Image Processing Apparatus Reading Mode Switching
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Solution Overview
Problem
In high-speed image reading, it is challenging to temporarily stop and restart the reading process without disturbing the image of the conveyed document, especially when memory preparation for image data transfer is not completed in time.
Innovation Solution
An image processing apparatus that can switch between two reading modes: the first mode starts conveying the next document before completing the image reading of the previous page, and the second mode waits until the previous page is fully read before starting the conveyance of the next document, ensuring timely preparation for image data transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-speed image reading is performed at 30 to 100 pages per minute, then productivity is improved, but the ability to temporarily stop and restart reading is lost, causing reliability to deteriorate
Solution Approach 1:
The system performs preliminary actions by preparing memory areas and setting DMA transfer parameters in advance before the actual image data transfer is needed. The controller reserves free spaces in the memory and configures DMA transfer settings proactively, so that when high-speed reading occurs, the infrastructure is already in place to handle the data flow without interruption or need for stopping.
2Reliability
If memory free space is reserved based on worst-case scenario (no compression), then reliability is improved, but the amount of memory required increases, worsening device complexity
Solution Approach 1:
The system dynamically adjusts memory allocation and DMA transfer parameters based on the actual compression ratio achieved during encoding. Instead of statically reserving memory for the worst-case scenario, the controller monitors the compression performance and adaptively manages memory resources, allowing the same memory capacity to handle both high-compression and low-compression scenarios efficiently.
Solution Approach 2:
The system changes operational parameters (such as DMA transfer buffer sizes and memory allocation) based on the actual compression ratio. When compression performs better than expected, the system reduces the reserved memory space; when compression is poor, it increases allocation. This parameter adaptation resolves the contradiction between reliability and device complexity.
3Ease of operation
If DMA transfer settings are established before data transfer, then the transfer process is simplified, but the preparation time increases, reducing productivity
Solution Approach 1:
The controller establishes DMA transfer settings and reserves memory spaces in advance as preliminary actions, but these preparations are performed in a optimized sequence that minimizes idle time. The system configures transfer parameters and allocates memory buffers proactively during periods when the scanner is processing current frames, so that when the next frame arrives, everything is ready for immediate transfer without blocking the reading pipeline.
Data Source
AI summary
An image processing apparatus includes: a document conveyor that conveys a document; an image reader that reads an image of the conveyed document; at least one main memory; a data transfer circuit; and one or more controllers, whereas the controllers determine whether to read an image of each page in a first reading mode or a second reading mode, the first reading mode being a mode in which conveyance of the next document is started before reading of an image of a previous page is completed, the second reading mode being a mode in which conveyance of the next document starts after reading of the document of a previous page is completed, and when there is a possibility that preparation regarding image data transfer of the next page is not completed during reading in the first reading mode, the first reading mode is switched to the second reading mode.