过程记录 yolov3目标检测输出目标坐标和原图物体像素坐标比较

设备：jetsonnano B01 一个usb广角摄像头
语言为python 库为opencv 框架pytorch
大家都知道yolov3的坐标变换过程比较复杂，大概要经过图片缩放，对数空间变换等等，然后在pytorch中是用一个tensor类型来表示张量的，所以一直认为目标检测的坐标是一个奇奇怪怪的值，需要经过变换才能得到原图目标的像素坐标
之前一直纠结怎么坐标转化，但今天实验之后怀疑其实检测结果的坐标转化为int数值以后跟实际原图像素坐标是一样的？
先上结果：
这是原始图片上的坐标点

左下角为像素坐标
（鼠标放在中间油渍的位置时显示的坐标

检测结果：

结果输出的坐标（转化为整数之后输出的）

两个坐标几乎一样，感觉其实它们两个是一个数值，而tensor类型后面多了一串小数点
完整代码
用opencv打开摄像头查看图片某点像素坐标：

import cv2 import os import sys import time import datetime import argparse cap = cv2.VideoCapture(0) i = 1while(cap.isOpened()):ret, frame = cap.read()cv2.imshow('frame',frame)if cv2.waitKey(30) == ord('q'):#ret, frame = cap.read()cv2.imwrite('data/custom/dd/'+str(i)+".jpg",frame) frame=cv2.imread('data/custom/dd/'+str(i)+".jpg")break

检测部分显示结果坐标：
pytorch python

if detections is not None:# Rescale boxes to original imagedetections = rescale_boxes(detections, opt.img_size, img.shape[:2])unique_labels = detections[:, -1].cpu().unique()n_cls_preds = len(unique_labels)bbox_colors = random.sample(colors, n_cls_preds)for x1, y1, x2, y2, conf, cls_conf, cls_pred in detections:print("\t+ Label: %s, Conf: %.5f" % (classes[int(cls_pred)], cls_conf.item())) box_w = x2 - x1box_h = y2 - y1centx = int((x1+x2)*0.1/2)centy = int((y1+y2)*0.1/2)thex.append(centx)they.append(centy)str1+="x:"str1+=str(centx)str1+=",y:"str1+=str(centy)area = int(box_w*0.1)*int(box_h*0.1)if area > 600: time = 30print("x和y"+str((x2+x1)/2)+","+str((y1+y2)/2))print("x:")print(int((x1+x2)/2))print("y:")print(int((y1+y2)/2))print(int(box_w*0.1))print(int(box_h*0.1))color = bbox_colors[int(np.where(unique_labels == int(cls_pred))[0])]# Create a Rectangle patchbbox = patches.Rectangle((x1, y1), box_w, box_h, linewidth=2, edgecolor=color, facecolor="none")print(int(box_w)*int(box_h)*0.01)print(str1)if(box_w*box_h>50):se.write("1".encode())time.sleep(3)se.write("0".encode())se.write(str1.encode())data_read = se.readline()print(data_read.decode())# Add the bbox to the plotax.add_patch(bbox)# Add labelplt.text(x1,y1,s=classes[int(cls_pred)],color="white",verticalalignment="top",bbox={"color": color, "pad": 0},)# Save generated image with detectionsplt.axis("off")plt.gca().xaxis.set_major_locator(NullLocator())plt.gca().yaxis.set_major_locator(NullLocator())filename = os.path.basename(path).split(".")[0]#output_path = os.path.join("output", f"{filename}.png")#output_path = os.path.join("/data/custom/dd", f"{filename}.png")plt.savefig(filename, bbox_inches="tight", pad_inches=0.0)plt.close() if detections is not None:后面的代码是输出坐标的

