Yolov5代码详解——detect.py

首先执行扩展包的导入:

import argparse
import os
import platform
import sys
from pathlib import Path
​
import torch
​
FILE = Path(__file__).resolve()     #获取detect.py在电脑中的绝对路径
ROOT = FILE.parents[0]  # 获取detect.py的父目录(绝对路径)
if str(ROOT) not in sys.path:       # 判断detect.py的父目录是否存在于模块的查询路径列表
    sys.path.append(str(ROOT))  # add ROOT to PATH
ROOT = Path(os.path.relpath(ROOT, Path.cwd()))  # 将绝对路径转换为相对路径
from models.common import DetectMultiBackend
from utils.dataloaders import IMG_FORMATS, VID_FORMATS, LoadImages, LoadScreenshots, LoadStreams
from utils.general import (LOGGER, Profile, check_file, check_img_size, check_imshow, check_requirements, colorstr, cv2,
                           increment_path, non_max_suppression, print_args, scale_boxes, strip_optimizer, xyxy2xywh)
from utils.plots import Annotator, colors, save_one_box
from utils.torch_utils import select_device, smart_inference_mode

包导入完成之后,执行最下面的这段代码:

if __name__ == '__main__':
    opt = parse_opt()       #解析参数
    main(opt)

这段代码用到了parse_opt()这个函数,它的功能主要是解析参数,主要参数解析如下:

"""
--weights:权重的路径地址
--source:测试数据,可以是图片/视频路径,也可以是'0'(电脑自带摄像头),也可以是rtsp等视频流
--output:网络预测之后的图片/视频的保存路径
--img-size:网络输入图片大小
--conf-thres:置信度阈值
--iou-thres:做nms的iou阈值
--device:是用GPU还是CPU做推理
--view-img:是否展示预测之后的图片/视频,默认False
--save-txt:是否将预测的框坐标以txt文件形式保存,默认False
--classes:设置只保留某一部分类别,形如0或者0 2 3
--agnostic-nms:进行nms是否也去除不同类别之间的框,默认False
--augment:推理的时候进行多尺度,翻转等操作(TTA)推理
--update:如果为True,则对所有模型进行strip_optimizer操作,去除pt文件中的优化器等信息,默认为False
--project:推理的结果保存在runs/detect目录下
--name:结果保存的文件夹名称
"""
该部分来源于博主“炮哥带你学”——‘目标检测---教你利用yolov5训练自己的目标检测模型’一文,
原文地址:https://blog.csdn.net/didiaopao/article/details/119954291?spm=1001.2014.3001.5502

在parse_opt()执行完成之后,会将opt传给函数main():

def main(opt):
    check_requirements(exclude=('tensorboard', 'thop'))         #检测中的扩展包是否安装
    run(**vars(opt))

main()函数中调用了函数run(),run()主要代码解析如下:

run()主要分为了六个部分:

  1. 处理预测路径

    #处理预测路径
        source = str(source)    #将路径转为字符串类型(data\\images\\bus.jpg)
        save_img = not nosave and not source.endswith('.txt')  # 保存预测结果
        
        #suffix函数表示文件类型,suffix[1:]表示从.jpg中截取jpg,然后判断jpg是否位于(IMG_FORMATS + VID_FORMATS)中
        is_file = Path(source).suffix[1:] in (IMG_FORMATS + VID_FORMATS)
        
        #判断路径是否为网络流的格式(lower()作用是将字母全部转换为小写)
        is_url = source.lower().startswith(('rtsp://', 'rtmp://', 'http://', 'https://'))
        
        #判断路径是否为‘0’(如果为‘0’会打开电脑摄像头),是否是.streams文件格式,是否是网络流地址
        webcam = source.isnumeric() or source.endswith('.streams') or (is_url and not is_file)
        screenshot = source.lower().startswith('screen')
        
        if is_url and is_file:
            source = check_file(source)  # download,下载图片或视频
  2. 新建保存结果的文件夹

