339 lines
12 KiB
Python
339 lines
12 KiB
Python
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"""yolo_with_plugins.py
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Implementation of TrtYOLO class with the yolo_layer plugins.
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"""
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from __future__ import print_function
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import ctypes
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import numpy as np
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import cv2
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import tensorrt as trt
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import pycuda.driver as cuda
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try:
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ctypes.cdll.LoadLibrary('./plugins/libyolo_layer.so')
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except OSError as e:
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raise SystemExit('ERROR: failed to load ./plugins/libyolo_layer.so. '
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'Did you forget to do a "make" in the "./plugins/" '
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'subdirectory?') from e
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def _preprocess_yolo(img, input_shape, letter_box=False):
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"""Preprocess an image before TRT YOLO inferencing.
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# Args
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img: int8 numpy array of shape (img_h, img_w, 3)
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input_shape: a tuple of (H, W)
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letter_box: boolean, specifies whether to keep aspect ratio and
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create a "letterboxed" image for inference
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# Returns
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preprocessed img: float32 numpy array of shape (3, H, W)
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"""
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if letter_box:
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img_h, img_w, _ = img.shape
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new_h, new_w = input_shape[0], input_shape[1]
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offset_h, offset_w = 0, 0
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if (new_w / img_w) <= (new_h / img_h):
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new_h = int(img_h * new_w / img_w)
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offset_h = (input_shape[0] - new_h) // 2
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else:
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new_w = int(img_w * new_h / img_h)
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offset_w = (input_shape[1] - new_w) // 2
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resized = cv2.resize(img, (new_w, new_h))
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img = np.full((input_shape[0], input_shape[1], 3), 127, dtype=np.uint8)
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img[offset_h:(offset_h + new_h), offset_w:(offset_w + new_w), :] = resized
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else:
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img = cv2.resize(img, (input_shape[1], input_shape[0]))
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img = cv2.cvtColor(img, cv2.COLOR_BGR2RGB)
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img = img.transpose((2, 0, 1)).astype(np.float32)
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img /= 255.0
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return img
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def _nms_boxes(detections, nms_threshold):
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"""Apply the Non-Maximum Suppression (NMS) algorithm on the bounding
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boxes with their confidence scores and return an array with the
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indexes of the bounding boxes we want to keep.
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# Args
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detections: Nx7 numpy arrays of
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[[x, y, w, h, box_confidence, class_id, class_prob],
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......]
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"""
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x_coord = detections[:, 0]
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y_coord = detections[:, 1]
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width = detections[:, 2]
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height = detections[:, 3]
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box_confidences = detections[:, 4] * detections[:, 6]
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areas = width * height
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ordered = box_confidences.argsort()[::-1]
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keep = list()
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while ordered.size > 0:
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# Index of the current element:
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i = ordered[0]
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keep.append(i)
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xx1 = np.maximum(x_coord[i], x_coord[ordered[1:]])
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yy1 = np.maximum(y_coord[i], y_coord[ordered[1:]])
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xx2 = np.minimum(x_coord[i] + width[i], x_coord[ordered[1:]] + width[ordered[1:]])
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yy2 = np.minimum(y_coord[i] + height[i], y_coord[ordered[1:]] + height[ordered[1:]])
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width1 = np.maximum(0.0, xx2 - xx1 + 1)
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height1 = np.maximum(0.0, yy2 - yy1 + 1)
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intersection = width1 * height1
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union = (areas[i] + areas[ordered[1:]] - intersection)
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iou = intersection / union
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indexes = np.where(iou <= nms_threshold)[0]
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ordered = ordered[indexes + 1]
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keep = np.array(keep)
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return keep
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def _postprocess_yolo(trt_outputs, img_w, img_h, conf_th, nms_threshold,
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input_shape, letter_box=False):
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"""Postprocess TensorRT outputs.
