A more systematic method of producing image filters was introduced by Hendrik Bode ( 1930 ) .
A more systematic method of producing image filters was further developed by several other investigators including Piloty ( 1937 - 1939 ) and Wilhelm Cauer ( 1934 - 1937 ) .
A more systematic method of producing image filters was introduced by Hendrik Bode ( 1930 ) , and further developed by several other investigators including Piloty ( 1937 - 1939 ) and Wilhelm Cauer ( 1934 - 1937 ) .