Anchor Grid Generation

Problem

Generate anchor boxes for every cell of a feature map.

For cell (i, j) the center is (j * stride + stride / 2, i * stride + stride / 2); emit one [cx, cy, w, h] entry per anchor in the order given, iterating cells row-major. Round center coordinates to 4 decimal places.

Test cases

case 1

in: [2,2,8,[[16,16],[32,32]]]

expected: [[4,4,16,16],[4,4,32,32],[12,4,16,16],[12,4,32,32],[4,12,16,16],[4,12,32,32],[12,12,16,16],[12,12,32,32]]

case 2

in: [1,1,16,[[10,20]]]

expected: [[8,8,10,20]]

case 3

in: [1,2,4,[[8,8]]]

expected: [[2,2,8,8],[6,2,8,8]]

Starter codePython

def anchor_grid(feature_h, feature_w, stride, anchors):
    # Your code here
    pass

3 test cases · run your code against them in the editor