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# Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved | |
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(object): | |
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_RGB2BGR) | |
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 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()) | |
def default_buffer_size(self): | |
return len(self.procs) * 5 | |