Method and device for decoding normal form Hoffman hardware in JPEG (Joint Photographic Expert Group) image

The invention discloses a method and a device for decoding normal form Hoffman hardware in a JPEG (Joint Photographic Expert Group) image. The device comprises a shift register, a comparator, a read signal generating module, an address generating module and a codon type and frame finish signal generating module, wherein the shift register is used for temporarily storing the current decoding bit stream; the comparator compares the last one codon of the current length with the value of the shift register to determine whether a normal form Hoffman codon is found or not; the read signal generating module generates an enable signal; the address generating module generates the address of an ROM (Read Only Memory); and the codon type and frame finish signal generating module generates the type of the currently decoded normal form Hoffman codon and the frame finish signal of the current decoding. The method decodes one codon in a shorter clock period by utilizing a shift register mode, can realize the rapid normal form Hoffman codon decoding and has the advantages of high efficiency, few logic resource occupation and the like; and the control logics among all the modules are simple, can reach the higher clock frequency, are especially suitable for the application occasions of high-definition and super-resolution televisions, have simple interfaces with a forestage logic and a backward stage logic, are easy to expand and can be conveniently realized in an ASIC (Application Specific Integrated Circuit) and an FPGA (Field Programmable Gate Array).