Add support for image batch processing

May I inquire if the author has implemented batch processing for multiple images? It appears that the current detector's `__call__` function only allows for inference on a single image.
```python
class CannyDetector:
def __call__(self, input_image=None, low_threshold=100, high_threshold=200, detect_resolution=512, image_resolution=512, output_type=None, **kwargs):
```