    # Directories,新建保存结果的文件夹
        
        #增量式地产生文件夹(exp,exp1,exp2...)
        save_dir = increment_path(Path(project) / name, exist_ok=exist_ok)  # increment run
        
        #在exp文件夹下新建labels文件夹
        (save_dir / 'labels' if save_txt else save_dir).mkdir(parents=True, exist_ok=True)  # make dir
  3. 加载模型的权重

    # Load model,加载模型的权重
        device = select_device(device)      #选择加载模型的设备
        
        #加载模型并从模型中读取一些信息
        model = DetectMultiBackend(weights, device=device, dnn=dnn, data=data, fp16=half)
        stride, names, pt = model.stride, model.names, model.pt
        
        imgsz = check_img_size(imgsz, s=stride)  # check image size
  4. 加载待预测的图片

    # Dataloader,加载待预测的图片
        bs = 1  # batch_size
        if webcam:          #根据‘处理预测路径’代码部分得webcam一般为false
            view_img = check_imshow(warn=True)
            dataset = LoadStreams(source, img_size=imgsz, stride=stride, auto=pt, vid_stride=vid_stride)
            bs = len(dataset)
        elif screenshot:    #根据‘处理预测路径’代码部分得screenshot一般为false
            dataset = LoadScreenshots(source, img_size=imgsz, stride=stride, auto=pt)
        else:   #加载图片
            dataset = LoadImages(source, img_size=imgsz, stride=stride, auto=pt, vid_stride=vid_stride)
        vid_path, vid_writer = [None] * bs, [None] * bs
  5. 执行模型的推理过程

    # Run inference,执行模型的推理过程
    #warmup初始化一张空白图片并传入到模型当中,让模型执行一次前向传播
        model.warmup(imgsz=(1 if pt or model.triton else bs, 3, *imgsz))  # warmup
        
