# Copyright (c) Facebook, Inc. and its affiliates. import atexit import bisect import multiprocessing as mp from collections import deque import cv2 import torch from detectron2.data import MetadataCatalog from detectron2.engine.defaults import DefaultPredictor from detectron2.utils.video_visualizer import VideoVisualizer from detectron2.utils.visualizer import ColorMode, Visualizer class VisualizationDemo: def __init__(self, cfg, instance_mode=ColorMode.IMAGE, parallel=False): """ Args: cfg (CfgNode): instance_mode (ColorMode): parallel (bool): whether to run the model in different processes from visualization. Useful since the visualization logic can be slow. """ self.metadata = MetadataCatalog.get( cfg.DATASETS.TEST[0] if len(cfg.DATASETS.TEST) else "__unused" ) self.cpu_device = torch.device("cpu") self.instance_mode = instance_mode self.parallel = parallel if parallel: num_gpu = torch.cuda.device_count() self.predictor = AsyncPredictor(cfg, num_gpus=num_gpu) else: self.predictor = DefaultPredictor(cfg) def run_on_image(self, image): """ Args: image (np.ndarray): an image of shape (H, W, C) (in BGR order). This is the format used by OpenCV. Returns: predictions (dict): the output of the model. vis_output (VisImage): the visualized image output. """ vis_output = None predictions = self.predictor(image) # Convert image from OpenCV BGR format to Matplotlib RGB format. image = image[:, :, ::-1] visualizer = Visualizer(image, self.metadata, instance_mode=self.instance_mode) if "panoptic_seg" in predictions: panoptic_seg, segments_info = predictions["panoptic_seg"] vis_output = visualizer.draw_panoptic_seg_predictions( panoptic_seg.to(self.cpu_device), segments_info ) else: if "sem_seg" in predictions: vis_output = visualizer.draw_sem_seg( predictions["sem_seg"].argmax(dim=0).to(self.cpu_device) ) if "instances" in predictions: instances = predictions["instances"].to(self.cpu_device) vis_output = visualizer.draw_instance_predictions(predictions=instances) return predictions, vis_output def _frame_from_video(self, video): while video.isOpened(): success, frame = video.read() if success: yield frame else: break def run_on_video(self, video): """ Visualizes predictions on frames of the input video. Args: video (cv2.VideoCapture): a :class:`VideoCapture` object, whose source can be either a webcam or a video file. Yields: ndarray: BGR visualizations of each video frame. """ video_visualizer = VideoVisualizer(self.metadata, self.instance_mode) def process_predictions(frame, predictions): frame = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB) if "panoptic_seg" in predictions: panoptic_seg, segments_info = predictions["panoptic_seg"] vis_frame = video_visualizer.draw_panoptic_seg_predictions( frame, panoptic_seg.to(self.cpu_device), segments_info ) elif "instances" in predictions: predictions = predictions["instances"].to(self.cpu_device) vis_frame = video_visualizer.draw_instance_predictions(frame, predictions) elif "sem_seg" in predictions: vis_frame = video_visualizer.draw_sem_seg( frame, predictions["sem_seg"].argmax(dim=0).to(self.cpu_device) ) # Converts Matplotlib RGB format to OpenCV BGR format vis_frame = cv2.cvtColor(vis_frame.get_image(), cv2.COLOR_RGB2BGR) return vis_frame frame_gen = self._frame_from_video(video) if self.parallel: buffer_size = self.predictor.default_buffer_size frame_data = deque() for cnt, frame in enumerate(frame_gen): frame_data.append(frame) self.predictor.put(frame) if cnt >= buffer_size: frame = frame_data.popleft() predictions = self.predictor.get() yield process_predictions(frame, predictions) while len(frame_data): frame = frame_data.popleft() predictions = self.predictor.get() yield process_predictions(frame, predictions) else: for frame in frame_gen: yield process_predictions(frame, self.predictor(frame)) class AsyncPredictor: """ A predictor that runs the model asynchronously, possibly on >1 GPUs. Because rendering the visualization takes considerably amount of time, this helps improve throughput a little bit when rendering videos. """ class _StopToken: pass class _PredictWorker(mp.Process): def __init__(self, cfg, task_queue, result_queue): self.cfg = cfg self.task_queue = task_queue self.result_queue = result_queue super().__init__() def run(self): predictor = DefaultPredictor(self.cfg) while True: task = self.task_queue.get() if isinstance(task, AsyncPredictor._StopToken): break idx, data = task result = predictor(data) self.result_queue.put((idx, result)) def __init__(self, cfg, num_gpus: int = 1): """ Args: cfg (CfgNode): num_gpus (int): if 0, will run on CPU """ num_workers = max(num_gpus, 1) self.task_queue = mp.Queue(maxsize=num_workers * 3) self.result_queue = mp.Queue(maxsize=num_workers * 3) self.procs = [] for gpuid in range(max(num_gpus, 1)): cfg = cfg.clone() cfg.defrost() cfg.MODEL.DEVICE = "cuda:{}".format(gpuid) if num_gpus > 0 else "cpu" self.procs.append( AsyncPredictor._PredictWorker(cfg, self.task_queue, self.result_queue) ) self.put_idx = 0 self.get_idx = 0 self.result_rank = [] self.result_data = [] for p in self.procs: p.start() atexit.register(self.shutdown) def put(self, image): self.put_idx += 1 self.task_queue.put((self.put_idx, image)) def get(self): self.get_idx += 1 # the index needed for this request if len(self.result_rank) and self.result_rank[0] == self.get_idx: res = self.result_data[0] del self.result_data[0], self.result_rank[0] return res while True: # make sure the results are returned in the correct order idx, res = self.result_queue.get() if idx == self.get_idx: return res insert = bisect.bisect(self.result_rank, idx) self.result_rank.insert(insert, idx) self.result_data.insert(insert, res) def __len__(self): return self.put_idx - self.get_idx def __call__(self, image): self.put(image) return self.get() def shutdown(self): for _ in self.procs: self.task_queue.put(AsyncPredictor._StopToken()) @property def default_buffer_size(self): return len(self.procs) * 5