The first time he set foot in this mountainous city in 1987, a bowl of spicy noodles for breakfast, the subtropical greenery and blooms, the historical buildings on the campus of Chongqing University, as well as the vertical landscape of buildings on steep hillsides, all tempted him to plunge into taking up long-term residence in China.

However, the city of soft mist, the rattle of mahjong tiles, hotpot, and friendly residents didn't help him with his challenge of learning Mandarin, especially as he was surrounded by people speaking in dialect all the time, which to him sounded like a different language.

At a time when not so many Chinese could speak foreign languages, Mueller had to study Chinese very hard after work in order to prevent his students at the university from taking a nap in class because they couldn't understand him.

Mueller's projects in Chongqing and later in Shanghai in the 1990s included an AI-based handwritten character recognition system for the fourth national census in 1990 and a license plate recognition system to grant vehicles automatic access to parking lots.

There are tens of thousands of Chinese characters, among which thousands are commonly used. Compared to Latin characters, the thin strokes of Chinese characters required scanners of higher resolution; and because some characters look very similar and are difficult to identify at first glance, even for humans, Mueller and his colleagues developed a system to contextualize them to raise accuracy.

He took business trips to different parts of China — some quite rural — to promote the business and teach residents how to use their systems.

Unlike many foreign Chinese learners who find it much more difficult to write the characters, as a result of his projects, Mueller was able to read Chinese more smoothly than he could speak it.