一、修改model/yolo.py文件中的Detect类中的forward函数如下
logits_ = [] # 修改---1
logits = x[i][..., 5:] # 修改---2
logits_.append(logits.view(bs, -1, self.no - 5)) # 修改---3
return x if self.training else (torch.cat(z, 1), torch.cat(logits_, 1), x) # 修改---4
二、在model文件夹中，添加yolov5_object_detector.py文件：
import numpy as np
import torch
from models.experimental import attempt_load
from utils.general import xywh2xyxy
from utils.datasets import letterbox
import cv2
import time
import torchvision
import torch.nn as nn
from utils.metrics import box_iou
class YOLOV5TorchObjectDetector(nn.Module):
def __init__(self,
model_weight,
device,
img_size,
names=None,
mode='eval',
confidence=0.45,
iou_thresh=0.45,
agnostic_nms=False):
super(YOLOV5TorchObjectDetector, self).__init__()
self.device = device
self.model = None
self.img_size = img_size
self.mode = mode
self.confidence = confidence
self.iou_thresh = iou_thresh
self.agnostic = agnostic_nms
self.model = attempt_load(model_weight, map_location=device, inplace=False, fuse=False)
self.model.requires_grad_(True)
self.model.to(device)
if self.mode == 'train':
self.model.train()
else:
self.model.eval()
# fetch the names
if names is None:
self.names = ['your dataset classname']
else:
self.names = names
# preventing cold start
img = torch.zeros((1, 3, *self.img_size), device=device)
self.model(img)
@staticmethod
def non_max_suppression(prediction, logits, conf_thres=0.3, iou_thres=0.45, classes=None, agnostic=False,
multi_label=False, labels=(), max_det=300):
"""Runs Non-Maximum Suppression (NMS) on inference and logits results
Returns:
list of detections, on (n,6) tensor per image [xyxy, conf, cls] and pruned input logits (n, number-classes)
"""
nc = prediction.shape[2] - 5 # number of classes
xc = prediction[..., 4] > conf_thres # candidates
# Checks
assert 0 <= conf_thres <= 1, f'Invalid Confidence threshold {conf_thres}, valid values are between 0.0 and 1.0'
assert 0 <= iou_thres <= 1, f'Invalid IoU {iou_thres}, valid values are between 0.0 and 1.0'
# Settings
min_wh, max_wh = 2, 4096 # (pixels) minimum and maximum box width and height
max_nms = 30000 # maximum number of boxes into torchvision.ops.nms()
time_limit = 10.0 # seconds to quit after
redundant = True # require redundant detections
multi_label &= nc > 1 # multiple labels per box (adds 0.5ms/img)
merge = False # use merge-NMS
t = time.time()
output = [torch.zeros((0, 6), device=prediction.device)] * prediction.shape[0]
logits_output = [torch.zeros((0, nc), device=logits.device)] * logits.shape[0]
# logits_output = [torch.zeros((0, 80), device=logits.device)] * logits.shape[0]
for xi, (x, log_) in enumerate(zip(prediction, logits)): # image index, image inference
# Apply constraints
# x[((x[..., 2:4] < min_wh) | (x[..., 2:4] > max_wh)).any(1), 4] = 0 # width-height
x = x[xc[xi]] # confidence
log_ = log_[xc[xi]]
# Cat apriori labels if autolabelling
if labels and len(labels[xi]):
l = labels[xi]
v = torch.zeros((len(l), nc + 5), device=x.device)
v[:, :4] = l[:, 1:5] # box
v[:, 4] = 1.0 # conf
v[range(len(l)), l[:, 0].long() + 5] = 1.0 # cls
x = torch.cat((x, v), 0)
# If none remain process next image
if not x.shape[0]:
continue
# Compute conf
x[:, 5:] *= x[:, 4:5] # conf = obj_conf * cls_conf
