exporter: 16bit single-channel network support

ultralytics/engine/exporter.py

@@ -176,7 +176,7 @@ class Exporter:
             raise SystemError('Edge TPU export only supported on Linux. See https://coral.ai/docs/edgetpu/compiler/')
 
         # Input
-        im = torch.zeros(self.args.batch, 3, *self.imgsz).to(self.device)
+        im = torch.zeros(self.args.batch, 1, *self.imgsz).to(self.device)
         file = Path(
             getattr(model, 'pt_path', None) or getattr(model, 'yaml_file', None) or model.yaml.get('yaml_file', ''))
         if file.suffix in ('.yaml', '.yml'):