coorected calculation of xc parameter

nms.py

@@ -55,8 +55,8 @@ def non_max_suppresion_v8(prediction, conf_thres=0.25, iou_thres=0.45, classes=N
                         labels=(), max_det=300):
     # TODO: Test this for changed parameter number in yolov8!!! All that could be detected with last commit were persons!
 
-    nc = prediction.shape[2] - 5  # number of classes
-    xc = prediction[..., 4] > conf_thres  # candidates
+    nc = prediction.shape[2] - 4  # number of classes
+    xc = np.amax(prediction[..., 4:], axis=2, keepdims=True) > conf_thres
 
     # Checks
     assert 0 <= conf_thres <= 1, f'Invalid Confidence threshold {conf_thres}, valid values are between 0.0 and 1.0'