Who owns the copyrights to Philipp Franz Von Siebold's lithographs which are found in his works "Nippon" and "Voyage Au Japon - Execute Pendant Les Annees 1823 a 1830"???????

I'm mostly interested in the copyrights to Voyage Au Japon's lithographs. The book was published in 1838 and only a handful of copies are in existance today. The publisher was Arthus Bertrand.