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. 2026 Feb 7;26:472. doi: 10.1186/s12903-026-07727-7

Table 1.

Overview of preprocessing techniques and dataset balancing after mask application

Method Formula Description Parameters
Brightness Adjustment Inline graphic Adjusts brightness and contrast to enhance feature visibility. α = 1.5, β = 15
Noise Removal [11] Inline graphic Reduces salt-and-pepper noise while preserving edges using a median blur filter. Kernel size k = 3
Contrast Enhancement [12] Inline graphic Enhances local contrast using CLAHE, avoiding excessive noise amplification. clipLimit = 2.0, tileGridSize = 3 × 3
Normalization Inline graphic Scales pixel intensities to the range [0, 1] for faster neural network convergence. None
Applying Mask Inline graphic Binary mask M extracts regions of interest defined by bounding box annotations None
Resizing Inline graphic 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)