# Box (center x, center y, width, height) to (x1, y1, x2, y2)
box = xywh2xyxy(x[:, :4])
# Detections matrix nx6 (xyxy, conf, cls)
if multi_label:
i, j = (x[:, 5:] > conf_thres).nonzero(as_tuple=False).T
x = torch.cat((box[i], x[i, j + 5, None], j[:, None].float()), 1)
else: # best class only
conf, j = x[:, 5:].max(1, keepdim=True)
x = torch.cat((box, conf, j.float()), 1)[conf.view(-1) > conf_thres]
log_ = log_[conf.view(-1) > conf_thres]
# Filter by class
if classes is not None:
x = x[(x[:, 5:6] == torch.tensor(classes, device=x.device)).any(1)]
# Check shape
n = x.shape[0] # number of boxes
if not n: # no boxes
continue
elif n > max_nms: # excess boxes
x = x[x[:, 4].argsort(descending=True)[:max_nms]] # sort by confidence
# Batched NMS
c = x[:, 5:6] * (0 if agnostic else max_wh) # classes
boxes, scores = x[:, :4] + c, x[:, 4] # boxes (offset by class), scores
i = torchvision.ops.nms(boxes, scores, iou_thres) # NMS
if i.shape[0] > max_det: # limit detections
i = i[:max_det]
if merge and (1 < n < 3E3): # Merge NMS (boxes merged using weighted mean)
# update boxes as boxes(i,4) = weights(i,n) * boxes(n,4)
iou = box_iou(boxes[i], boxes) > iou_thres # iou matrix
weights = iou * scores[None] # box weights
x[i, :4] = torch.mm(weights, x[:, :4]).float() / weights.sum(1, keepdim=True) # merged boxes
if redundant:
i = i[iou.sum(1) > 1] # require redundancy
output[xi] = x[i]
logits_output[xi] = log_[i]
assert log_[i].shape[0] == x[i].shape[0]
if (time.time() - t) > time_limit:
print(f'WARNING: NMS time limit {time_limit}s exceeded')
break # time limit exceeded
return output, logits_output
@staticmethod
def yolo_resize(img, new_shape=(640, 640), color=(114, 114, 114), auto=True, scaleFill=False, scaleup=True):
return letterbox(img, new_shape=new_shape, color=color, auto=auto, scaleFill=scaleFill, scaleup=scaleup)
def forward(self, img):
prediction, logits, _ = self.model(img, augment=False)
prediction, logits = self.non_max_suppression(prediction, logits, self.confidence, self.iou_thresh,
classes=None,
agnostic=self.agnostic)
self.boxes, self.class_names, self.classes, self.confidences = [[[] for _ in range(img.shape[0])] for _ in
range(4)]
for i, det in enumerate(prediction): # detections per image
if len(det):
for *xyxy, conf, cls in det:
# 返回整数
bbox = [int(b) for b in xyxy]
self.boxes[i].append(bbox)
self.confidences[i].append(round(conf.item(), 2))
cls = int(cls.item())
self.classes[i].append(cls)
if self.names is not None:
self.class_names[i].append(self.names[cls])
else:
self.class_names[i].append(cls)
return [self.boxes, self.classes, self.class_names, self.confidences], logits
def preprocessing(self, img):
if len(img.shape) != 4:
img = np.expand_dims(img, axis=0)
im0 = img.astype(np.uint8)
img = np.array([self.yolo_resize(im, new_shape=self.img_size)[0] for im in im0])
img = img.transpose((0, 3, 1, 2))
img = np.ascontiguousarray(img)
img = torch.from_numpy(img).to(self.device)
img = img / 255.0
return img
三、在model文件夹中，添加gradcam.py文件：
import time
import torch
import torch.nn.functional as F
def find_yolo_layer(model, layer_name):
"""Find yolov5 layer to calculate GradCAM and GradCAM++
Args:
model: yolov5 model.
layer_name (str): the name of layer with its hierarchical information.