关于目标检测的完整检测代码：（很长，熟悉的人不必看）

from __future__ import division import serial as ser import time se=ser.Serial("/dev/ttyUSB0",115200,timeout=1) from models import * from utils.utils import * from utils.datasets import * from utils.augmentations import * from utils.transforms import * import cv2 import os import sys import time import datetime import argparsefrom PIL import Imageimport torch import torchvision.transforms as transforms from torch.utils.data import DataLoader from torchvision import datasets from torch.autograd import Variableimport matplotlib.pyplot as plt import matplotlib.patches as patches from matplotlib.ticker import NullLocator i = 1 cap = cv2.VideoCapture(0) array_of_img = [] start = time.time() directory_name=r'output'while(cap.isOpened()):ret, frame = cap.read()cv2.imshow('frame',frame)if cv2.waitKey(30) == ord('q'):#ret, frame = cap.read()cv2.imwrite('data/custom/dd/'+str(i)+".jpg",frame) frame=cv2.imread('data/custom/dd/'+str(i)+".jpg")break # When everything done, release the capturecap.release()cv2.destroyAllWindows()washtime = [] thex = [] they = [] area = 0 str1="" if __name__ == "__main__":parser = argparse.ArgumentParser()parser.add_argument("--image_folder", type=str, default="data/samples", help="path to dataset")parser.add_argument("--model_def", type=str, default="config/yolov3.cfg", help="path to model definition file")parser.add_argument("--weights_path", type=str, default="weights/yolov3.weights", help="path to weights file")parser.add_argument("--class_path", type=str, default="data/coco.names", help="path to class label file")parser.add_argument("--conf_thres", type=float, default=0.8, help="object confidence threshold")parser.add_argument("--nms_thres", type=float, default=0.4, help="iou thresshold for non-maximum suppression")parser.add_argument("--batch_size", type=int, default=1, help="size of the batches")parser.add_argument("--n_cpu", type=int, default=0, help="number of cpu threads to use during batch generation")parser.add_argument("--img_size", type=int, default=416, help="size of each image dimension")parser.add_argument("--checkpoint_model", type=str, help="path to checkpoint model")opt = parser.parse_args()print(opt)device = torch.device("cuda" if torch.cuda.is_available() else "cpu")os.makedirs("output", exist_ok=True)# Set up modellamodel = Darknet(opt.model_def, img_size=opt.img_size).to(device)if opt.weights_path.endswith(".weights"):# Load darknet weightsmodel.load_darknet_weights(opt.weights_path)else:# Load checkpoint weightsmodel.load_state_dict(torch.load(opt.weights_path))model.eval() # Set in evaluation modedataloader = DataLoader(ImageFolder(opt.image_folder, transform= \transforms.Compose([DEFAULT_TRANSFORMS, Resize(opt.img_size)])),batch_size=opt.batch_size,shuffle=False,num_workers=opt.n_cpu,)classes = load_classes(opt.class_path) # Extracts class labels from fileTensor = torch.cuda.FloatTensor if torch.cuda.is_available() else torch.FloatTensorimgs = [] # Stores image pathsimg_detections = [] # Stores detections for each image indexprint("\nPerforming object detection:")prev_time = time.time()for batch_i, (img_paths, input_imgs) in enumerate(dataloader):# Configure inputinput_imgs = Variable(input_imgs.type(Tensor))# Get detectionswith torch.no_grad():detections = model(input_imgs)detections = non_max_suppression(detections, opt.conf_thres, opt.nms_thres)# Log progresscurrent_time = time.time()inference_time = datetime.timedelta(seconds=current_time - prev_time)prev_time = current_timeprint("\t+ Batch %d, Inference Time: %s" % (batch_i, inference_time))# Save image and detectionsimgs.extend(img_paths)img_detections.extend(detections)# Bounding-box colorscmap = plt.get_cmap("tab20b")colors = [cmap(i) for i in np.linspace(0, 1, 20)]print("\nSaving images:")# Iterate through images and save plot of detectionsfor img_i, (path, detections) in enumerate(zip(imgs, img_detections)):print("(%d) Image: '%s'" % (img_i, path))# Create plotimg = np.array(Image.open(path))plt.figure()fig, ax = plt.subplots(1)ax.imshow(img)# Draw bounding boxes and labels of detectionsif detections is not None:# Rescale boxes to original imagedetections = rescale_boxes(detections, opt.img_size, img.shape[:2])unique_labels = detections[:, -1].cpu().unique()n_cls_preds = len(unique_labels)bbox_colors = random.sample(colors, n_cls_preds)for x1, y1, x2, y2, conf, cls_conf, cls_pred in detections:print("\t+ Label: %s, Conf: %.5f" % (classes[int(cls_pred)], cls_conf.item())) box_w = x2 - x1box_h = y2 - y1centx = int((x1+x2)*0.1/2)centy = int((y1+y2)*0.1/2)thex.append(centx)they.append(centy)str1+="x:"str1+=str(centx)str1+=",y:"str1+=str(centy)area = int(box_w*0.1)*int(box_h*0.1)if area > 600: time = 30print("x和y"+str((x2+x1)/2)+","+str((y1+y2)/2))print("x:")print(int((x1+x2)/2))print("y:")print(int((y1+y2)/2))print(int(box_w*0.1))print(int(box_h*0.1))color = bbox_colors[int(np.where(unique_labels == int(cls_pred))[0])]# Create a Rectangle patchbbox = patches.Rectangle((x1, y1), box_w, box_h, linewidth=2, edgecolor=color, facecolor="none")print(int(box_w)*int(box_h)*0.01)print(str1)if(box_w*box_h>50):se.write("1".encode())time.sleep(3)se.write("0".encode())se.write(str1.encode())data_read = se.readline()print(data_read.decode())# Add the bbox to the plotax.add_patch(bbox)# Add labelplt.text(x1,y1,s=classes[int(cls_pred)],color="white",verticalalignment="top",bbox={"color": color, "pad": 0},)# Save generated image with detectionsplt.axis("off")plt.gca().xaxis.set_major_locator(NullLocator())plt.gca().yaxis.set_major_locator(NullLocator())filename = os.path.basename(path).split(".")[0]#output_path = os.path.join("output", f"{filename}.png")#output_path = os.path.join("/data/custom/dd", f"{filename}.png")plt.savefig(filename, bbox_inches="tight", pad_inches=0.0)plt.close()

