utils.py

import torch.nn as nn
import torch.nn.functional as F
import torch 
from torchvision import transforms
import cv2
import numpy as np
from pytorch_grad_cam import GradCAM
from pytorch_grad_cam import GradCAM
from pytorch_grad_cam.utils.image import show_cam_on_image

def apply_normalization(chennels):
      return nn.BatchNorm2d(chennels)
  
class CustomResnet(nn.Module):
    def __init__(self):
        super(CustomResnet, self).__init__()
        # Input Block
        drop = 0.0
        # PrepLayer - Conv 3x3 s1, p1) >> BN >> RELU [64k]
        self.preplayer = nn.Sequential(
            nn.Conv2d(3, 64, (3, 3), padding=1, stride=1, bias=False), # 3
            apply_normalization(64),
            nn.ReLU(),
        )
        # Layer1 -
        # X = Conv 3x3 (s1, p1) >> MaxPool2D >> BN >> RELU [128k]
        self.convlayer1 = nn.Sequential(
            nn.Conv2d(64, 128, (3, 3), padding=1, stride=1, bias=False), # 3
            nn.MaxPool2d(2, 2),
            apply_normalization(128),
            nn.ReLU(),
        )
        # R1 = ResBlock( (Conv-BN-ReLU-Conv-BN-ReLU))(X) [128k]
        self.reslayer1 = nn.Sequential(
            nn.Conv2d(128, 128, (3, 3), padding=1, stride=1, bias=False), # 3
            apply_normalization(128),
            nn.ReLU(),
            nn.Conv2d(128, 128, (3, 3), padding=1, stride=1, bias=False), # 3
            apply_normalization(128),
            nn.ReLU(),
        )
        # Conv 3x3 [256k]
        self.convlayer2 = nn.Sequential(
            nn.Conv2d(128, 256, (3, 3), padding=1, stride=1, bias=False), # 3
            nn.MaxPool2d(2, 2),
            apply_normalization(256),
            nn.ReLU(),
        )
        # X = Conv 3x3 (s1, p1) >> MaxPool2D >> BN >> RELU [512k]
        self.convlayer3 = nn.Sequential(
            nn.Conv2d(256, 512, (3, 3), padding=1, stride=1, bias=False), # 3
            nn.MaxPool2d(2, 2),
            apply_normalization(512),
            nn.ReLU(),
        )
        # R1 = ResBlock( (Conv-BN-ReLU-Conv-BN-ReLU))(X) [128k]
        self.reslayer2 = nn.Sequential(
            nn.Conv2d(512, 512, (3, 3), padding=1, stride=1, bias=False), # 3
            apply_normalization(512),
            nn.ReLU(),
            nn.Conv2d(512, 512, (3, 3), padding=1, stride=1, bias=False), # 3
            apply_normalization(512),
            nn.ReLU(),
        )
        self.maxpool3 = nn.MaxPool2d(4, 2)
        self.linear1 = nn.Linear(512,10)

    def forward(self,x):
        x = self.preplayer(x)
        x1 = self.convlayer1(x)
        x2 = self.reslayer1(x1)
        x = x1+x2
        x = self.convlayer2(x)
        x = self.convlayer3(x)
        x1 = self.reslayer2(x)
        x = x+x1
        x = self.maxpool3(x)
        x = x.view(-1, 512)
        x = self.linear1(x)
        return F.log_softmax(x, dim=-1)
    
# Function to run inference and return top classes
def get_gradcam(model,input_img, opacity):
    targets = None
    inv_normalize = transforms.Normalize(
        mean=[-0.50/0.23, -0.50/0.23, -0.50/0.23],
        std=[1/0.23, 1/0.23, 1/0.23]
    )
    device = torch.device('cuda' if torch.cuda.is_available() else 'cpu')
    transform = transforms.ToTensor()
    input_img = transform(input_img)
    input_img = input_img.to(device)
    input_img = input_img.unsqueeze(0)
    outputs = model(input_img)
    _, prediction = torch.max(outputs, 1)
    target_layers = [model.convlayer3[-2]]
    cam = GradCAM(model=model, target_layers=target_layers, use_cuda=True)
    grayscale_cam = cam(input_tensor=input_img, targets=targets)
    grayscale_cam = grayscale_cam[0, :]
    img = input_img.squeeze(0).to('cpu')
    img = inv_normalize(img)
    rgb_img = np.transpose(img, (1, 2, 0))
    rgb_img = rgb_img.numpy()
    visualization = show_cam_on_image(rgb_img, grayscale_cam, use_rgb=True, image_weight=opacity)
    return visualization


def get_misclassified_images(show_misclassified,num):
    if show_misclassified:
        return cv2.imread(f"missclassified_images_examples/{int(num)}_missclassified.png")
    else:
        return None


def main_inference(num_of_output_classes,classes,model,input_img):
    device = torch.device('cuda' if torch.cuda.is_available() else 'cpu')
    transform = transforms.ToTensor()
    input_img = transform(input_img)
    input_img = input_img.to(device)
    input_img = input_img.unsqueeze(0)
    softmax = torch.nn.Softmax(dim=0)
    outputs = model(input_img)
    out = softmax(outputs.flatten())
    _, prediction = torch.max(outputs, 1)
    confidences = {classes[i]:float(out[i]) for i in range(num_of_output_classes)}
    outputs = model(input_img)
    _, prediction = torch.max(outputs, 1)
    return confidences
# def run_inference(input_img, num_of_output_classes,transparency):
#     transform = transforms.ToTensor()
#     input_img = transform(input_img)
#     input_img = input_img.to(device)
#     input_img = input_img.unsqueeze(0)
#     softmax = torch.nn.Softmax(dim=0)
#     outputs = model(input_img)
#     out = softmax(outputs.flatten())
#     _, prediction = torch.max(outputs, 1)
#     confidences = {classes[i]:float(out[i]) for i in range(num_of_output_classes)}
#     target_layers = [model.convlayer3[-2]]
    
#     cam = GradCAM(model=model, target_layers=target_layers, use_cuda=True)
#     grayscale_cam = cam(input_tensor=input_img, targets=targets)
#     grayscale_cam = grayscale_cam[0, :]
#     img = input_img.squeeze(0).to('cpu')
#     img = inv_normalize(img)
#     rgb_img = np.transpose(img, (1, 2, 0))
#     rgb_img = rgb_img.numpy()
#     visualization = show_cam_on_image(rgb_img, grayscale_cam, use_rgb=True, image_weight=transparency)
#     return confidences, rgb_img, transparency,grayscale_cam