Improving the Contrast of Pseudothermal Ghost Images Based on the Measured Signal Distribution of Speckle Fields

Abstract

In this study, we examine the quality of microscale ghost images as a function of the measured histographic signal distribution of the speckle fields from a nonuniform pseudothermal light source. This research shows that the distribution of the detected signal level on each pixel of the camera plays a significant role in improving the contrast-to-noise ratio (CNR) of pseudothermal ghost imaging. To our knowledge, the scaling of CNR with different pixel intensity distributions of the speckle fields is observed for the first time in the field of pseudothermal microscale ghost imaging. The experimental observations are in very good agreement with numerical analysis. Based on these findings, we can predict the settings for light sources that will maximize the CNR of microscale ghost images.

Improvements of Computational Ghost Imaging by Using Sequenced Speckle

“…While the TGI demonstrated good CNR, the corresponding resolution was lower (R = 1.10). Overall, our experimental results were consistent with existing theories [18,19], enabling subsequent comparisons with the SGI method.…”

“…Based on the findings from previous pseudo-thermal ghost imaging experiments [19], we have confirmed a significant degradation in the quality of ghost images as the speckle size increases. However, it is observed that with larger speckle sizes, the speed of image appearance during reconstruction also increases.…”

“…To quantitatively evaluate the retrieved ghost image quality, we employ the contrast-to-noise ratio (CNR) and resolution. The CNR is commonly calculated by comparing the object signal strength to the background signal strength and normalizing it to the image noise [18,19]. This measure helps distinguish object signals from background noise.…”

“…By predefining speckle patterns with the modulator, GI can be simplified using only a single beam and a single-pixel detector. Recently, speckle fields have been extensively utilized in the study and application of GI, employing both PGI and CGI approaches [16][17][18][19]. Numerous advanced GI schemes with well-designed patterns have been proposed, including phase-shifting sinusoidal patterns [20], Walsh-Hadamard patterns [21], and Gram-Schmidt-processed orthonormal patterns [22].…”

Image-Enhanced Pseudo-Thermal Ghost Imaging with Hybrid Speckle Pattern

“…Compared to ghost imaging based on entangled photon pairs, PGI is very flexible regarding wavelength, e.g., X-ray ghost imaging has been demonstrated [9][10][11][12]. Thus, in recent years, PGI has been investigated extensively [13][14][15][16][17] to overcome the limitations of image quality.…”