Multi-Output Image Sensor Compression and Decompression
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Solution Overview
Problem
Existing image reading apparatuses using multi-output type image sensors face challenges in processing 1-line image data at high speed with a simple circuit arrangement without holding a line memory, as they require complex circuits to determine interframe and intraframe image data and complicate the compression and decompression processes.
Innovation Solution
An image reading apparatus and method that employs a multi-output type image sensor with a compression unit for different compression methods, a storage unit for compressed data, a decompression unit that changes methods based on pixel count, and a counting unit to manage pixel input, allowing for high-speed processing without a line memory.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a multi-output type image sensor is used to read images at high speed, then reading speed is improved, but circuit complexity increases due to the need for complex determination circuits to handle interframe and intraframe image data
Solution Approach 1:
The patent segments the image data processing by dividing it into interframe image data and intraframe image data based on pixel position. The determination circuit identifies whether each pixel belongs to the first pixel of a sensor chip (interframe) or subsequent pixels (intraframe), allowing different compression methods to be applied to each segment. This segmentation resolves the contradiction by enabling high-speed processing through parallel handling of different data types while keeping the determination circuit relatively simple.
Solution Approach 2:
The patent dynamically changes the decompression method based on the pixel position and type. The determination circuit dynamically identifies interframe versus intraframe image data, and the system dynamically switches between different decompression approaches (DPCM for interframe, simple decompression for intraframe). This dynamic adaptation allows the system to maintain high processing speed while managing circuit complexity through context-dependent processing.
2Quantity of substance
If DPCM encoding method is used to compress image data from 16 bits into 8 bits, then data compression ratio is improved, but processing complexity increases for determining and applying different compression methods
Solution Approach 1:
The patent applies different compression qualities to different parts of the image data based on their position and type. Interframe image data (first pixel of each sensor chip) is processed with simple decompression, while intraframe image data (subsequent pixels) is processed with DPCM decompression. This local quality approach allows the system to achieve good overall compression ratios while simplifying processing for specific data segments, thereby resolving the contradiction between compression efficiency and processing complexity.
Solution Approach 2:
The patent changes the decompression parameter (method type) based on the image data type. The determination circuit changes the processing parameter dynamically: using one decompression method for interframe data and another for intraframe data. This parameter change strategy enables the system to achieve high compression ratios where needed while maintaining simple processing where appropriate, resolving the contradiction between compression ratio and processing complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables high-speed image processing with a simple circuit arrangement by changing decompression methods based on pixel count, reducing the need for a line memory and simplifying the circuitry, thus improving processing efficiency.
Implementation Method 1
photoelectrically converting reflected light from the document by a line image sensor made up of a plurality of elements, and storing charges
Data Source
AI summary
An image reading apparatus has an image sensor in which a plurality of sensor arrays for reading a document image are connected into a line, and parallel-output image data. In the image reading apparatus, of image data output from each sensor array, image data of a pixel at one end and image data of the remaining pixels are compressed by different compression methods. The compressed data of one line are decompressed by a set method at the timing when the number of pixels reaches a preset number of pixels.