# Negative exponential behavior of image mutual information for pseudo-thermal light ghost imaging: Observation, modeling, and verification

## TL;DR

This paper investigates the negative exponential pattern of image mutual information in pseudo-thermal light ghost imaging, develops a semi-quantitative model based on information theory, and experimentally verifies the model's accuracy.

## Contribution

It introduces a novel semi-quantitative model explaining the negative exponential behavior of mutual information in ghost imaging, grounded in the Gaussian nature of detector output distributions.

## Key findings

- Mutual information follows a negative exponential trend with measurement number.
- The Gaussian distribution of detector outputs causes this exponential behavior.
- Experimental results confirm the proposed model's validity.

## Abstract

When use the image mutual information to assess the quality of reconstructed image in pseudo-thermal light ghost imaging, a negative exponential behavior with respect to the measurement number is observed. Based on information theory and a few simple and verifiable assumptions, semi-quantitative model of image mutual information under varying measurement numbers is established. It is the Gaussian characteristics of the bucket detector output probability distribution that leads to this negative exponential behavior. Designed experiments verify the model.