CODEWITHSUNDEEP
pythondeep-learningpytorch
user16230686
user16230686

Reputation:

How to get confidence score from a trained pytorch model

I have a trained PyTorch model and I want to get the confidence score of predictions in range (0-100) or (0-1). The code below is giving me a score but its range is undefined. I want the score in a defined range of (0-1) or (0-100). Any idea how to get this?

conf, classes = torch.max(output, 1)

My code:

model = torch.load(r'best.pt')
model.eval()
def preprocess(imgs):
    im = torch.from_numpy(imgs)
    im = im.float()  # uint8 to fp16/32
    im /= 255.0
    return im

img_path = cv2.imread("/content/634282.jpg",0)
cropped = cv2.resize(img_path,(28,28))
imgs = preprocess(np.array([[cropped]]))
def predict_allCharacters(imgs):
    output = model(imgs)
    conf, classes = torch.max(output, 1)
    class_names = '0123456789'
    return conf, class_names[classes.item()]

Model definition:

class CNN(nn.Module):
    def __init__(self):
        super(CNN, self).__init__()
        self.conv1 = nn.Sequential(         
            nn.Conv2d(
                in_channels=1,              
                out_channels=16,            
                kernel_size=5,              
                stride=1,                   
                padding=2,                  
            ),                              
            nn.ReLU(),                      
            nn.MaxPool2d(kernel_size=2),    
        )
        self.conv2 = nn.Sequential(         
            nn.Conv2d(16, 32, 5, 1, 2),     
            nn.ReLU(),                      
            nn.MaxPool2d(2),                
        )
        # fully connected layer, output 10 classes
        self.out = nn.Linear(32 * 7 * 7, 37)
    def forward(self, x):
        x = self.conv1(x)
        x = self.conv2(x)
        # flatten the output of conv2 to (batch_size, 32 * 7 * 7)
        x = x.view(x.size(0), -1)       
        output = self.out(x)
        return output    # return x for visualization

Upvotes: 1

Views: 7974

Answers (1)

Berriel
Berriel

Reputation: 13601

In your case, output represents the logits. One way of getting a probability out of them is to use the Softmax function. As it seems that output contains the outputs from a batch, not a single sample, you can do something like this:

probs = torch.nn.functional.softmax(output, dim=1)

Then, in probs, each row would have the probability (i.e., in range [0, 1], sum=1) of each class for a given sample.

So, your predict_allCharacters could be modified to:

def predict_allCharacters(imgs):
    output = model(imgs)
    probs = torch.nn.functional.softmax(output, dim=1)
    conf, classes = torch.max(probs, 1)
    class_names = '0123456789'
    return conf, class_names[classes.item()]

Upvotes: 4

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