CFA (Colour Filter Array)
Definition
The mosaic of colour filters placed over a sensor so that each photosite captures one colour channel. The Bayer pattern (RGGB arrangement) is the most common.
- Full form
- Colour Filter Array
- Function
- Assigns one colour channel per photosite
- Most common pattern
- Bayer RGGB
- Reconstruction step
- Demosaicing
- Forensic relevance
- Basis for CFA inconsistency detection
Common questions
Why does the CFA pattern matter for detecting image tampering?+
The demosaicing process that reconstructs full colour from the CFA leaves a periodic statistical trace across a genuine, untouched image. Splicing or resampling a region disrupts that periodicity, which forensic analysis can detect even when the tampering is invisible to the eye.
Do all cameras use the same CFA pattern?+
No, while Bayer RGGB is the most common consumer pattern, some cameras use different arrangements such as CYGM or X-Trans, so an analyst must know or determine the expected pattern for a given camera model before testing for inconsistency.
Related terms
- Camera Noise Model
- A mathematical description of a sensor's noise as a function of signal level, combining signal-dependent shot noise and signal-independent readout noise. The...
- CFA Phase
- The spatial offset of the CFA mosaic pattern in an image. Pasting a region from a different image or after a non-CFA-aligned...
- Demosaicing
- The algorithm used to interpolate full-colour pixel values from the single-channel raw sensor data. Common methods include bilinear interpolation, gradient-based algorithms (AHD,...
- Noise Residual
- The signal remaining after a denoising filter removes the scene component from an image. For PRNU estimation, the residual approximates the sum...
- Steganography
- Concealing one file inside another in a way that hides the existence of the hidden file. LSB image manipulation, JPEG DCT coefficient...