# Image receptor homogeneity

### Deviation in mean pixel value

$MPVRatio_i= \frac{\mu_i}{\mu_I}$

where:

• $\mu_i$: mean pixel value of the i-th ROI
• $\mu_I$: mean pixel value of the whole image

### Deviation in Signal-to-Noise-Ratio (SNR)

$SNRRatio_i= \frac{SNR_i}{SNR_I}= \frac{\frac{\mu_i}{\sigma_i}}{\frac{\mu_I}{\sigma_I}}$

where:

• $\mu_i$: mean pixel value of the i-th ROI
• $\sigma_i$: standard deviation of mean pixel values of the i-th ROI
• $\mu_I$: mean pixel value of the whole image
• $\sigma_I$: standard deviation of mean pixel values of the whole image