add script of check dataset information

Author: CoinCheung

README.md

@@ -109,6 +109,10 @@ frankfurt_000001_079206_leftImg8bit.png,frankfurt_000001_079206_gtFine_labelIds.
 ...
 ```
 Each line is a pair of training sample and ground truth image path, which are separated by a single comma `,`.   
+I recommand you to check the information of your dataset with the script:  
+```
+$ python tools/check_dataset_info.py --im_root /path/to/your/data_root --im_anns /path/to/your/anno_file
+```
 Then you need to change the field of `im_root` and `train/val_im_anns` in the config file. I prepared a demo config file for you named [`bisenet_customer.py`](./configs/bisenet_customer.py). You can start from this conig file.
 
 

tools/check_dataset_info.py

@@ -0,0 +1,112 @@
+
+import os
+import os.path as osp
+import argparse
+from tqdm import tqdm
+
+import cv2
+import numpy as np
+
+
+parse = argparse.ArgumentParser()
+parse.add_argument('--im_root', dest='im_root', type=str, default='./datasets/cityscapes',)
+parse.add_argument('--im_anns', dest='im_anns', type=str, default='./datasets/cityscapes/train.txt',)
+args = parse.parse_args()
+
+
+with open(args.im_anns, 'r') as fr:
+    lines = fr.read().splitlines()
+
+n_pairs = len(lines)
+impaths, lbpaths = [], []
+for l in lines:
+    impth, lbpth = l.split(',')
+    impth = osp.join(args.im_root, impth)
+    lbpth = osp.join(args.im_root, lbpth)
+    impaths.append(impth)
+    lbpaths.append(lbpth)
+
+
+## shapes
+max_shape_area, min_shape_area = [0, 0], [100000, 100000]
+max_shape_height, min_shape_height = [0, 0], [100000, 100000]
+max_shape_width, min_shape_width = [0, 0], [100000, 100000]
+max_lb_val, min_lb_val = -1, 10000000
+for impth, lbpth in tqdm(zip(impaths, lbpaths), total=n_pairs):
+    im = cv2.imread(impth)[:, :, ::-1]
+    lb = cv2.imread(lbpth, 0)
+    assert im.shape[:2] == lb.shape
+
+    shape = lb.shape
+    area = shape[0] * shape[1]
+    if area > max_shape_area[0] * max_shape_area[1]:
+        max_shape_area = shape
+    if area < min_shape_area[0] * min_shape_area[1]:
+        min_shape_area = shape
+
+    if shape[0] > max_shape_height[0]:
+        max_shape_height = shape
+    if shape[0] < min_shape_height[0]:
+        min_shape_height = shape
+
+    if shape[1] > max_shape_width[1]:
+        max_shape_width = shape
+    if shape[1] < min_shape_width[1]:
+        min_shape_width = shape
+
+    max_lb_val = max(max_lb_val, np.max(lb.ravel()))
+    min_lb_val = min(min_lb_val, np.min(lb.ravel()))
+
+
+## label info
+lb_minlength = max_lb_val+1-min_lb_val
+lb_hist = np.zeros(lb_minlength)
+for impth in tqdm(impaths):
+    lb = cv2.imread(lbpth, 0).ravel() + min_lb_val
+    lb_hist += np.bincount(lb, minlength=lb_minlength)
+
+lb_missing_vals = [ind + min_lb_val
+        for ind, el in enumerate(lb_hist.tolist()) if el == 0]
+lb_ratios = (lb_hist / lb_hist.sum()).tolist()
+
+
+## pixel mean/std
+rgb_mean = np.zeros(3).astype(np.float32)
+n_pixels = 0
+for impth in tqdm(impaths):
+    im = cv2.imread(impth)[:, :, ::-1].astype(np.float32)
+    im = im.reshape(-1, 3)
+    n_pixels += im.shape[0]
+    rgb_mean += im.sum(axis=0)
+rgb_mean = rgb_mean / n_pixels
+
+rgb_std = np.zeros(3).astype(np.float32)
+for impth in tqdm(impaths):
+    im = cv2.imread(impth)[:, :, ::-1].astype(np.float32)
+    im = im.reshape(-1, 3)
+
+    a = (im - rgb_mean.reshape(1, 3)) ** 2
+    rgb_std += a.sum(axis=0)
+rgb_std = (rgb_std / n_pixels) ** (0.5)
+
+
+print(f'there are {n_pairs} lines in {args.im_anns}, which means {n_pairs} image/label image pairs')
+print('\n')
+
+print('max and min image shapes by area are: ')
+print(f'\t{max_shape_area}, {min_shape_area}')
+print('max and min image shapes by height are: ')
+print(f'\t{max_shape_height}, {min_shape_height}')
+print('max and min image shapes by width are: ')
+print(f'\t{max_shape_width}, {min_shape_width}')
+print('\n')
+
+print(f'label values are within range of ({min_lb_val}, {max_lb_val})')
+print('label values that are missing: ')
+print('\t', lb_missing_vals)
+print('ratios of each label value: ')
+print('\t', lb_ratios)
+print('\n')
+
+print('pixel mean rgb: ', mean)
+print('pixel std rgb: ', std)