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# Args
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trt_outputs: a list of 2 or 3 tensors, where each tensor
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contains a multiple of 7 float32 numbers in
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the order of [x, y, w, h, box_confidence, class_id, class_prob]
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conf_th: confidence threshold
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letter_box: boolean, referring to _preprocess_yolo()
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# Returns
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boxes, scores, classes (after NMS)
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"""
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# filter low-conf detections and concatenate results of all yolo layers
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detections = []
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for o in trt_outputs:
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dets = o.reshape((-1, 7))
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dets = dets[dets[:, 4] * dets[:, 6] >= conf_th]
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detections.append(dets)
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detections = np.concatenate(detections, axis=0)
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if len(detections) == 0:
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boxes = np.zeros((0, 4), dtype=np.int)
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scores = np.zeros((0,), dtype=np.float32)
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classes = np.zeros((0,), dtype=np.float32)
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else:
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box_scores = detections[:, 4] * detections[:, 6]
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# scale x, y, w, h from [0, 1] to pixel values
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old_h, old_w = img_h, img_w
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offset_h, offset_w = 0, 0
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if letter_box:
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if (img_w / input_shape[1]) >= (img_h / input_shape[0]):
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old_h = int(input_shape[0] * img_w / input_shape[1])
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offset_h = (old_h - img_h) // 2
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else:
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old_w = int(input_shape[1] * img_h / input_shape[0])
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offset_w = (old_w - img_w) // 2
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detections[:, 0:4] *= np.array(
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[old_w, old_h, old_w, old_h], dtype=np.float32)
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# NMS
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nms_detections = np.zeros((0, 7), dtype=detections.dtype)
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for class_id in set(detections[:, 5]):
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idxs = np.where(detections[:, 5] == class_id)
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cls_detections = detections[idxs]
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keep = _nms_boxes(cls_detections, nms_threshold)
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nms_detections = np.concatenate(
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[nms_detections, cls_detections[keep]], axis=0)
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xx = nms_detections[:, 0].reshape(-1, 1)
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yy = nms_detections[:, 1].reshape(-1, 1)
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if letter_box:
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xx = xx - offset_w
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yy = yy - offset_h
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ww = nms_detections[:, 2].reshape(-1, 1)
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hh = nms_detections[:, 3].reshape(-1, 1)
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boxes = np.concatenate([xx, yy, xx+ww, yy+hh], axis=1) + 0.5
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boxes = boxes.astype(np.int)
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scores = nms_detections[:, 4] * nms_detections[:, 6]
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classes = nms_detections[:, 5]
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return boxes, scores, classes
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class HostDeviceMem(object):
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"""Simple helper data class that's a little nicer to use than a 2-tuple."""
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def __init__(self, host_mem, device_mem):
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self.host = host_mem
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self.device = device_mem
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def __str__(self):
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return "Host:\n" + str(self.host) + "\nDevice:\n" + str(self.device)
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def __repr__(self):
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return self.__str__()
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def __del__(self):
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del self.device
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del self.host
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def get_input_shape(engine):
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"""Get input shape of the TensorRT YOLO engine."""
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binding = engine[0]
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assert engine.binding_is_input(binding)
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binding_dims = engine.get_binding_shape(binding)
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if len(binding_dims) == 4:
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return tuple(binding_dims[2:])
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elif len(binding_dims) == 3:
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return tuple(binding_dims[1:])
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else:
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raise ValueError('bad dims of binding %s: %s' % (binding, str(binding_dims)))
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def allocate_buffers(engine):
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"""Allocates all host/device in/out buffers required for an engine."""
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inputs = []
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outputs = []
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bindings = []
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output_idx = 0
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stream = cuda.Stream()
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for binding in engine:
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binding_dims = engine.get_binding_shape(binding)
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if len(binding_dims) == 4:
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# explicit batch case (TensorRT 7+)
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size = trt.volume(binding_dims)
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elif len(binding_dims) == 3:
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# implicit batch case (TensorRT 6 or older)
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size = trt.volume(binding_dims) * engine.max_batch_size
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else:
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raise ValueError('bad dims of binding %s: %s' % (binding, str(binding_dims)))
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dtype = trt.nptype(engine.get_binding_dtype(binding))
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# Allocate host and device buffers
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host_mem = cuda.pagelocked_empty(size, dtype)
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device_mem = cuda.mem_alloc(host_mem.nbytes)
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# Append the device buffer to device bindings.
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bindings.append(int(device_mem))
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# Append to the appropriate list.
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if engine.binding_is_input(binding):
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inputs.append(HostDeviceMem(host_mem, device_mem))
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else:
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# each grid has 3 anchors, each anchor generates a detection
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# output of 7 float32 values
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assert size % 7 == 0
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outputs.append(HostDeviceMem(host_mem, device_mem))
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output_idx += 1
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assert len(inputs) == 1
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assert len(outputs) == 1
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return inputs, outputs, bindings, stream
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def do_inference(context, bindings, inputs, outputs, stream, batch_size=1):
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"""do_inference (for TensorRT 6.x or lower)
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This function is generalized for multiple inputs/outputs.
