There are programs that automatically hook into the game, captures the text and sends it off for translation. Google for "text hooker" and you will find a lot of options. I used one 15 years ago, so I can't say how well the current ones work.
I was planning of Translating Sakura Wars 2 for the Sega Saturn and a Text Hooker to my knowledge does not work
However i just read that Bluestacks (Android Emulator) can Instant translate the Picture and put overlays on the Japanese text.
I will try to Run Retroarch on Bluestacks and wish me luck that it works