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pytorchresnettransfer-learning

Reading test images for resnet18


I am trying to read an image file and classify and image. My model is resnet18 I trained it previously and planning to use a different .py script to classify a list of images. This is my network:

PATH = './net.pth'
model_ft = models.resnet18(pretrained=True)
num_ftrs = model_ft.fc.in_features
model_ft.fc = nn.Linear(num_ftrs, 16)
model_ft.load_state_dict(torch.load(PATH))
model_ft.eval() 

And I am trying to read Images this way:

imsize = 256
loader = transforms.Compose([transforms.Scale(imsize), transforms.ToTensor()])
def image_loader(image_name):
    #load image, returns cuda tensor
    image = Image.open(image_name)
    image = loader(image).float()
    image = Variable(image, requires_grad=True)
    image = image.unsqueeze(0)
    return image.cuda()  

image = image_loader("dataset/test/9673.png")

model_ft(image)

I am getting this error:

 "Given groups=1, weight of size [64, 3, 7, 7], expected input[1, 4, 676, 256] to have 3 channels, but got 4 channels instead"

I've got recommended to remove the unsqueeze for resnet18, doing that I got the following error:

"Expected 4-dimensional input for 4-dimensional weight [64, 3, 7, 7], but got 3-dimensional input of size [4, 676, 256] instead"

I do not quite understand the problem I am dealing with, how should I read my test set? I'll need to write the class ID-s and the file names into a .txt afterwards.


Solution

  • You are using a PNG image which has 4 channels. your network expects 3 channels. Convert to RGB and you should be fine. In your image_loader simply do:

    image = Image.open(image_name).convert('RGB')