# Name

ccc - calculate cross-correlation coefficient between two images

# Usage

output = ccc(image1, image2 ,[mask])

## Input

- image1
- first input image
- image2
- second input image
- mask
an optional mask image. Only pixels in image1 and image2 for which values of corresponding pixels in mask > 0.5 will be included in calculation.

## Output

- output
- the cross-correlation coefficient between images

# Method

- Cross-correlation coefficient is calculated directly in real space as:
``\c\c\c=(1/(nx)(sum_(k=0)^(nx-1)(f(k)-Ave_f)(g(k)-Ave_g)))/(sigma_f sigma_g``

# Reference

Pratt, W. K., 1992. Digital image processing. Wiley, New York.

# Author / Maintainer

Pawel A. Penczek

# Keywords

- category 1
- STATISTICS
- category 2
- SPATIAL

# Files

statistics.py

# Maturity

- stable
- works for most people, has been tested; test cases/examples available.

# Bugs

None. It is perfect.