Improving Robustness and Visibility of Adversarial CAPTCHA Using Low-Frequency Perturbation.
Takamichi TeradaVo Ngoc Khoi NguyenMasakatsu NishigakiTetsushi OhkiPublished in: AINA (2) (2022)
Keyphrases
- low frequency
- high frequency
- frequency domain
- wavelet transform
- subband
- discrete wavelet transform
- wavelet analysis
- low pass
- low and high frequency
- high resolution
- high frequency components
- dct domain
- wavelet coefficients
- multiresolution
- contourlet transform
- frequency band
- electromagnetic fields
- dct coefficients
- subband decomposition
- fusion rules
- image segmentation