Canon Kabushiki Kaisha

Tatsuo Okano

Katsutoshi Hisada

Yukio Murata

Shigeki Sakurai

Nobuaki Kokubu

Nobuaki Kokuba

An image data processing apparatus capable of high-speed encoding even for intermittently supplied image data is provided with a memory storing image data, an encoder for encoding the image data and/or a decoder for decoding such encoded information and a transfer unit for DMA transfer of the image data from the memory to the encoder. A supply may be provided for supplying the encoder with the reference signals in synchronization with the DMA transfer of the image data by the transfer unit. The encoding and/or decoding are performed intermittently, e.g., in response to supply of the reference signals.

Image data processing apparatus capable of high-speed data encoding

An image signal coding apparatus includes reference and coding line change point detection circuits, reference line shift registers, a coding line shift register, a symbol detection circuit, coding and reference line ROM tables, and a code determination circuit. The coding line change point detection circuit receives a serial reference line image signal in synchronism with a serial coding line image signal. The reference line shift registers receive serial change point data in the reference line image signal and output parallel reference line change point data. The coding line shift register receives serial change point data in the coding line image signal and outputs parallel coding line change point data. The symbol detection circuit monitors output states of the reference and coding line shift registers. A run length counter counts the number of pixels between the change points in the coding line image signal. The ROM tables cooperate with the code determination circuit to code the coding line image signal in response to outputs from the symbol detection circuit and the run length counter.

Image signal coding apparatus

A decoder for two-dimensionally encoded image codes such as modified READ or modified READ codes ensures fast decoding operation by outputting reference codes in parallel while serially discriminating input codes and monitoring the relationship of both codes.

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Yokohama, Japan

Tatsuo Okano