(height, width, feat_stride, anchor_scales=(8, 16, 32),
                         anchor_ratios=(0.5, 1, 2), base_size=16)
return anchors
A wrapper function to generate anchors given different scales
      Also return the number of anchors in variable 'length'
A wrapper function to generate anchors given different scales
      Also return the number of anchors in variable 'length'
A wrapper function to generate anchors given different scales Also return the number of anchors in variable length
def generate_anchors_pre(height, width, feat_stride, anchor_scales=(8, 16, 32),
                         anchor_ratios=(0.5, 1, 2), base_size=16):
    """ A wrapper function to generate anchors given different scales
      Also return the number of anchors in variable 'length'
    """
    anchors = generate_anchors(
        base_size=base_size, ratios=np.array(anchor_ratios),
        scales=np.array(anchor_scales))
    A = anchors.shape[0]
    shift_x = np.arange(0, width) * feat_stride
    shift_y = np.arange(0, height) * feat_stride
    shift_x, shift_y = np.meshgrid(shift_x, shift_y)
    shifts = np.vstack((shift_x.ravel(), shift_y.ravel(), shift_x.ravel(),
                        shift_y.ravel())).transpose()
    K = shifts.shape[0]
    # width changes faster, so here it is H, W, C
    anchors = anchors.reshape((1, A, 4)) + shifts.reshape((1, K, 4)).transpose(
        (1, 0, 2))
    anchors = anchors.reshape((K * A, 4)).astype(np.float32, copy=False)

    return anchors
def generate_anchors_pre ( height , width , feat_stride , anchor_scales = ( 8 , 16 , 32 ) , anchor_ratios = ( 0.5 , 1 , 2 ) , base_size = 16 ) : anchors = generate_anchors ( base_size = base_size , ratios = np . array ( anchor_ratios ) , scales = np . array ( anchor_scales ) ) A = anchors . shape [ 0 ] shift_x = np . arange ( 0 , width ) * feat_stride shift_y = np . arange ( 0 , height ) * feat_stride shift_x , shift_y = np . meshgrid ( shift_x , shift_y ) shifts = np . vstack ( ( shift_x . ravel ( ) , shift_y . ravel ( ) , shift_x . ravel ( ) , shift_y . ravel ( ) ) ) . transpose ( ) K = shifts . shape [ 0 ] # width changes faster, so here it is H, W, C anchors = anchors . reshape ( ( 1 , A , 4 ) ) + shifts . reshape ( ( 1 , K , 4 ) ) . transpose ( ( 1 , 0 , 2 ) ) anchors = anchors . reshape ( ( K * A , 4 ) ) . astype ( np . float32 , copy = False ) return anchors