Intensity_based_Segmentation (TheAlgorithms#12491)

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* Update intensity-based_segmentation.py

* Update and rename intensity-based_segmentation.py to intensity_based_segmentation.py

* Update intensity_based_segmentation.py

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Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Christian Clauss <cclauss@me.com>

Author: 3 people

computer_vision/intensity_based_segmentation.py

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+# Source: "https://www.ijcse.com/docs/IJCSE11-02-03-117.pdf"
+
+# Importing necessary libraries
+import matplotlib.pyplot as plt
+import numpy as np
+from PIL import Image
+
+
+def segment_image(image: np.ndarray, thresholds: list[int]) -> np.ndarray:
+    """
+    Performs image segmentation based on intensity thresholds.
+
+    Args:
+        image: Input grayscale image as a 2D array.
+        thresholds: Intensity thresholds to define segments.
+
+    Returns:
+        A labeled 2D array where each region corresponds to a threshold range.
+
+    Example:
+        >>> img = np.array([[80, 120, 180], [40, 90, 150], [20, 60, 100]])
+        >>> segment_image(img, [50, 100, 150])
+        array([[1, 2, 3],
+               [0, 1, 2],
+               [0, 1, 1]], dtype=int32)
+    """
+    # Initialize segmented array with zeros
+    segmented = np.zeros_like(image, dtype=np.int32)
+
+    # Assign labels based on thresholds
+    for i, threshold in enumerate(thresholds):
+        segmented[image > threshold] = i + 1
+
+    return segmented
+
+
+if __name__ == "__main__":
+    # Load the image
+    image_path = "path_to_image"  # Replace with your image path
+    original_image = Image.open(image_path).convert("L")
+    image_array = np.array(original_image)
+
+    # Define thresholds
+    thresholds = [50, 100, 150, 200]
+
+    # Perform segmentation
+    segmented_image = segment_image(image_array, thresholds)
+
+    # Display the results
+    plt.figure(figsize=(10, 5))
+
+    plt.subplot(1, 2, 1)
+    plt.title("Original Image")
+    plt.imshow(image_array, cmap="gray")
+    plt.axis("off")
+
+    plt.subplot(1, 2, 2)
+    plt.title("Segmented Image")
+    plt.imshow(segmented_image, cmap="tab20")
+    plt.axis("off")
+
+    plt.show()