Table 1.
Overview of preprocessing techniques and dataset balancing after mask application
| Method | Formula | Description | Parameters |
|---|---|---|---|
| Brightness Adjustment |
|
Adjusts brightness and contrast to enhance feature visibility. | α = 1.5, β = 15 |
| Noise Removal [11] |
|
Reduces salt-and-pepper noise while preserving edges using a median blur filter. | Kernel size k = 3 |
| Contrast Enhancement [12] |
|
Enhances local contrast using CLAHE, avoiding excessive noise amplification. | clipLimit = 2.0, tileGridSize = 3 × 3 |
| Normalization |
|
Scales pixel intensities to the range [0, 1] for faster neural network convergence. | None |
| Applying Mask |
|
Binary mask M extracts regions of interest defined by bounding box annotations | None |
| Resizing |
|
Resizes images to a uniform dimension to ensure consistency in input size for the models. | Final size = 224 × 224, nearest-neighbor interpolation |
| Random Downsampling (Balancing) | - | Randomly reduces the number of samples in each class to match the smallest class size after masking. | Based on class with minimum samples (894) |





