文章摘要
这篇文章是一篇展示如何使用PyTorch进行图像处理和模型推理的代码示例。主要步骤包括加载配置文件、准备图像数据、加载预训练模型、进行推理，并在结果中画出矩形框保存图片。代码中还记录了推理的速度，并使用了预训练的PSENet模型。核心内容是通过PyTorch实现图像处理和模型推理的完整流程。
import torch
import numpy as np
import argparse
import os
import os.path as osp
import sys
import time
import json
from mmcv import Config
import cv2
from torchvision import transforms
from dataset import build_data_loader
from models import build_model
from models.utils import fuse_module
from utils import ResultFormat, AverageMeter
def prepare_image(image, target_size):
“””Do image preprocessing before prediction on any data.
:param image: original image
:param target_size: target image size
:return:
preprocessed image
“””
#assert os.path.exists(img), ‘file is not exists’
#img=cv2.imread(img)
img=cv2.cvtColor(image, cv2.COLOR_BGR2RGB)
# h, w=image.shape[:2]
# scale=long_size / max(h, w)
img=cv2.resize(img, target_size)
# 将图片由(w,h)变为(1,img_channel,h,w)
tensor=transforms.ToTensor()(img)
tensor=tensor.unsqueeze_(0)
tensor=tensor.to(torch.device(“cuda:0″))
return tensor
def report_speed(outputs, speed_meters):
total_time=0
for key in outputs:
if ‘time’ in key:
total_time +=outputs[key]
speed_meters[key].update(outputs[key])
print(‘%s: %.4f’ % (key, speed_meters[key].avg))
speed_meters[‘total_time’].update(total_time)
print(‘FPS: %.1f’ % (1.0 / speed_meters[‘total_time’].avg))
def load_model(cfg):
model=build_model(cfg.model)
model=model.cuda()
model.eval()
checkpoint=”psenet_r50_ic15_1024_finetune/checkpoint_580ep.pth.tar”
if checkpoint is not None:
if os.path.isfile(checkpoint):
print(“Loading model and optimizer from checkpoint ‘{}'”.format(checkpoint))
sys.stdout.flush()
checkpoint=torch.load(checkpoint)
d=dict()
for key, value in checkpoint[‘state_dict’].items():
tmp=key[7:]
d[tmp]=value
model.load_state_dict(d)
else:
print(“No checkpoint found at”)
raise
# fuse conv and bn
model=fuse_module(model)
return model
if __name__==’__main__’:
src_dir=”testimg/”
save_dir=”test_save/”
if not os.path.exists(save_dir):
os.makedirs(save_dir)
cfg=Config.fromfile(“PSENet/config/psenet/psenet_r50_ic15_1024_finetune.py”)
for d in [cfg, cfg.data.test]:
d.update(dict(
report_speed=False
))
if cfg.report_speed:
speed_meters=dict(
backbone_time=AverageMeter(500),
neck_time=AverageMeter(500),
det_head_time=AverageMeter(500),
det_pse_time=AverageMeter(500),
rec_time=AverageMeter(500),
total_time=AverageMeter(500)
)
model=load_model(cfg)
model.eval()
count=0
for img_name in os.listdir(src_dir):
img=cv2.imread(src_dir + img_name)
tensor=prepare_image(img, target_size=(1376, 1024))
data=dict()
img_metas=dict()
data[‘imgs’]=tensor
img_metas[‘org_img_size’]=torch.tensor([[img.shape[0], img.shape[1]]])
img_metas[‘img_size’]=torch.tensor([[1376, 1024]])
data[‘img_metas’]=img_metas
data.update(dict(
cfg=cfg
))
with torch.no_grad():
outputs=model(**data)
if cfg.report_speed:
report_speed(outputs, speed_meters)
for bboxes in outputs[‘bboxes’]:
x1=bboxes[0]
y1=bboxes[1]
x2=bboxes[4]
y2=bboxes[5]
cv2.rectangle(img, (x1, y1), (x2, y2), (0, 0, 255), 3)
count=count + 1
cv2.imwrite(save_dir + img_name, img)
print(“img test:”, count)