diff --git a/pytorch_grad_cam/utils/roi.py b/pytorch_grad_cam/utils/roi.py
new file mode 100644
index 00000000..aed8e60a
--- /dev/null
+++ b/pytorch_grad_cam/utils/roi.py
@@ -0,0 +1,157 @@
+import numpy as np
+import torch
+import matplotlib.pyplot as plt
+from skimage import measure
+import collections
+
+def gui_get_point(image, i=None, j=None):
+    fig = plt.figure('Input Pick An Point')
+    scale = np.mean(image.shape[:2])
+    if len(image.shape)==3:
+        pImg = plt.imshow(image)
+    else:
+        pImg = plt.matshow(image)
+
+    pMarker = plt.scatter(j, i, c='r', s=scale, marker='x')
+    ret = plt.ginput(1)
+    if ret == None or ret == []:
+        pass
+    else:
+        j, i = ret[0]
+        j, i= int(j), int(i)
+    pMarker.remove()
+    pMarker = plt.scatter(j, i, c='r', s=scale, marker='x')
+    plt.close(fig)
+    return i, j
+
+class BaseROI:
+    def __init__(self, image = None):
+        self.image = image
+        self.roi = torch.Tensor([1])
+        self.fullroi = None
+        self.i = None
+        self.j = None
+
+    def setROIij(self):
+        print(f'Shape of ROI:{self.roi.shape}')
+        self.i = np.where(self.roi == 1)[0]
+        self.j = np.where(self.roi == 1)[1]
+        print(f'Lengths of i and j index lists: {len(self.i)}, {len(self.j)}')
+
+    def meshgrid(self):
+        ylist = np.linspace(0, self.image.shape[0], self.image.shape[0])
+        xlist = np.linspace(0, self.image.shape[1], self.image.shape[1])
+        return np.meshgrid(xlist, ylist)
+
+    def apply_roi(self, output):
+        return self.roi.to(output.device) * output
+
+
+class PixelROI(BaseROI):
+    def __init__(self, i, j, image):
+        self.image = image
+        self.roi = torch.zeros((image.shape[-3], image.shape[-2]))
+        self.roi[i, j] = 1
+        self.i = i
+        self.j = j
+
+    def pickPixel(self):
+        self.i, self.j = gui_get_point(self.image, self.i, self.j)
+        self.roi.zero_()
+        self.roi[self.i, self.j] = 1
+        print(f'ROI Point: {self.i},{self.j}')
+
+def filter_connected_components(values, counts, exclude):
+    selected_indices=[]
+    selected_counts=[]
+    selected_values=[]
+    for i in range(len(values)):
+        if values[i] != exclude:
+            selected_indices.append([i])
+            selected_values.append(values[i])
+            selected_counts.append(counts[i])
+    return selected_indices, selected_values, selected_counts
+
+class ClassROI(BaseROI):
+    def __init__(self, image, pred, cls, background=0):
+        self.image = image
+        self.pred = pred
+        self.cls = cls
+        self.roi = (pred == cls).reshape(image.shape[-3], image.shape[-2])
+        self.background = background
+        print(f'Valid ROI pixels: {torch.sum(self.roi).numpy()} of class {self.cls}')
+
+    def connectedComponents(self):
+        all_labels = measure.label(self.pred)
+        (values, counts) = np.unique(all_labels, return_counts=True)
+        print("connectedComponents values, counts: ", values, counts)
+        return all_labels, values, counts
+
+    def largestComponent(self):
+        all_labels, values, counts = self.connectedComponents()
+        # find the largest component
+        selected_indices, selected_values, selected_counts = filter_connected_components(values,
+                                                                                         counts,
+                                                                                         self.background)
+        ind = selected_indices[np.argmax(selected_counts)]
+        print("largestComponent argmax: ", ind)
+        self.roi = torch.Tensor(all_labels == ind)
+        print(f'Valid ROI pixels: {torch.sum(self.roi).numpy()} of class {values[ind]}')
+
+    def smallestComponent(self):
+        all_labels, values, counts = self.connectedComponents()
+        selected_indices, selected_values, selected_counts = filter_connected_components(values,
+                                                                                         counts,
+                                                                                         self.background)
+        ind = selected_indices[np.argmin(selected_counts)]
+        print("smallestComponent argmin: ", ind)
+        self.roi = torch.Tensor(all_labels == ind)
+        print(f'Valid ROI pixels: {torch.sum(self.roi).numpy()} of class {values[ind]}')
+
+    def pickClass(self):
+        i, j = gui_get_point(self.pred)
+        self.cls = self.pred[i, j]
+        self.roi = (self.pred == self.cls).reshape(self.image.shape[-3], self.image.shape[-2])
+        print(f'Valid ROI pixels: {torch.sum(self.roi).numpy()} of class {self.cls}')
+
+    def pickComponentClass(self):
+        i, j = gui_get_point(self.pred)
+        all_labels, values, counts = self.connectedComponents()
+        ind = all_labels[i, j]
+        self.cls = all_labels[i, j]
+        self.roi = torch.Tensor(all_labels == ind).reshape(self.image.shape[-3], self.image.shape[-2])
+        print(f'Valid ROI pixels: {torch.sum(self.roi).numpy()} of class {self.cls}')
+
+# Get tensor from output of network. Some segmentation network returns more than 1 tensor.
