Image Quality Measurement Markers (IQMM) is a plug-in for ImageJ (Fiji) to calculate full-reference quality metrics. The plugin allows you to calculate indicators such as SSIM, SNR [db], CNR [db], PSNR [db], RMSE and MAE.

Plugin works on Macro: run("IQMM", "reference=Image1.png test=Image2.png ssim snr cnr psnr rmse mae");