Return:
target_layer: found layer
"""
hierarchy = layer_name.split('_')
target_layer = model.model._modules[hierarchy[0]]
for h in hierarchy[1:]:
target_layer = target_layer._modules[h]
return target_layer
class YOLOV5GradCAM:
# 初始化，得到target_layer层
def __init__(self, model, layer_name, img_size=(640, 640)):
self.model = model
self.gradients = dict()
self.activations = dict()
def backward_hook(module, grad_input, grad_output):
self.gradients['value'] = grad_output[0]
return None
def forward_hook(module, input, output):
self.activations['value'] = output
return None
target_layer = find_yolo_layer(self.model, layer_name)
# 获取forward过程中每层的输入和输出，用于对比hook是不是正确记录
target_layer.register_forward_hook(forward_hook)
target_layer.register_full_backward_hook(backward_hook)
device = 'cuda' if next(self.model.model.parameters()).is_cuda else 'cpu'
self.model(torch.zeros(1, 3, *img_size, device=device))
def forward(self, input_img, class_idx=True):
"""
Args:
input_img: input image with shape of (1, 3, H, W)
Return:
mask: saliency map of the same spatial dimension with input
logit: model output
preds: The object predictions
"""
saliency_maps = []
b, c, h, w = input_img.size()
preds, logits = self.model(input_img)
for logit, cls, cls_name in zip(logits[0], preds[1][0], preds[2][0]):
if class_idx:
score = logit[cls]
else:
score = logit.max()
self.model.zero_grad()
tic = time.time()
# 获取梯度
score.backward(retain_graph=True)
print(f"[INFO] {cls_name}, model-backward took: ", round(time.time() - tic, 4), 'seconds')
gradients = self.gradients['value']
activations = self.activations['value']
b, k, u, v = gradients.size()
alpha = gradients.view(b, k, -1).mean(2)
weights = alpha.view(b, k, 1, 1)
saliency_map = (weights * activations).sum(1, keepdim=True)
saliency_map = F.relu(saliency_map)
saliency_map = F.interpolate(saliency_map, size=(h, w), mode='bilinear', align_corners=False)
saliency_map_min, saliency_map_max = saliency_map.min(), saliency_map.max()
saliency_map = (saliency_map - saliency_map_min).div(saliency_map_max - saliency_map_min).data
saliency_maps.append(saliency_map)
return saliency_maps, logits, preds
def __call__(self, input_img):
return self.forward(input_img)
class YOLOV5GradCAMPP(YOLOV5GradCAM):
def __init__(self, model, layer_name, img_size=(640, 640)):
super(YOLOV5GradCAMPP, self).__init__(model, layer_name, img_size)
def forward(self, input_img, class_idx=True):
saliency_maps = []
b, c, h, w = input_img.size()
tic = time.time()
preds, logits = self.model(input_img)
print("[INFO] model-forward took: ", round(time.time() - tic, 4), 'seconds')
for logit, cls, cls_name in zip(logits[0], preds[1][0], preds[2][0]):
if class_idx:
score = logit[cls]
else:
score = logit.max()
self.model.zero_grad()
tic = time.time()
# 获取梯度
score.backward(retain_graph=True)
print(f"[INFO] {cls_name}, model-backward took: ", round(time.time() - tic, 4), 'seconds')
gradients = self.gradients['value'] # dS/dA
activations = self.activations['value'] # A
b, k, u, v = gradients.size()
alpha_num = gradients.pow(2)
alpha_denom = gradients.pow(2).mul(2) + \
activations.mul(gradients.pow(3)).view(b, k, u * v).sum(-1, keepdim=True).view(b, k, 1, 1)
# torch.where(condition, x, y) condition是条件，满足条件就返回x，不满足就返回y
alpha_denom = torch.where(alpha_denom != 0.0, alpha_denom, torch.ones_like(alpha_denom))
