tfm.vision.anchor.Anchor

Anchor class for anchor-based object detectors.

tfm.vision.anchor.Anchor(
    min_level, max_level, num_scales, aspect_ratios, anchor_size, image_size
)

Example:

anchor_boxes = Anchor(
    min_level=3,
    max_level=4,
    num_scales=2,
    aspect_ratios=[0.5, 1., 2.],
    anchor_size=4.,
    image_size=[256, 256],
).multilevel_boxes

min_level integer number of minimum level of the output feature pyramid.
max_level integer number of maximum level of the output feature pyramid.
num_scales integer number representing intermediate scales added on each level. For instances, num_scales=2 adds one additional intermediate anchor scales [2^0, 2^0.5] on each level.
aspect_ratios list of float numbers representing the aspect ratio anchors added on each level. The number indicates the ratio of width to height. For instances, aspect_ratios=[1.0, 2.0, 0.5] adds three anchors on each scale level.
anchor_size float number representing the scale of size of the base anchor to the feature stride 2^level.
image_size a list of integer numbers or Tensors representing [height, width] of the input image size.
multilevel_boxes an OrderedDict from level to the generated anchor boxes of shape [height_l, width_l, num_anchors_per_location * 4].
anchors_per_location number of anchors per pixel location.