class SingleImageViz:
def __init__(
self,
img,
scale=1.2,
edgecolor="g",
alpha=0.5,
linestyle="-",
saveas="test_out.jpg",
rgb=True,
pynb=False,
id2obj=None,
id2attr=None,
pad=0.7,
):
"""
img: an RGB image of shape (H, W, 3).
"""
if isinstance(img, torch.Tensor):
img = img.numpy().astype("np.uint8")
if isinstance(img, str):
img = img_tensorize(img)
assert isinstance(img, np.ndarray)
width, height = img.shape[1], img.shape[0]
fig = mplfigure.Figure(frameon=False)
dpi = fig.get_dpi()
width_in = (width * scale + 1e-2) / dpi
height_in = (height * scale + 1e-2) / dpi
fig.set_size_inches(width_in, height_in)
ax = fig.add_axes([0.0, 0.0, 1.0, 1.0])
ax.axis("off")
ax.set_xlim(0.0, width)
ax.set_ylim(height)
self.saveas = saveas
self.rgb = rgb
self.pynb = pynb
self.img = img
self.edgecolor = edgecolor
self.alpha = 0.5
self.linestyle = linestyle
self.font_size = int(np.sqrt(min(height, width)) * scale // 3)
self.width = width
self.height = height
self.scale = scale
self.fig = fig
self.ax = ax
self.pad = pad
self.id2obj = id2obj
self.id2attr = id2attr
self.canvas = FigureCanvasAgg(fig)
def add_box(self, box, color=None):
if color is None:
color = self.edgecolor
(x0, y0, x1, y1) = box
width = x1 - x0
height = y1 - y0
self.ax.add_patch(
mpl.patches.Rectangle(
(x0, y0),
width,
height,
fill=False,
edgecolor=color,
linewidth=self.font_size // 3,
alpha=self.alpha,
linestyle=self.linestyle,
)
)
def draw_boxes(self, boxes, obj_ids=None, obj_scores=None, attr_ids=None, attr_scores=None):
if len(boxes.shape) > 2:
boxes = boxes[0]
if len(obj_ids.shape) > 1:
obj_ids = obj_ids[0]
if len(obj_scores.shape) > 1:
obj_scores = obj_scores[0]
if len(attr_ids.shape) > 1:
attr_ids = attr_ids[0]
if len(attr_scores.shape) > 1:
attr_scores = attr_scores[0]
if isinstance(boxes, torch.Tensor):
boxes = boxes.numpy()
if isinstance(boxes, list):
boxes = np.array(boxes)
assert isinstance(boxes, np.ndarray)
areas = np.prod(boxes[:, 2:] - boxes[:, :2], axis=1)
sorted_idxs = np.argsort(-areas).tolist()
boxes = boxes[sorted_idxs] if boxes is not None else None
obj_ids = obj_ids[sorted_idxs] if obj_ids is not None else None
obj_scores = obj_scores[sorted_idxs] if obj_scores is not None else None
attr_ids = attr_ids[sorted_idxs] if attr_ids is not None else None
attr_scores = attr_scores[sorted_idxs] if attr_scores is not None else None
assigned_colors = [self._random_color(maximum=1) for _ in range(len(boxes))]
assigned_colors = [assigned_colors[idx] for idx in sorted_idxs]
if obj_ids is not None:
labels = self._create_text_labels_attr(obj_ids, obj_scores, attr_ids, attr_scores)
for i in range(len(boxes)):
color = assigned_colors[i]
self.add_box(boxes[i], color)
self.draw_labels(labels[i], boxes[i], color)
def draw_labels(self, label, box, color):
x0, y0, x1, y1 = box
text_pos = (x0, y0)
instance_area = (y1 - y0) * (x1 - x0)
small = _SMALL_OBJ * self.scale
if instance_area < small or y1 - y0 < 40 * self.scale:
if y1 >= self.height - 5:
text_pos = (x1, y0)
else:
text_pos = (x0, y1)
height_ratio = (y1 - y0) / np.sqrt(self.height * self.width)
lighter_color = self._change_color_brightness(color, brightness_factor=0.7)
font_size = np.clip((height_ratio - 0.02) / 0.08 + 1, 1.2, 2)
font_size *= 0.75 * self.font_size
self.draw_text(
text=label,
position=text_pos,
color=lighter_color,
)
def draw_text(
self,
text,
position,
color="g",
ha="left",
):
rotation = 0
font_size = self.font_size
color = np.maximum(list(mplc.to_rgb(color)), 0.2)
color[np.argmax(color)] = max(0.8, np.max(color))
bbox = {
"facecolor": "black",
"alpha": self.alpha,
"pad": self.pad,
"edgecolor": "none",
}
x, y = position
self.ax.text(
x,
y,
text,
size=font_size * self.scale,
family="sans-serif",
bbox=bbox,
verticalalignment="top",
horizontalalignment=ha,
color=color,
zorder=10,
rotation=rotation,
)
def save(self, saveas=None):
if saveas is None:
saveas = self.saveas
if saveas.lower().endswith(".jpg") or saveas.lower().endswith(".png"):
cv2.imwrite(
saveas,
self._get_buffer()[:, :, ::-1],
)
else:
self.fig.savefig(saveas)
def _create_text_labels_attr(self, classes, scores, attr_classes, attr_scores):
labels = [self.id2obj[i] for i in classes]
attr_labels = [self.id2attr[i] for i in attr_classes]
labels = [
f"{label} {score:.2f} {attr} {attr_score:.2f}"
for label, score, attr, attr_score in zip(labels, scores, attr_labels, attr_scores)
]
return labels
def _create_text_labels(self, classes, scores):
labels = [self.id2obj[i] for i in classes]
if scores is not None:
if labels is None:
labels = ["{:.0f}%".format(s * 100) for s in scores]
else:
labels = ["{} {:.0f}%".format(li, s * 100) for li, s in zip(labels, scores)]
return labels
def _random_color(self, maximum=255):
idx = np.random.randint(0, len(_COLORS))
ret = _COLORS[idx] * maximum
if not self.rgb:
ret = ret[::-1]
return ret
def _get_buffer(self):
if not self.pynb:
s, (width, height) = self.canvas.print_to_buffer()
if (width, height) != (self.width, self.height):
img = cv2.resize(self.img, (width, height))
else:
img = self.img
else:
buf = io.BytesIO() # works for cairo backend
self.canvas.print_rgba(buf)
width, height = self.width, self.height
s = buf.getvalue()
img = self.img
buffer = np.frombuffer(s, dtype="uint8")
img_rgba = buffer.reshape(height, width, 4)
rgb, alpha = np.split(img_rgba, [3], axis=2)
try:
import numexpr as ne # fuse them with numexpr
visualized_image = ne.evaluate("img * (1 - alpha / 255.0) + rgb * (alpha / 255.0)")
except ImportError:
alpha = alpha.astype("float32") / 255.0
visualized_image = img * (1 - alpha) + rgb * alpha
return visualized_image.astype("uint8")
def _change_color_brightness(self, color, brightness_factor):
assert brightness_factor >= -1.0 and brightness_factor <= 1.0
color = mplc.to_rgb(color)
polygon_color = colorsys.rgb_to_hls(*mplc.to_rgb(color))
modified_lightness = polygon_color[1] + (brightness_factor * polygon_color[1])
modified_lightness = 0.0 if modified_lightness < 0.0 else modified_lightness
modified_lightness = 1.0 if modified_lightness > 1.0 else modified_lightness
modified_color = colorsys.hls_to_rgb(polygon_color[0], modified_lightness, polygon_color[2])
return modified_color