alpha = alpha_num.div(alpha_denom + 1e-7)
positive_gradients = F.relu(score.exp() * gradients) # ReLU(dY/dA) == ReLU(exp(S)*dS/dA))
weights = (alpha * positive_gradients).view(b, k, u * v).sum(-1).view(b, k, 1, 1)
saliency_map = (weights * activations).sum(1, keepdim=True)
saliency_map = F.relu(saliency_map)
saliency_map = F.interpolate(saliency_map, size=(h, w), mode='bilinear', align_corners=False)
saliency_map_min, saliency_map_max = saliency_map.min(), saliency_map.max()
saliency_map = (saliency_map - saliency_map_min).div(saliency_map_max - saliency_map_min).data
saliency_maps.append(saliency_map)
return saliency_maps, logits, preds
四、在根目录下新建main_gradcam.py文件 :
import os
import random
import time
import argparse
import numpy as np
from models.gradcam import YOLOV5GradCAM, YOLOV5GradCAMPP
from models.yolov5_object_detector import YOLOV5TorchObjectDetector
import cv2
# 数据集类别名
names = ['person', 'bicycle', 'car', 'motorcycle', 'airplane', 'bus', 'train', 'truck', 'boat', 'traffic light',
'fire hydrant', 'stop sign', 'parking meter', 'bench', 'bird', 'cat', 'dog', 'horse', 'sheep', 'cow',
'elephant', 'bear', 'zebra', 'giraffe', 'backpack', 'umbrella', 'handbag', 'tie', 'suitcase', 'frisbee',
'skis', 'snowboard', 'sports ball', 'kite', 'baseball bat', 'baseball glove', 'skateboard', 'surfboard',
'tennis racket', 'bottle', 'wine glass', 'cup', 'fork', 'knife', 'spoon', 'bowl', 'banana', 'apple',
'sandwich', 'orange', 'broccoli', 'carrot', 'hot dog', 'pizza', 'donut', 'cake', 'chair', 'couch',
'potted plant', 'bed', 'dining table', 'toilet', 'tv', 'laptop', 'mouse', 'remote', 'keyboard', 'cell phone',
'microwave', 'oven', 'toaster', 'sink', 'refrigerator', 'book', 'clock', 'vase', 'scissors', 'teddy bear',
'hair drier', 'toothbrush'] # class names
# yolov5s网络中的三个detect层
target_layers = ['model_17_cv3_act', 'model_20_cv3_act', 'model_23_cv3_act']
# Arguments
parser = argparse.ArgumentParser()
parser.add_argument('--model-path', type=str, default="weights/yolov5s.pt", help='Path to the model')
parser.add_argument('--img-path', type=str, default='data/images', help='input image path')
parser.add_argument('--output-dir', type=str, default='outputs/', help='output dir')
parser.add_argument('--img-size', type=int, default=640, help="input image size")
parser.add_argument('--target-layer', type=str, default='model_17_cv3_act',
help='The layer hierarchical address to which gradcam will applied,'
' the names should be separated by underline')
parser.add_argument('--method', type=str, default='gradcam', help='gradcam method')
parser.add_argument('--device', type=str, default='cpu', help='cuda or cpu')
parser.add_argument('--no_text_box', action='store_true',
help='do not show label and box on the heatmap')
args = parser.parse_args()
def get_res_img(bbox, mask, res_img):
mask = mask.squeeze(0).mul(255).add_(0.5).clamp_(0, 255).permute(1, 2, 0).detach().cpu().numpy().astype(
np.uint8)
heatmap = cv2.applyColorMap(mask, cv2.COLORMAP_JET)
# n_heatmat = (Box.fill_outer_box(heatmap, bbox) / 255).astype(np.float32)
n_heatmat = (heatmap / 255).astype(np.float32)
res_img = res_img / 255
res_img = cv2.add(res_img, n_heatmat)
res_img = (res_img / res_img.max())
return res_img, n_heatmat
def plot_one_box(x, img, color=None, label=None, line_thickness=3):
