USD incorrectly detected

[clemenshelm]

On some bills USD gets incorrectly recognized as currency. In many cases this might be an OCR issue. Maybe it's possible to identify OCR errors and return nil as a currency in these cases.

Bills:

• 2wWmeDavmgjhJ6i2q.pdf
• iEMvjXjJnSRamnZ8L.jpg
• RyBtX66Qf2wghpfeK.pdf
• tH9KgSiMC3BdLe9SR.pdf
• ZqQo7Q3cC5p9dW543.pdf
• HE9a3LbqEuArHW586.pdf

[Tr4in]

On all marked bills the recognizer behaves corretly(Returns nil or the CORRECT currency). On bill iEMvjXjJnSRamnZ8L.jpg it detects £ inside a word that is not a number. It is an OCR error! Correct currency on bill: CHF