The ITA Advantage: A Fairer Way to See Skin

When building an AI to help detect skin cancer, the most critical challenge isn't just training it to be accurate—it's training it to be fair. Many commercial AI systems perform poorly on darker skin tones because their training data is not balanced, and their algorithms lack an understanding of skin tone variation. This is where the Individual Typology Angle (ITA) comes in .

What is the ITA?

The ITA is a continuous, physics-based measure of skin pigmentation . It's far more precise than the commonly used Fitzpatrick Skin Type (FST) scale, which divides skin into only six discrete categories. Relying on FST can be problematic, as it might group two people with significantly different skin tones into the same "Type IV" category, masking important differences.

By converting an image into the CIELAB color space (a model designed to approximate human vision), the ITA formula uses the L* (lightness) and b* (blue-yellow) channels to calculate a single value. Higher ITA values correspond to lighter skin, while lower values indicate darker skin .

Why is ITA Superior for Fairness?

The primary advantage of ITA is its continuous and objective nature. It helps reduce bias in AI systems by allowing for dynamic calibration—adjusting how the AI processes an image based on the specific skin tone it detects .

• Goes Beyond Simplistic Categories: By replacing a handful of broad boxes with a continuous scale, the ITA allows for more precise fairness adjustments .

• Enables Adaptive Preprocessing: In NOMA AI, when the ITA calculation indicates a higher risk of bias (e.g., for darker skin tones), the system automatically applies adaptive contrast enhancement (CLAHE). This ensures the AI receives a high-quality image optimized for accurate analysis .

• Improves Trust and Transparency: NOMA AI displays the user's ITA score and bias risk level, making the system’s decision-making process more transparent. Users can see if their skin tone falls into a category where the AI might be less reliable, allowing them to make informed decisions about seeking clinical confirmation .

  
  

The Bigger Picture

By using the ITA, NOMA AI addresses a critical limitation in many commercial systems. It demonstrates that diagnostic tools can be both powerful and fair, creating a pathway for AI that serves everyone equally, not just those who are overrepresented in training data.

Research has shown that methods leveraging ITA for skin tone normalization can improve fairness in skin lesion detection without significantly sacrificing accuracy, making them ideal for deployment in low-resource clinical settings .