGB or swap x and y.