在从实例分割掩码中提取的二值对象掩码图像中提取感兴趣对象的二值边界图像

Question

I have an instance segmentation + 2D bounding box structure from Detectron 2 from which I converted the pred_masks into a binary object (of interest) mask.

So, here, my question is how can I convert this binary mask to a binary image wherein the entire image is black but the boundary around the object of interest in the object mask is white?

segmenter = get_pointrend_predictor()
instances = segmenter(image)["instances"]
vis = PointRendVisualizer(image, metadata=MetadataCatalog.get("coco_2017_val"))
Image.fromarray(vis.draw_instance_predictions(instances.to("cpu")).get_image())

instances 2 .pred_masks.shape

torch.Size([1, 224, 400])
na = instances[1].pred_masks.to('cpu').numpy()
print(na.shape)

(1, 224, 400)

na = na.reshape(224, 400)
na.shape

(224, 400)

na = np.where(na == False, 0, na)
na = np.where(na == True, 255, na)
plt.imshow(na)

In this specific example, I am interested in drawing a white line on the boundary of the baby elephant (which is my second instance in the instance segmentation mask object).

Unfortunately, I don't have a drawing of the boundary for the baby elephant but here's an example for the boundary of human (shown in white line): ^ image reference: https://www.programmersought.com/article/52814639867/

Answer 1

I just figure out the way to extract edges of a bit mask.

As those depicted in the picture:

na = outputs['instances'][1].pred_masks.to('cpu').numpy()
na = na.reshape(1024, 683)

from detectron2.utils.visualizer import GenericMask
gm = GenericMask(na, 1024, 683)
sg = gm.polygons[0].reshape(-1,2)
print(sg)

By the code I got a list of polygon edges. It's a mask for a balloon.

To verify it, I translated the polygon into JavaScript, as in the following picture, and ran it. Obviously it works.