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import numpy as np |
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import cv2 |
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class YoloX: |
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def __init__(self, modelPath, confThreshold=0.35, nmsThreshold=0.5, objThreshold=0.5, backendId=0, targetId=0): |
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self.num_classes = 80 |
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self.net = cv2.dnn.readNet(modelPath) |
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self.input_size = (640, 640) |
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self.mean = np.array([0.485, 0.456, 0.406], dtype=np.float32).reshape(1, 1, 3) |
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self.std = np.array([0.229, 0.224, 0.225], dtype=np.float32).reshape(1, 1, 3) |
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self.strides = [8, 16, 32] |
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self.confThreshold = confThreshold |
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self.nmsThreshold = nmsThreshold |
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self.objThreshold = objThreshold |
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self.backendId = backendId |
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self.targetId = targetId |
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self.net.setPreferableBackend(self.backendId) |
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self.net.setPreferableTarget(self.targetId) |
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self.generateAnchors() |
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@property |
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def name(self): |
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return self.__class__.__name__ |
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def setBackendAndTarget(self, backendId, targetId): |
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self.backendId = backendId |
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self.targetId = targetId |
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self.net.setPreferableBackend(self.backendId) |
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self.net.setPreferableTarget(self.targetId) |
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def preprocess(self, img): |
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blob = np.transpose(img, (2, 0, 1)) |
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return blob[np.newaxis, :, :, :] |
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def infer(self, srcimg): |
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input_blob = self.preprocess(srcimg) |
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self.net.setInput(input_blob) |
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outs = self.net.forward(self.net.getUnconnectedOutLayersNames()) |
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predictions = self.postprocess(outs[0]) |
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return predictions |
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def postprocess(self, outputs): |
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dets = outputs[0] |
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dets[:, :2] = (dets[:, :2] + self.grids) * self.expanded_strides |
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dets[:, 2:4] = np.exp(dets[:, 2:4]) * self.expanded_strides |
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boxes = dets[:, :4] |
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boxes_xyxy = np.ones_like(boxes) |
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boxes_xyxy[:, 0] = boxes[:, 0] - boxes[:, 2] / 2. |
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boxes_xyxy[:, 1] = boxes[:, 1] - boxes[:, 3] / 2. |
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boxes_xyxy[:, 2] = boxes[:, 0] + boxes[:, 2] / 2. |
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boxes_xyxy[:, 3] = boxes[:, 1] + boxes[:, 3] / 2. |
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scores = dets[:, 4:5] * dets[:, 5:] |
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max_scores = np.amax(scores, axis=1) |
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max_scores_idx = np.argmax(scores, axis=1) |
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keep = cv2.dnn.NMSBoxesBatched(boxes_xyxy.tolist(), max_scores.tolist(), max_scores_idx.tolist(), self.confThreshold, self.nmsThreshold) |
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candidates = np.concatenate([boxes_xyxy, max_scores[:, None], max_scores_idx[:, None]], axis=1) |
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if len(keep) == 0: |
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return np.array([]) |
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return candidates[keep] |
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def generateAnchors(self): |
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self.grids = [] |
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self.expanded_strides = [] |
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hsizes = [self.input_size[0] // stride for stride in self.strides] |
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wsizes = [self.input_size[1] // stride for stride in self.strides] |
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for hsize, wsize, stride in zip(hsizes, wsizes, self.strides): |
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xv, yv = np.meshgrid(np.arange(hsize), np.arange(wsize)) |
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grid = np.stack((xv, yv), 2).reshape(1, -1, 2) |
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self.grids.append(grid) |
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shape = grid.shape[:2] |
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self.expanded_strides.append(np.full((*shape, 1), stride)) |
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self.grids = np.concatenate(self.grids, 1) |
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self.expanded_strides = np.concatenate(self.expanded_strides, 1) |
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