Image encoding device, and image encoding method

Abstract

The present invention provides an image encoding device that can balance encoding at a high compression ratio and restoration of a high-quality image by decoding in a short processing time. Compression mode determination means 3 determines a compression mode to be one of DPCM and PCM based on target pixel data inputted from a terminal 21 and predicted data calculated by a predetermined method. For the DPCM, DPCM compression means 5 compresses a difference value between the target pixel data and the predicted data to DPCM encoded data having a predetermined DPCM code length. For the PCM, PCM compression means 7 compresses the target pixel data to PCM encoded data having a PCM code length determined by PCM code length determination means 9. The PCM code length determination means 9 calculates the PCM code length for each piece of target pixel data such that a total of post-encoding code lengths becomes an allowable value or less in a unit of predetermined pixel group among the plurality of pixels. Tag / code output means 13 outputs the encoded data by adding a tag indicating whether the compression mode is the DPCM or the PCM to the encoded data.

Description

technical field [0001] The present invention relates to an image encoding device, in particular to an image encoding device and an image encoding method which are assembled into an interface of an image memory or a bus to reduce the capacity of the image memory or the bandwidth of the access interface. Background technique [0002] In recent years, with the rapid development of semiconductor technology and the high precision of image data, the amount of image data that should be processed by a device or system is increasing explosively. On the other hand, when performing image processing, it is often necessary to temporarily store intermediate image data during processing. [0003] In an image processing apparatus, image data is generally stored in an internal buffer or an external memory through a memory interface or a bus. However, for example, while processing full high-definition images that are transmitted 60 frames per second and each pixel is 30 bits, intermediate im...

AI Technical Summary

Problems solved by technology

However, for example, when processing 60 full-high-definition images per second and each pixel is 30 bits, the intermediate image data of three frames is also stored in the memory for each frame. In this case, it is necessary to 1920 (pixels) × 1080 (pixels) × 60 (pictures) × 30 (pixels) × 3 (screen) × 2 (number of times (reading and writing)) = about 22.4 Gbit / s data transmission capacity, and 1920 (pixels) × 1080 (pixels) × 30 (bits) × 3 (picture) = memory capacity of about 186Mbits, which makes it increasingly difficult to implement with existing circuits

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