Instance Segmentation task

      import torch
import numpy as np
from PIL import Image
import torchvision
import json
import matplotlib.pyplot as plt
import cv2

with open('class_mapping.json') as data:
    mappings = json.load(data)

class_mapping = {item['model_idx']: item['class_name'] for item in mappings}

device = torch.device('cuda' if torch.cuda.is_available() else 'cpu')

model = torch.jit.load('model.pt').to(device)

image_path = '/path/to/your/image'
image = Image.open(image_path)
# Transform your image if the config.yaml shows
# you used any image transforms for validation data
image = np.array(image)
h, w = image.shape[:2]
# Convert to torch tensor
x = torch.from_numpy(image).to(device)
with torch.no_grad():
    # Convert to channels first, convert to float datatype
    x = x.permute(2, 0, 1).float()
    y = model(x)
    # Some optional postprocessing, you can change the 0.5 iou
    # overlap as needed
    to_keep = torchvision.ops.nms(y['pred_boxes'], y['scores'], 0.5)
    y['pred_boxes'] = y['pred_boxes'][to_keep]
    y['pred_classes'] = y['pred_classes'][to_keep]
    y['pred_masks'] = y['pred_masks'][to_keep]

    # Draw you box predictions:
    all_masks = np.zeros((h, w), dtype=np.int8)
    instance_idx = 1
    for mask, bbox, label in zip(reversed(y['pred_masks']),
                                 y['pred_boxes'],
                                 y['pred_classes']):
        bbox = list(map(int, bbox))
        x1, y1, x2, y2 = bbox
        class_idx = label.item()
        class_name = class_mapping[class_idx]
        cv2.rectangle(image, (x1, y1), (x2, y2), (255, 0, 0), 4)
        cv2.putText(
            image,
            class_name,
            (x1, y1),
            cv2.FONT_HERSHEY_SIMPLEX,
            4,
            (255, 0, 0)
        )
        all_masks[mask == 1] = instance_idx
        instance_idx += 1
# Display predicted masks, boxes and classes on your image
plt.imshow(image)
plt.imshow(all_masks, alpha=0.5)
plt.show()
    

      import torch
import numpy as np
from PIL import Image
import torchvision
import json
import matplotlib.pyplot as plt
import cv2


def paste_mask_in_image_old(mask, box, img_h, img_w, threshold):
    """
    Paste a single mask in an image.
    This is a per-box implementation of :func:`paste_masks_in_image`.
    This function has larger quantization error due to incorrect pixel
    modeling and is not used any more.

    Args:
        mask (Tensor): A tensor of shape (Hmask, Wmask) storing the mask of a single
            object instance. Values are in [0, 1].
        box (Tensor): A tensor of shape (4, ) storing the x0, y0, x1, y1 box corners
            of the object instance.
        img_h, img_w (int): Image height and width.
        threshold (float): Mask binarization threshold in [0, 1].

    Returns:
        im_mask (Tensor):
            The resized and binarized object mask pasted into the original
            image plane (a tensor of shape (img_h, img_w)).
    """
    # Conversion from continuous box coordinates to discrete pixel coordinates
    # via truncation (cast to int32). This determines which pixels to paste the
    # mask onto.
    box = box.to(dtype=torch.int32)  # Continuous to discrete coordinate conversion
    # An example (1D) box with continuous coordinates (x0=0.7, x1=4.3) will map to
    # a discrete coordinates (x0=0, x1=4). Note that box is mapped to 5 = x1 - x0 + 1
    # pixels (not x1 - x0 pixels).
    samples_w = box[2] - box[0] + 1  # Number of pixel samples, *not* geometric width
    samples_h = box[3] - box[1] + 1  # Number of pixel samples, *not* geometric height

    # Resample the mask from it's original grid to the new samples_w x samples_h grid
    mask = Image.fromarray(mask.cpu().numpy())
    mask = mask.resize((samples_w, samples_h), resample=Image.BILINEAR)
    mask = np.array(mask, copy=False)

    if threshold >= 0:
        mask = np.array(mask > threshold, dtype=np.uint8)
        mask = torch.from_numpy(mask)
    else:
        # for visualization and debugging, we also
        # allow it to return an unmodified mask
        mask = torch.from_numpy(mask * 255).to(torch.uint8)

    im_mask = torch.zeros((img_h, img_w), dtype=torch.uint8)
    x_0 = max(box[0], 0)
    x_1 = min(box[2] + 1, img_w)
    y_0 = max(box[1], 0)
    y_1 = min(box[3] + 1, img_h)

    im_mask[y_0:y_1, x_0:x_1] = mask[
        (y_0 - box[1]) : (y_1 - box[1]), (x_0 - box[0]) : (x_1 - box[0])
    ]
    return im_mask


with open('path_to_the_mappings') as data:
    mappings = json.load(data)

class_mapping = {item['model_idx']: item['class_name'] for item in mappings}

device = torch.device('cuda' if torch.cuda.is_available() else 'cpu')

model = torch.jit.load("path_to_the_model").to(device)

image_path = "path_to_the_image"
image = Image.open(image_path).convert('RGB')
# Transform your image if the config.yaml shows
# you used any image transforms for validation data
image = np.array(image)
h, w = image.shape[:2]
# Convert to torch tensor
x = torch.from_numpy(image).to(device)
with torch.no_grad():
    # Convert to channels first, convert to float datatype
    x = x.permute(2, 0, 1).float()
    pred_boxes, pred_classes, pred_masks, scores, _ = model(x)
    # Some optional postprocessing, you can change the 0.5 iou
    # overlap as needed
    to_keep = torchvision.ops.nms(pred_boxes, scores, 0.5)
    pred_boxes = pred_boxes[to_keep]
    pred_classes = pred_classes[to_keep]
    pred_masks = pred_masks[to_keep]

    pred_masks_postprocessed = []
    for box, mask in zip(pred_boxes, pred_masks):
        pred_masks_postprocessed.append(paste_mask_in_image_old(mask[0], box, h, w, 0.5))

    # Draw you box predictions:
    all_masks = np.zeros((h, w), dtype=np.int8)
    instance_idx = 1
    for mask, bbox, label in zip(pred_masks_postprocessed,
                                 pred_boxes,
                                 pred_classes):
        bbox = list(map(int, bbox))
        x1, y1, x2, y2 = bbox
        class_idx = label.item()
        class_name = class_mapping[class_idx]
        cv2.rectangle(image, (x1, y1), (x2, y2), (255, 0, 0), 4)
        cv2.putText(
            image,
            class_name,
            (x1, y1),
            cv2.FONT_HERSHEY_SIMPLEX,
            1,
            (255, 0, 0)
        )
        mask = cv2.resize(mask.squeeze().numpy(), dsize=(w, h),
                          interpolation=cv2.INTER_LINEAR)
        all_masks[mask > 0.5] = instance_idx
        instance_idx += 1
# Display predicted masks, boxes and classes on your image
plt.imshow(image)
plt.imshow(all_masks, alpha=0.5)
plt.show()