+def get_output_tensor(output, verbose=False):
+    if isinstance(output, torch.Tensor):
+        return output
+    elif isinstance(output, collections.OrderedDict):
+        k = next(iter(output.keys()))
+        if verbose: print(f'Select "{k}" from dict {output.keys()}')
+        return output[k]
+    elif isinstance(output, list):
+        if verbose: print(f'Select "[0]" from list(n={len(output)})')
+        return output[0]
+    else:
+        raise RuntimeError(f'Unknown type {type(output)}')
+
+class SegModel(torch.nn.Module):
+    def __init__(self, model, roi=None):
+        super(SegModel, self).__init__()
+        self.model = model
+        self.roi = roi
+
+    def forward(self, x):
+        output = self.model(x) # might be multiple tensors
+        output = get_output_tensor(output) # Ensure only one tensor
+
+        N = output.shape[-3]
+        if N == 1: # if the original problem is binary using sigmoid, change to one-hot style.
+            output = torch.log_softmax([-output, output], dim=-3)
+
+        if self.roi is not None:
+            output = self.roi.apply_roi(output)
+        output = torch.sum(output, dim=(-2, -1))
+        return output
+
diff --git a/requirements.txt b/requirements.txt
index 9f05c345..f4d4350e 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,9 +1,11 @@
-dataclasses==0.8
+dataclasses
 dicom-factory==0.0.3
 numpy==1.19.5
 Pillow==8.1.1
 torch==1.7.1
 torchvision==0.8.2
 typing-extensions==3.7.4.3
+scikit-image
 ttach
-tqdm
\ No newline at end of file
+tqdm
+opencv-python
diff --git a/segcam.py b/segcam.py
new file mode 100644
index 00000000..a2a2e916
--- /dev/null
+++ b/segcam.py
@@ -0,0 +1,156 @@
+import argparse
+import cv2
+import numpy as np
+import torch
+import torch.nn
+from torchvision import models
+import matplotlib.pyplot as plt
+
+from pytorch_grad_cam import GradCAM, \
+                             ScoreCAM, \
+                             GradCAMPlusPlus, \
+                             AblationCAM, \
+                             XGradCAM, \
+                             EigenCAM, \
+                             EigenGradCAM
+
+from pytorch_grad_cam.utils.roi import BaseROI, \
+                                    PixelROI, \
+                                    ClassROI, \
+                                    get_output_tensor, \
+                                    SegModel
+
+from pytorch_grad_cam import GuidedBackpropReLUModel
+from pytorch_grad_cam.utils.image import show_cam_on_image, \
+                                         deprocess_image, \
+                                         preprocess_image
+
+
+def get_args():
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--use-cuda', action='store_true', default=False,
+                        help='Use NVIDIA GPU acceleration')
+    parser.add_argument('--image-path', type=str, default='./examples/both.png',
+                        help='Input image path')
+    parser.add_argument('--aug_smooth', action='store_true',
+                        help='Apply test time augmentation to smooth the CAM')
+    parser.add_argument('--eigen_smooth', action='store_true',
+                        help='Reduce noise by taking the first principle componenet'
+                        'of cam_weights*activations')
+    parser.add_argument('--method', type=str, default='gradcam',
+                        choices=['gradcam', 'gradcam++', 'scorecam', 'xgradcam',
+                                 'ablationcam', 'eigencam', 'eigengradcam'],
+                        help='Can be gradcam/gradcam++/scorecam/xgradcam'
+                             '/ablationcam/eigencam/eigengradcam')
+    parser.add_argument('--roimode', type=int, default='0')
+    args = parser.parse_args()
+    args.use_cuda = args.use_cuda and torch.cuda.is_available()
+    if args.use_cuda:
+        print('Using GPU for acceleration')
+    else:
+        print('Using CPU for computation')
+
+    return args
+
+
+if __name__ == '__main__':
+    """ python cam.py -image-path <path_to_image>
+    Example usage of loading an image, and computing:
+        1. CAM
+        2. Guided Back Propagation
+        3. Combining both
+    """
+
+    args = get_args()
+    methods = \
+        {"gradcam": GradCAM,
+         "scorecam": ScoreCAM,
+         "gradcam++": GradCAMPlusPlus,
+         "ablationcam": AblationCAM,
+         "xgradcam": XGradCAM,
+         "eigencam": EigenCAM,
+         "eigengradcam": EigenGradCAM}
+
+    model = models.segmentation.fcn_resnet50(pretrained=True)
+    model.eval()
+    # Choose the target layer you want to compute the visualization for.
