class ShapesDataset(utils.Dataset):
"""Generates the shapes synthetic dataset. The dataset consists of simple
shapes (triangles, squares, circles) placed randomly on a blank surface.
The images are generated on the fly. No file access required.
"""
def load_shapes(self, count, height, width):
"""Generate the requested number of synthetic images.
count: number of images to generate.
height, width: the size of the generated images.
"""
self.add_class("shapes", 1, "square")
self.add_class("shapes", 2, "circle")
self.add_class("shapes", 3, "triangle")
for i in range(count):
bg_color, shapes = self.random_image(height, width)
self.add_image("shapes", image_id=i, path=None,
width=width, height=height,
bg_color=bg_color, shapes=shapes)
def load_image(self, image_id):
"""Generate an image from the specs of the given image ID.
Typically this function loads the image from a file, but
in this case it generates the image on the fly from the
specs in image_info.
"""
info = self.image_info[image_id]
bg_color = np.array(info['bg_color']).reshape([1, 1, 3])
image = np.ones([info['height'], info['width'], 3], dtype=np.uint8)
image = image * bg_color.astype(np.uint8)
for shape, color, dims in info['shapes']:
image = self.draw_shape(image, shape, dims, color)
return image
def image_reference(self, image_id):
"""Return the shapes data of the image."""
info = self.image_info[image_id]
if info["source"] == "shapes":
return info["shapes"]
else:
super(self.__class__).image_reference(self, image_id)
def load_mask(self, image_id):
"""Generate instance masks for shapes of the given image ID.
"""
info = self.image_info[image_id]
shapes = info['shapes']
count = len(shapes)
mask = np.zeros([info['height'], info['width'], count], dtype=np.uint8)
for i, (shape, _, dims) in enumerate(info['shapes']):
mask[:, :, i:i+1] = self.draw_shape(mask[:, :, i:i+1].copy(),
shape, dims, 1)
occlusion = np.logical_not(mask[:, :, -1]).astype(np.uint8)
for i in range(count-2, -1, -1):
mask[:, :, i] = mask[:, :, i] * occlusion
occlusion = np.logical_and(occlusion, np.logical_not(mask[:, :, i]))
class_ids = np.array([self.class_names.index(s[0]) for s in shapes])
return mask.astype(np.bool), class_ids.astype(np.int32)
def draw_shape(self, image, shape, dims, color):
"""Draws a shape from the given specs."""
x, y, s = dims
if shape == 'square':
cv2.rectangle(image, (x-s, y-s), (x+s, y+s), color, -1)
elif shape == "circle":
cv2.circle(image, (x, y), s, color, -1)
elif shape == "triangle":
points = np.array([[(x, y-s),
(x-s/math.sin(math.radians(60)), y+s),
(x+s/math.sin(math.radians(60)), y+s),
]], dtype=np.int32)
cv2.fillPoly(image, points, color)
return image
def random_shape(self, height, width):
"""Generates specifications of a random shape that lies within
the given height and width boundaries.
Returns a tuple of three valus:
* The shape name (square, circle, ...)
* Shape color: a tuple of 3 values, RGB.
* Shape dimensions: A tuple of values that define the shape size
and location. Differs per shape type.
"""
shape = random.choice(["square", "circle", "triangle"])
color = tuple([random.randint(0, 255) for _ in range(3)])
buffer = 20
y = random.randint(buffer, height - buffer - 1)
x = random.randint(buffer, width - buffer - 1)
s = random.randint(buffer, height//4)
return shape, color, (x, y, s)
def random_image(self, height, width):
"""Creates random specifications of an image with multiple shapes.
Returns the background color of the image and a list of shape
specifications that can be used to draw the image.
"""
bg_color = np.array([random.randint(0, 255) for _ in range(3)])
shapes = []
boxes = []
N = random.randint(1, 4)
for _ in range(N):
shape, color, dims = self.random_shape(height, width)
shapes.append((shape, color, dims))
x, y, s = dims
boxes.append([y-s, x-s, y+s, x+s])
keep_ixs = utils.non_max_suppression(np.array(boxes), np.arange(N), 0.3)
shapes = [s for i, s in enumerate(shapes) if i in keep_ixs]
return bg_color, shapes