# Efficient copyright protection for three CT images based on quaternion polar harmonic Fourier moments

> Research article (Signal Processing, 2019) · cited 60× · AI/ML

**Wikidata**: [openalex:W2950262130](https://www.wikidata.org/wiki/openalex:W2950262130)  
**Source**: https://4ort.xyz/entity/efficient-copyright-protection-for-three-ct-images-based-on-quaternion-polar-harmonic-fourier-moments