+    # Usually this will be the last convolutional layer in the model.
+    # Some common choices can be:
+    # Resnet18 and 50: model.layer4[-1]
+    # VGG, densenet161: model.features[-1]
+    # mnasnet1_0: model.layers[-1]
+    # You can print the model to help chose the layer
+    target_layer = model.backbone.layer4[-1]
+
+    rgb_img = cv2.imread(args.image_path, 1)[:, :, ::-1]
+    rgb_img = np.float32(rgb_img) / 255
+    input_tensor = preprocess_image(rgb_img, mean=[0.485, 0.456, 0.406], 
+                                             std=[0.229, 0.224, 0.225])
+
+    ROIMode = args.roimode
+    if ROIMode == 0:
+        ## All pixels
+        segmodel = SegModel(model, roi=BaseROI(rgb_img))
+    elif ROIMode == 1:
+        ## Single code assigned roi
+        roi = PixelROI(50, 130, rgb_img)
+        segmodel = SegModel(model, roi=roi)
+    elif ROIMode == 2:
+        ## User pick a pixel
+        roi = PixelROI(50, 130, rgb_img)
+        ## Before or after pass to model, both work
+        # roi.pickPoint()
+        segmodel = SegModel(model, roi=roi)
+        roi.pickPixel()
+    elif ROIMode == 3:
+        ## Of specific class (GT or predict, depending on what user passes)
+        pred = torch.argmax(get_output_tensor(model(input_tensor)), -3).squeeze(0)
+        roi = ClassROI(rgb_img, pred, 12)
+        # roi.largestComponent()
+        # roi.smallestComponent()
+        # roi.pickClass()
+        roi.pickComponentClass()
+        segmodel = SegModel(model, roi=roi)
+
+
+    cam = methods[args.method](model=segmodel,
+                               target_layer=target_layer,
+                               use_cuda=args.use_cuda)
+
+    # If None, returns the map for the highest scoring category.
+    # Otherwise, targets the requested category.
+    target_category = None
+
+    # AblationCAM and ScoreCAM have batched implementations.
+    # You can override the internal batch size for faster computation.
+    cam.batch_size = 32
+
+    grayscale_cam = cam(input_tensor=input_tensor,
+                        target_category=target_category,
+                        aug_smooth=args.aug_smooth,
+                        eigen_smooth=args.eigen_smooth)
+
+    # Here grayscale_cam has only one image in the batch
+    grayscale_cam = grayscale_cam[0, :]
+
+    cam_image = show_cam_on_image(rgb_img, grayscale_cam)
+
+    gb_model = GuidedBackpropReLUModel(model=segmodel, use_cuda=args.use_cuda)
+    gb = gb_model(input_tensor, target_category=target_category)
+
+    cam_mask = cv2.merge([grayscale_cam, grayscale_cam, grayscale_cam])
+    cam_gb = deprocess_image(cam_mask * gb)
+    gb = deprocess_image(gb)
+
+    if True:
+        plt.figure()
+        plt.imshow(cam_image)
+        # plt.figure()
+        # plt.imshow(gb)
+        plt.figure()
+        plt.imshow(cam_gb)
+        plt.show()
+    else:
+        cv2.imwrite(f'{args.method}_cam.jpg', cam_image)
+        cv2.imwrite(f'{args.method}_gb.jpg', gb)
+        cv2.imwrite(f'{args.method}_cam_gb.jpg', cam_gb)