Method for Selecting the Down-Sampling Factor of Photoacoustic Image by Using Cumulative Power Difference in Frequency Domain

As a novel non-invasive imaging technology, a constraint of photoacoustic microscopy (PAM) is its imaging speed. Often, PAM utilizes sparse spatial sampling, which necessitates extensive prior experimentation to accurately select the down-sampling factors. To overcome this limitation, this study proposes a frequency-domain evaluation index, cumulative power difference (CPD), for rapid selection of the optimal down-sampling factor. We apply the proposed CPD to photoacoustic images of the ear and brain of the mouse. The result shows that as the down-sampling factor increases, there is a similar decreasing trend in the quality of the 20 images. CPD was significantly correlated with PCC/MSE/SSIM (p < 0.001). The findings suggest that CPD, with its ability to evaluate the quality of photoacoustic images and quickly quantify the quality loss of down-sampled images without prior inspection. This study contributes to expanding the application range of PAM and supporting its clinical prospects.