        seen, windows, dt = 0, [], (Profile(), Profile(), Profile())    #定义变量存储中间结果信息
        
        #path:路径    im:处理后的图片   im0s:原图     vid_cap:none    s:图片的打印信息
        for path, im, im0s, vid_cap, s in dataset:
            with dt[0]:
                im = torch.from_numpy(im).to(model.device)  #将im转化为pytorch支持的格式并放到设备中
                im = im.half() if model.fp16 else im.float()  # uint8 to fp16/32
                im /= 255  # 0 - 255 to 0.0 - 1.0   #归一化
                if len(im.shape) == 3:
                    im = im[None]  # expand for batch dim
    # Inference,对上面整理好的图片进行预测
            with dt[1]:
                visualize = increment_path(save_dir / Path(path).stem, mkdir=True) if visualize else False
                pred = model(im, augment=augment, visualize=visualize)
    ​
            # NMS,进行非极大值过滤
            with dt[2]:
                pred = non_max_suppression(pred, conf_thres, iou_thres, classes, agnostic_nms, max_det=max_det)
    ​
            # Second-stage classifier (optional)
            # pred = utils.general.apply_classifier(pred, classifier_model, im, im0s)
    # Process predictions
            for i, det in enumerate(pred):  # 遍历每张图片
                seen += 1
                if webcam:  # batch_size >= 1
                    p, im0, frame = path[i], im0s[i].copy(), dataset.count
                    s += f'{i}: '
                else:
                    p, im0, frame = path, im0s.copy(), getattr(dataset, 'frame', 0)
    ​
                p = Path(p)  # to Path
                save_path = str(save_dir / p.name)  # im.jpg
                txt_path = str(save_dir / 'labels' / p.stem) + ('' if dataset.mode == 'image' else f'_{frame}')  # im.txt
                s += '%gx%g ' % im.shape[2:]  # print string
                gn = torch.tensor(im0.shape)[[1, 0, 1, 0]]  #获取原图宽和高
                imc = im0.copy() if save_crop else im0  #判断是否将检测框部分裁剪下来
                annotator = Annotator(im0, line_width=line_thickness, example=str(names))   #定义绘图工具
                if len(det):
                    #坐标映射,方便在原图上画检测框
                    det[:, :4] = scale_boxes(im.shape[2:], det[:, :4], im0.shape).round()
    ​
                    # 遍历det
                    for c in det[:, 5].unique():
                        n = (det[:, 5] == c).sum()  # detections per class
                        s += f"{n} {names[int(c)]}{'s' * (n > 1)}, "  # add to string
    # 是否保存预测结果
                    for *xyxy, conf, cls in reversed(det):
                        if save_txt:  # 保存为txt
                            xywh = (xyxy2xywh(torch.tensor(xyxy).view(1, 4)) / gn).view(-1).tolist()  # normalized xywh
                            line = (cls, *xywh, conf) if save_conf else (cls, *xywh)  # label format
                            with open(f'{txt_path}.txt', 'a') as f:
                                f.write(('%g ' * len(line)).rstrip() % line + '\n')
    ​
                        if save_img or save_crop or view_img:  # 只在图片上添加检测框
                            c = int(cls)  # integer class
                            label = None if hide_labels else (names[c] if hide_conf else f'{names[c]} {conf:.2f}')
                            annotator.box_label(xyxy, label, color=colors(c, True))
                        if save_crop:   #是否保存截下来的目标框
                            save_one_box(xyxy, imc, file=save_dir / 'crops' / names[c] / f'{p.stem}.jpg', BGR=True)
    ​
                # Stream results
                im0 = annotator.result()
                if view_img:
                    if platform.system() == 'Linux' and p not in windows:
                        windows.append(p)
                        cv2.namedWindow(str(p), cv2.WINDOW_NORMAL | cv2.WINDOW_KEEPRATIO)  # allow window resize (Linux)
                        cv2.resizeWindow(str(p), im0.shape[1], im0.shape[0])
                    cv2.imshow(str(p), im0)
                    cv2.waitKey(1)  # 1 millisecond
    # Save results (image with detections)
                if save_img:
                    if dataset.mode == 'image':
                        cv2.imwrite(save_path, im0)
                    else:  # 'video' or 'stream'
                        if vid_path[i] != save_path:  # new video
                            vid_path[i] = save_path
                            if isinstance(vid_writer[i], cv2.VideoWriter):
                                vid_writer[i].release()  # release previous video writer
                            if vid_cap:  # video
                                fps = vid_cap.get(cv2.CAP_PROP_FPS)
                                w = int(vid_cap.get(cv2.CAP_PROP_FRAME_WIDTH))
                                h = int(vid_cap.get(cv2.CAP_PROP_FRAME_HEIGHT))
                            else:  # stream
                                fps, w, h = 30, im0.shape[1], im0.shape[0]
                            save_path = str(Path(save_path).with_suffix('.mp4'))  # force *.mp4 suffix on results videos
                            vid_writer[i] = cv2.VideoWriter(save_path, cv2.VideoWriter_fourcc(*'mp4v'), fps, (w, h))
                        vid_writer[i].write(im0)
    ​
            # Print time (inference-only)
            LOGGER.info(f"{s}{'' if len(det) else '(no detections), '}{dt[1].dt * 1E3:.1f}ms")
  6. 打印输出信息

    # Print results,打印输出信息
        t = tuple(x.t / seen * 1E3 for x in dt)  # 统计每张图片的平均时间
        LOGGER.info(f'Speed: %.1fms pre-process, %.1fms inference, %.1fms NMS per image at shape {(1, 3, *imgsz)}' % t)
        if save_txt or save_img:
            s = f"\n{len(list(save_dir.glob('labels/*.txt')))} labels saved to {save_dir / 'labels'}" if save_txt else ''
            LOGGER.info(f"Results saved to {colorstr('bold', save_dir)}{s}")
        if update:
            strip_optimizer(weights[0])  # update model (to fix SourceChangeWarning)
     
posted @ 2023-03-15 17:24  CherriesOvO  阅读(1607)  评论(1编辑  收藏  举报