串口：

se.write("50".encode()) print("缓存中的字节数") print(se.inWaiting()) time.sleep(2) se.write("100".encode()) print("缓存中的字节数") print(se.inWaiting())#：返回接收缓存中的字节数 data = se.readline() print(data.decode()) data = se.readline() print(data.decode()) print(se.inWaiting()) se.write("my87u".encode()) print("缓存中的字节数") print(se.inWaiting()) se.flush() #等待所有数据写出。 data = se.readline() print(data.decode()) data = se.readline() print(data.decode())

参数：

parser = argparse.ArgumentParser()parser.add_argument("--image_folder", type=str, default="data/custom/dd2", help="path to dataset")parser.add_argument("--model_def", type=str, default="config/yolov3-custom.cfg", help="path to model definition file")parser.add_argument("--weights_path", type=str, default="checkpoints/ckpt_86.pth", help="path to weights file")parser.add_argument("--class_path", type=str, default="data/custom/classes.names", help="path to class label file")parser.add_argument("--conf_thres", type=float, default=0.8, help="object confidence threshold")parser.add_argument("--nms_thres", type=float, default=0.4, help="iou thresshold for non-maximum suppression")parser.add_argument("--batch_size", type=int, default=1, help="size of the batches")parser.add_argument("--n_cpu", type=int, default=0, help="number of cpu threads to use during batch generation")parser.add_argument("--img_size", type=int, default=416, help="size of each image dimension")parser.add_argument("--checkpoint_model",type=str,default="checkpoints/ckpt_86.pth", help="path to checkpoint model")opt = parser.parse_args()print(opt)

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