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Grad-CAM(may be errors).py
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Grad-CAM(may be errors).py
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def resize_1d(array, shape):
res = np.zeros(shape)
if array.shape[0] >= shape:
ratio = array.shape[0]/shape
for i in range(array.shape[0]):
res[int(i/ratio)] += array[i]*(1-(i/ratio-int(i/ratio)))
if int(i/ratio) != shape-1:
res[int(i/ratio)+1] += array[i]*(i/ratio-int(i/ratio))
else:
res[int(i/ratio)] += array[i]*(i/ratio-int(i/ratio))
res = res[::-1]
array = array[::-1]
for i in range(array.shape[0]):
res[int(i/ratio)] += array[i]*(1-(i/ratio-int(i/ratio)))
if int(i/ratio) != shape-1:
res[int(i/ratio)+1] += array[i]*(i/ratio-int(i/ratio))
else:
res[int(i/ratio)] += array[i]*(i/ratio-int(i/ratio))
res = res[::-1]/(2*ratio)
array = array[::-1]
else:
ratio = shape/array.shape[0]
left = 0
right = 1
for i in range(shape):
if left < int(i/ratio):
left += 1
right += 1
if right > array.shape[0]-1:
res[i] += array[left]
else:
res[i] += array[right] * \
(i - left * ratio)/ratio+array[left]*(right*ratio-i)/ratio
res = res[::-1]
array = array[::-1]
left = 0
right = 1
for i in range(shape):
if left < int(i/ratio):
left += 1
right += 1
if right > array.shape[0]-1:
res[i] += array[left]
else:
res[i] += array[right] * \
(i - left * ratio)/ratio+array[left]*(right*ratio-i)/ratio
res = res[::-1]/2
array = array[::-1]
return res
class ActivationsAndGradients:
""" Class for extracting activations and
registering gradients from targetted intermediate layers """
def __init__(self, model, target_layer):
self.model = model
self.gradients = []
self.activations = []
target_layer.register_forward_hook(self.save_activation)
target_layer.register_backward_hook(self.save_gradient)
def save_activation(self, module, input, output):
self.activations.append(output)
def save_gradient(self, module, grad_input, grad_output):
# Gradients are computed in reverse order
self.gradients = [grad_output[0]] + self.gradients
def __call__(self, x):
self.gradients = []
self.activations = []
return self.model(x)
class BaseCAM:
def __init__(self, model, target_layer, use_cuda=False):
self.model = model.eval()
self.target_layer = target_layer
self.cuda = use_cuda
if self.cuda:
self.model = model.cuda()
self.activations_and_grads = ActivationsAndGradients(self.model, target_layer)
def forward(self, input_img):
return self.model(input_img)
def get_cam_weights(self,
input_tensor,
target_category,
activations,
grads):
raise Exception("Not Implemented")
def get_loss(self, output, target_category):
return output[target_category]
def __call__(self, input_tensor, target_category=None):
if self.cuda:
input_tensor = input_tensor.cuda()
output = self.activations_and_grads(input_tensor)
if target_category is None:
target_category = np.argmax(output.cpu().data.numpy())
self.model.zero_grad()
loss = self.get_loss(output, target_category)
loss.backward(retain_graph=True)
activations = self.activations_and_grads.activations[-1].cpu().data.numpy()[0, :]
grads = self.activations_and_grads.gradients[-1].cpu().data.numpy()[0, :]
#weights = np.mean(grads, axis=(0))
weights = self.get_cam_weights(input_tensor, target_category, activations, grads)
cam = np.zeros(activations.shape[1:], dtype=np.float32)
for i, w in enumerate(weights):
cam += w * activations[i, :]
# cam = activations.dot(weights)
# cam = activations.dot(weights)
# print(input_tensor.shape[1])
cam = resize_1d(cam, (input_tensor.shape[2]))
cam = np.maximum(cam, 0)
heatmap = (cam - np.min(cam)) / (np.max(cam) - np.min(cam) + 1e-10)
return heatmap
class GradCAM(BaseCAM):
def __init__(self, model, target_layer, use_cuda=False):
super(GradCAM, self).__init__(model, target_layer, use_cuda)
def get_cam_weights(self, input_tensor,
target_category,
activations, grads):
return np.mean(grads, axis=1)
model = Net1()
model.load_state_dict(torch.load('./data7/parameternn.pt'))
target_layer = model.p2_6
net = GradCAM(model, target_layer)
from settest import Test
input_tensor = Test.Data[100:101, :]
input_tensor = torch.tensor(input_tensor, dtype=torch.float32)
#plt.figure(figsize=(5, 1))
output = net(input_tensor)