How to process a dir of images with SAM and save visualisations of their masks

batch_sam.py

#!/usr/bin/env python
from __future__ import annotations
import os
from pathlib import Path
from segment_anything import sam_model_registry, SamAutomaticMaskGenerator, SamPredictor
import cv2
import numpy as np
import torch
from tqdm import tqdm

# config
in_dir = 'my_images'
out_dir = 'segmented'
sam_model = "vit_l"
sam_check = "sam_vit_l_0b3195.pth"
#sam_model = "vit_h"
#sam_check = "sam_vit_h_4b8939.pth"
#sam_model = "vit_b"
#sam_check = "sam_vit_b_01ec64.pth"
device="cuda"
transparency = 0.3
max_masks = 300

# sam generator params
points_per_batch=64
points_per_side=64
pred_iou_thresh=0.86
stability_score_thresh=0.92
crop_n_layers=1
crop_n_points_downscale_factor=2
min_mask_region_area=100

# list of random colors
colors = []
for i in range(max_masks):
    colors.append(np.random.random((3)))


def draw_segmentation(anns):
    if len(anns) == 0:
        return
    h, w = anns[0]['segmentation'].shape
    image = np.zeros((h, w, 3), dtype=np.float64)
    sorted_anns = sorted(anns, key=(lambda x: x['area']), reverse=True)
    no_masks = min(len(sorted_anns), max_masks)
    for i in range(no_masks):
        # true/false segmentation
        seg = sorted_anns[i]['segmentation']

        # set this segmentation a random color
        image[seg] = colors[i]
    return image


def process_image(img_path, out_path, mask_generator):
    image = cv2.imread(img_path)
    image = cv2.cvtColor(image, cv2.COLOR_BGR2RGB)

    # mask generator wants the default uint8 image
    masks = mask_generator.generate(image)

    # convert to float64
    image = image.astype(np.float64) / 255
    seg = draw_segmentation(masks)

    # add segmentation image on top of original image
    image += transparency * seg

    # convert back to uint8 for display/save
    image = (255 * image).astype(np.uint8)
    image = cv2.cvtColor(image, cv2.COLOR_RGB2BGR)
    # cv2.imshow("my img", image)
    # cv2.waitKey(-1)
    cv2.imwrite(out_path, image)

if __name__ == "__main__":
    # make sure output dir exists
    if not os.path.exists(out_dir):
        os.makedirs(out_dirs)

    # load SAM model + create mask generator
    sam = sam_model_registry[sam_model](checkpoint=sam_check)
    sam.to(device=device)
    sam = torch.compile(sam)
    mask_generator = SamAutomaticMaskGenerator(sam,
                                               points_per_side=points_per_side,
                                               pred_iou_thresh=pred_iou_thresh,
                                               stability_score_thresh=stability_score_thresh,
                                               crop_n_layers=crop_n_layers,
                                               crop_n_points_downscale_factor=crop_n_points_downscale_factor,
                                               min_mask_region_area=min_mask_region_area)
    # process input directory
    for img in tqdm(os.listdir(in_dir)):

        # change extension of output image to .png
        out_img = Path(img).stem + ".png"
        out_img = os.path.join(out_dir, out_img)

        # if we can read/decode this file as an image
        in_img = os.path.join(in_dir, img)
        if cv2.haveImageReader(in_img):
            process_image(in_img, out_img, mask_generator)