Image Encoding Apparatus Dynamic Coding Mode Selection
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Solution Overview
Problem
Conventional image encoding methods for binary and text images with boundary portions suffer from reduced image quality and inefficient compression, particularly when using fixed compression ratios, leading to suboptimal bit assignment and encoding efficiency.
Innovation Solution
An image encoding and decoding apparatus/method that dynamically selects between transform coding and pulse code modulation (PCM) based on image characteristics, specifically using PCM for binary and text images to generate a bitstream, and includes a selector to output the appropriate bitstream, ensuring optimal coding for image quality and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If transform coding is used for binary images and text images with boundary portions, then general encoding efficiency is improved, but image quality deteriorates significantly
Solution Approach 1:
The patent implements dynamic mode selection between transform coding and PCM coding based on image type detection. The encoder dynamically switches coding methods: using PCM coding for binary images and text images with boundaries to preserve quality, and transform coding for other image types to maximize compression efficiency. This dynamic adaptation resolves the contradiction by selecting the optimal coding method for each specific image characteristic.
2Device complexity
If fixed compression ratio is used, then encoding complexity is reduced, but bit assignment becomes insufficient for lower portions of frames reducing both image quality and encoding efficiency
Solution Approach 1:
The patent changes the compression ratio parameter dynamically based on image type detection. When binary images or text images with boundaries are detected, the system adjusts the compression ratio to prioritize quality preservation. This parameter adaptation allows the encoder to optimize both quality and efficiency for different image characteristics without requiring complex frame-based bit allocation schemes.
Data Source
AI summary
An image encoding apparatus and method, and an image decoding apparatus and method. An image encoding apparatus includes: an image input unit receiving an image to be encoded; a transform encoding unit transform coding the image provided from the image input unit to generate a first bitstream; a pulse code modulation (PCM) encoding unit PCM coding the image provided from the image input unit to generate a second bitstream; and a selector selecting and outputting one of the first bitstream and the second bitstream depending on characteristics of the image.