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facebookresearch / segment-anything

The repository provides code for running inference with the SegmentAnything Model (SAM), links for downloading the trained model checkpoints, and example notebooks that show how to use the model.
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could you please explain what are the role of crop_overlap_ratio and crop_n_points_downscale_factor parameters? #750

Open jetsonwork opened 5 months ago

jetsonwork commented 5 months ago

Hi, could you please explain what are the role of crop_overlap_ratio and crop_n_points_downscale_factor parameters? Thanks!

steinkchristensen commented 1 week ago

Here's how crops work:

  1. First the entire image has masks generated for it based on your grid size you declare (32 x 32 for example)
  2. Next, if crop_n_layers > 0, then it will divide the photo into quadrants with the amount of overlap between those quadrants being set as crop_overlap_ratio. This prevents some masks from being missed by two adjacent quadrants.
  3. For each quadrant, it will "zoom into each" for another round of automatic mask generation. crop_n_points_downscale_factor =1 means a 32x32 grid will be used for generating masks in this quadrant. If that is overkill, and you dont need that many points inside a quadrant, you can use for example crop_n_points_downscale_factor=2 which will make the grid 16x16 inside that quadrant.
  4. Crop_NMS determines which masks to keep from the quadrants but I'm not perfectly clear on how that works