AI-Mask conversion

[GeoGBo]

Dear all,
I just started working with labelme. I really like it so much.
Unfortunately, I started creating AI-Masks instead of AI-Polygons. In the JSON file, AI-Mask coordinates do not appear as plain text. Is there a possibility to convert these mask shape types into polygon shape types, where coordinates are available as plain text?
Best regards and many thanks in advance,
GeoGBO

[wkentaro]

@GeoGBo Do you want to get an image mask from shape_type="mask" annotation?
If so, this Twitter thread https://x.com/labelmeai/status/1737781486596833502 would help.

If you want to convert shape_type="mask" to "polygon", you can use this function:

labelme/labelme/ai/_utils.py

Lines 14 to 38 in 3a1f655

	def compute_polygon_from_mask(mask):
	contours = skimage.measure.find_contours(np.pad(mask, pad_width=1))
	if len(contours) == 0:
	logger.warning("No contour found, so returning empty polygon.")
	return np.empty((0, 2), dtype=np.float32)
	contour = max(contours, key=_get_contour_length)
	POLYGON_APPROX_TOLERANCE = 0.004
	polygon = skimage.measure.approximate_polygon(
	coords=contour,
	tolerance=np.ptp(contour, axis=0).max() * POLYGON_APPROX_TOLERANCE,
	)
	polygon = np.clip(polygon, (0, 0), (mask.shape[0] - 1, mask.shape[1] - 1))
	polygon = polygon[:-1] # drop last point that is duplicate of first point
	if 0:
	import PIL.Image
	image_pil = PIL.Image.fromarray(imgviz.gray2rgb(imgviz.bool2ubyte(mask)))
	imgviz.draw.line_(image_pil, yx=polygon, fill=(0, 255, 0))
	for point in polygon:
	imgviz.draw.circle_(image_pil, center=point, diameter=10, fill=(0, 255, 0))
	imgviz.io.imsave("contour.jpg", np.asarray(image_pil))
	return polygon[:, ::-1] # yx -> xy

[GeoGBo]

Great, I followed the Twitter thread, it worked! Thank you so much! 👍