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Inputs and outputs are expected to be lists of HostDeviceMem objects.
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"""
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# Transfer input data to the GPU.
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[cuda.memcpy_htod_async(inp.device, inp.host, stream) for inp in inputs]
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# Run inference.
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context.execute_async(batch_size=batch_size,
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bindings=bindings,
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stream_handle=stream.handle)
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# Transfer predictions back from the GPU.
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[cuda.memcpy_dtoh_async(out.host, out.device, stream) for out in outputs]
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# Synchronize the stream
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stream.synchronize()
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# Return only the host outputs.
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return [out.host for out in outputs]
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def do_inference_v2(context, bindings, inputs, outputs, stream):
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"""do_inference_v2 (for TensorRT 7.0+)
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This function is generalized for multiple inputs/outputs for full
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dimension networks.
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Inputs and outputs are expected to be lists of HostDeviceMem objects.
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"""
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# Transfer input data to the GPU.
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[cuda.memcpy_htod_async(inp.device, inp.host, stream) for inp in inputs]
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# Run inference.
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context.execute_async_v2(bindings=bindings, stream_handle=stream.handle)
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# Transfer predictions back from the GPU.
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[cuda.memcpy_dtoh_async(out.host, out.device, stream) for out in outputs]
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# Synchronize the stream
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stream.synchronize()
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# Return only the host outputs.
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return [out.host for out in outputs]
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class TrtYOLO(object):
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"""TrtYOLO class encapsulates things needed to run TRT YOLO."""
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def _load_engine(self):
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TRTbin = 'yolo/%s.trt' % self.model
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with open(TRTbin, 'rb') as f, trt.Runtime(self.trt_logger) as runtime:
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return runtime.deserialize_cuda_engine(f.read())
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def __init__(self, model, category_num=80, letter_box=False, cuda_ctx=None):
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"""Initialize TensorRT plugins, engine and conetxt."""
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self.model = model
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self.category_num = category_num
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self.letter_box = letter_box
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self.cuda_ctx = cuda_ctx
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if self.cuda_ctx:
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self.cuda_ctx.push()
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self.inference_fn = do_inference if trt.__version__[0] < '7' \
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else do_inference_v2
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self.trt_logger = trt.Logger(trt.Logger.INFO)
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self.engine = self._load_engine()
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self.input_shape = get_input_shape(self.engine)
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try:
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self.context = self.engine.create_execution_context()
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self.inputs, self.outputs, self.bindings, self.stream = \
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allocate_buffers(self.engine)
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except Exception as e:
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raise RuntimeError('fail to allocate CUDA resources') from e
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finally:
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if self.cuda_ctx:
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self.cuda_ctx.pop()
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def __del__(self):
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"""Free CUDA memories."""
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del self.outputs
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del self.inputs
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del self.stream
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def detect(self, img, conf_th=0.3, letter_box=None):
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"""Detect objects in the input image."""
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letter_box = self.letter_box if letter_box is None else letter_box
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img_resized = _preprocess_yolo(img, self.input_shape, letter_box)
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# Set host input to the image. The do_inference() function
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# will copy the input to the GPU before executing.
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self.inputs[0].host = np.ascontiguousarray(img_resized)
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if self.cuda_ctx:
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self.cuda_ctx.push()
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trt_outputs = self.inference_fn(
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context=self.context,
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bindings=self.bindings,
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inputs=self.inputs,
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outputs=self.outputs,
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stream=self.stream)
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if self.cuda_ctx:
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self.cuda_ctx.pop()
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boxes, scores, classes = _postprocess_yolo(
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trt_outputs, img.shape[1], img.shape[0], conf_th,
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nms_threshold=0.5, input_shape=self.input_shape,
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letter_box=letter_box)
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# clip x1, y1, x2, y2 within original image
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boxes[:, [0, 2]] = np.clip(boxes[:, [0, 2]], 0, img.shape[1]-1)
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boxes[:, [1, 3]] = np.clip(boxes[:, [1, 3]], 0, img.shape[0]-1)
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return boxes, scores, classes
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