# this is a bug in cv2. It does not put box on a converted image from torch unless it's buffered and read again!
cv2.imwrite('temp.jpg', (img * 255).astype(np.uint8))
img = cv2.imread('temp.jpg')
# Plots one bounding box on image img
tl = line_thickness or round(0.002 * (img.shape[0] + img.shape[1]) / 2) + 1 # line/font thickness
color = color or [random.randint(0, 255) for _ in range(3)]
c1, c2 = (int(x[0]), int(x[1])), (int(x[2]), int(x[3]))
cv2.rectangle(img, c1, c2, color, thickness=tl, lineType=cv2.LINE_AA)
if label:
tf = max(tl - 1, 1) # font thickness
t_size = cv2.getTextSize(label, 0, fontScale=tl / 3, thickness=tf)[0]
outside = c1[1] - t_size[1] - 3 >= 0 # label fits outside box up
c2 = c1[0] + t_size[0], c1[1] - t_size[1] - 3 if outside else c1[1] + t_size[1] + 3
outsize_right = c2[0] - img.shape[:2][1] > 0 # label fits outside box right
c1 = c1[0] - (c2[0] - img.shape[:2][1]) if outsize_right else c1[0], c1[1]
c2 = c2[0] - (c2[0] - img.shape[:2][1]) if outsize_right else c2[0], c2[1]
cv2.rectangle(img, c1, c2, color, -1, cv2.LINE_AA) # filled
cv2.putText(img, label, (c1[0], c1[1] - 2 if outside else c2[1] - 2), 0, tl / 3, [225, 255, 255], thickness=tf,
lineType=cv2.LINE_AA)
return img
# 检测单个图片
def main(img_path):
colors = [[random.randint(0, 255) for _ in range(3)] for _ in names]
device = args.device
input_size = (args.img_size, args.img_size)
# 读入图片
img = cv2.imread(img_path) # 读取图像格式：BGR
print('[INFO] Loading the model')
# 实例化YOLOv5模型，得到检测结果
model = YOLOV5TorchObjectDetector(args.model_path, device, img_size=input_size, names=names)
# img[..., ::-1]: BGR --> RGB
# (480, 640, 3) --> (1, 3, 480, 640)
torch_img = model.preprocessing(img[..., ::-1])
tic = time.time()
# 遍历三层检测层
for target_layer in target_layers:
# 获取grad-cam方法
if args.method == 'gradcam':
saliency_method = YOLOV5GradCAM(model=model, layer_name=target_layer, img_size=input_size)
elif args.method == 'gradcampp':
saliency_method = YOLOV5GradCAMPP(model=model, layer_name=target_layer, img_size=input_size)
masks, logits, [boxes, _, class_names, conf] = saliency_method(torch_img) # 得到预测结果
result = torch_img.squeeze(0).mul(255).add_(0.5).clamp_(0, 255).permute(1, 2, 0).detach().cpu().numpy()
result = result[..., ::-1] # convert to bgr
# 保存设置
imgae_name = os.path.basename(img_path) # 获取图片名
save_path = f'{args.output_dir}{imgae_name[:-4]}/{args.method}'
if not os.path.exists(save_path):
os.makedirs(save_path)
print(f'[INFO] Saving the final image at {save_path}')
# 遍历每张图片中的每个目标
for i, mask in enumerate(masks):
# 遍历图片中的每个目标
res_img = result.copy()
# 获取目标的位置和类别信息
bbox, cls_name = boxes[0][i], class_names[0][i]
label = f'{cls_name} {conf[0][i]}' # 类别+置信分数
# 获取目标的热力图
res_img, heat_map = get_res_img(bbox, mask, res_img)
res_img = plot_one_box(bbox, res_img, label=label, color=colors[int(names.index(cls_name))],
line_thickness=3)
# 缩放到原图片大小
res_img = cv2.resize(res_img, dsize=(img.shape[:-1][::-1]))
output_path = f'{save_path}/{target_layer[6:8]}_{i}.jpg'
cv2.imwrite(output_path, res_img)
print(f'{target_layer[6:8]}_{i}.jpg done!!')
print(f'Total time : {round(time.time() - tic, 4)} s')
if __name__ == '__main__':
# 图片路径为文件夹
if os.path.isdir(args.img_path):
img_list = os.listdir(args.img_path)
print(img_list)
for item in img_list:
# 依次获取文件夹中的图片名，组合成图片的路径
main(os.path.join(args.img_path, item))
# 单个图片
else:
main(args.img_path)
五、使用介绍
1、更改main_gradcam.py文件中的类别
2、更改model-path和img-path路径
3、运行main_gradcam.py文件，结果如下
文章来源地址https://www.toymoban.com/news/detail-522129.html
4、如果不想要显示坐标框，可以将main_gradcam.py文件中的下面这段代码注释掉
Appendix
如果以上报错，即为torch版本不对，升级为1.8.0以上就可
也可以将gradcam.py文件中的register_full_backward_hook换成register_backward_hook
reference
【YOLOv5】结合GradCAM热力图可视化_嗜睡的篠龙的博客-CSDN博客_yolov5 热力图https://blog.csdn.net/weixin_43799388/article/details/126207632?spm=1001.2014.3001.5502文章来源：https://www.toymoban.com/news/detail-522129.html
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