ultralytics 8.0.127 add FastSAM model (#3390)

Co-authored-by: dingwenchao <12962189468@163.com>
Co-authored-by: 丁文超 <dingwenchao@dingwenchaodeMacBook-Pro.local>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>
Co-authored-by: Ayush Chaurasia <ayush.chaurarsia@gmail.com>

ultralytics/yolo/fastsam/utils.py

@@ -0,0 +1,63 @@
+import torch
+
+
+def adjust_bboxes_to_image_border(boxes, image_shape, threshold=20):
+    '''Adjust bounding boxes to stick to image border if they are within a certain threshold.
+    Args:
+    boxes: (n, 4)
+    image_shape: (height, width)
+    threshold: pixel threshold
+
+    Returns:
+    adjusted_boxes: adjusted bounding boxes
+    '''
+
+    # Image dimensions
+    h, w = image_shape
+
+    # Adjust boxes
+    boxes[:, 0] = torch.where(boxes[:, 0] < threshold, 0, boxes[:, 0])  # x1
+    boxes[:, 1] = torch.where(boxes[:, 1] < threshold, 0, boxes[:, 1])  # y1
+    boxes[:, 2] = torch.where(boxes[:, 2] > w - threshold, w, boxes[:, 2])  # x2
+    boxes[:, 3] = torch.where(boxes[:, 3] > h - threshold, h, boxes[:, 3])  # y2
+
+    return boxes
+
+
+def bbox_iou(box1, boxes, iou_thres=0.9, image_shape=(640, 640), raw_output=False):
+    '''Compute the Intersection-Over-Union of a bounding box with respect to an array of other bounding boxes.
+    Args:
+    box1: (4, )
+    boxes: (n, 4)
+
+    Returns:
+    high_iou_indices: Indices of boxes with IoU > thres
+    '''
+    boxes = adjust_bboxes_to_image_border(boxes, image_shape)
+    # obtain coordinates for intersections
+    x1 = torch.max(box1[0], boxes[:, 0])
+    y1 = torch.max(box1[1], boxes[:, 1])
+    x2 = torch.min(box1[2], boxes[:, 2])
+    y2 = torch.min(box1[3], boxes[:, 3])
+
+    # compute the area of intersection
+    intersection = (x2 - x1).clamp(0) * (y2 - y1).clamp(0)
+
+    # compute the area of both individual boxes
+    box1_area = (box1[2] - box1[0]) * (box1[3] - box1[1])
+    box2_area = (boxes[:, 2] - boxes[:, 0]) * (boxes[:, 3] - boxes[:, 1])
+
+    # compute the area of union
+    union = box1_area + box2_area - intersection
+
+    # compute the IoU
+    iou = intersection / union  # Should be shape (n, )
+    if raw_output:
+        if iou.numel() == 0:
+            return 0
+        return iou
+
+    # get indices of boxes with IoU > thres
+    high_iou_indices = torch.nonzero(iou > iou_thres).flatten()
+
+    return high_iou_indices