initial check-in of DetectNet training guide

tools/coco2kitti.py

@@ -0,0 +1,68 @@
+"""coco2kitti.py: Converts MS COCO annotation files to
+                  Kitti format bounding box label files
+__author__ = "Jon Barker"
+"""
+
+import os
+from pycocotools.coco import COCO
+
+def coco2kitti(catNms, annFile):
+
+    # initialize COCO api for instance annotations
+    coco = COCO(annFile)
+
+    # Create an index for the category names
+    cats = coco.loadCats(coco.getCatIds())
+    cat_idx = {}
+    for c in cats:
+        cat_idx[c['id']] = c['name']
+
+    for img in coco.imgs:
+
+        # Get all annotation IDs for the image
+        catIds = coco.getCatIds(catNms=catNms)
+        annIds = coco.getAnnIds(imgIds=[img], catIds=catIds)
+
+        # If there are annotations, create a label file
+        if len(annIds) > 0:
+            # Get image filename
+            img_fname = coco.imgs[img]['file_name']
+            # open text file
+            with open('./labels/' + img_fname.split('.')[0] + '.txt','w') as label_file:
+                anns = coco.loadAnns(annIds)
+                for a in anns:
+                    bbox = a['bbox']
+                    # Convert COCO bbox coords to Kitti ones
+                    bbox = [bbox[0], bbox[1], bbox[2] + bbox[0], bbox[3] + bbox[1]]
+                    bbox = [str(b) for b in bbox]
+                    catname = cat_idx[a['category_id']]
+                    # Format line in label file
+                    # Note: all whitespace will be removed from class names
+                    out_str = [catname.replace(" ","")
+                               + ' ' + ' '.join(['0']*3)
+                               + ' ' + ' '.join([b for b in bbox])
+                               + ' ' + ' '.join(['0']*8)
+                               +'\n']
+                    label_file.write(out_str[0])
+
+if __name__ == '__main__':
+
+    # These settings assume this script is in the annotations directory
+    dataDir = '..'
+    dataType = 'train2014'
+    annFile = '%s/annotations/instances_%s.json' % (dataDir, dataType)
+
+    # If this list is populated then label files will only be produced
+    # for images containing the listed classes and only the listed classes
+    # will be in the label file
+    # EXAMPLE:
+    #catNms = ['person', 'dog', 'skateboard']
+    catNms = []
+
+    # Check if a labels file exists and, if not, make one
+    # If it exists already, exit to avoid overwriting
+    if os.path.isdir('./labels'):
+        print('Labels folder already exists - exiting to prevent badness')
+    else:
+        os.mkdir('./labels')
+        coco2kitti(catNms, annFile)