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Add fit_output (False/True) option to PerspectiveTransform augmenter #452

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merged 2 commits into from
Oct 13, 2019
Merged

Add fit_output (False/True) option to PerspectiveTransform augmenter #452

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3081dca
Add fit_output (False/True) option to PerspectiveTransform augmenter
ZhengRui Oct 9, 2019
2829657
Calculate expanded WH properly
ZhengRui Oct 10, 2019
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22 changes: 21 additions & 1 deletion imgaug/augmenters/geometric.py
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Original file line number Diff line number Diff line change
Expand Up @@ -2547,7 +2547,7 @@ class PerspectiveTransform(meta.Augmenter):
"""

def __init__(self, scale=0, cval=0, mode='constant', keep_size=True,
polygon_recoverer="auto",
polygon_recoverer="auto", fit_output=False,
name=None, deterministic=False, random_state=None):
super(PerspectiveTransform, self).__init__(
name=name, deterministic=deterministic, random_state=random_state)
Expand All @@ -2573,6 +2573,8 @@ def __init__(self, scale=0, cval=0, mode='constant', keep_size=True,
if polygon_recoverer == "auto":
self.polygon_recoverer = _ConcavePolygonRecoverer()

self.fit_output = fit_output

# Special order, mode and cval parameters for heatmaps and
# segmentation maps. These may either be None or a fixed value.
# Stochastic parameters are currently *not* supported.
Expand Down Expand Up @@ -2831,6 +2833,20 @@ def _augment_bounding_boxes(self, bounding_boxes_on_images, random_state,
return self._augment_bounding_boxes_as_keypoints(
bounding_boxes_on_images, random_state, parents, hooks)

def _expand_transform(self, M, shape):
imgHeight, imgWidth = shape
rect = np.array([
[0, 0],
[imgWidth - 1, 0],
[imgWidth - 1, imgHeight - 1],
[0, imgHeight - 1]], dtype='float32')
dst = cv2.perspectiveTransform(np.array([rect]), M)[0]
dst -= dst.min(axis=0, keepdims=True)
dst = np.around(dst, decimals=0)
M_expanded = cv2.getPerspectiveTransform(rect, dst)
maxWidth, maxHeight = dst.max(axis=0) + 1
return M_expanded, maxWidth, maxHeight

def _create_matrices(self, shapes, random_state):
# TODO change these to class attributes
mode_str_to_int = {
Expand Down Expand Up @@ -2929,6 +2945,10 @@ def _create_matrices(self, shapes, random_state):

# compute the perspective transform matrix and then apply it
m = cv2.getPerspectiveTransform(points, dst)

if self.fit_output:
m, max_width, max_height = self._expand_transform(m, (h, w))

matrices.append(m)
max_heights.append(max_height)
max_widths.append(max_width)
Expand Down