Blank Page Detection Using Image Tile Segmentation and Compression Flags
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Solution Overview
Problem
Conventional image forming apparatuses face inefficiencies in determining whether an image is a blank sheet, leading to increased processing time and potential determination errors due to software-based scanning of color information and reliance on compression rates, which can confuse black and white sheets with similar compression rates.
Innovation Solution
An image forming apparatus that detects continuous ranges of identical image data, specifies image data of interest, and determines whether a page is a blank sheet using a combination of repeat flags and compression rates, allowing for hardware-independent and accurate blank sheet determination without adding new hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If software processing is used to scan color information of all sequentially generated image data, then blank sheet determination can be performed, but the process time increases
Solution Approach 1:
The patent divides the page into multiple small areas (tiles) and processes them sequentially. For each tile, it checks repeat flags to identify continuous ranges of identical image data, then only scans color information for representative tiles in each continuous range rather than all tiles, significantly reducing processing time while maintaining determination accuracy
Solution Approach 2:
The patent performs preliminary compression of image data before blank sheet determination. The compression process generates repeat flags that indicate continuous ranges of identical data. By utilizing this preliminary compression result, the system avoids redundant scanning of color information for identical tiles, thereby reducing process time without sacrificing accuracy
2Reliability
If uncompressed image data is prepared to scan color information, then blank sheet determination can be performed, but memory capacity requirement increases
Solution Approach 1:
The patent performs preliminary compression of image data into a compressed format (e.g., JPEG) before blank sheet determination. The compression process generates repeat flags that mark continuous ranges of identical tiles. By working with compressed data and using repeat flags to identify which tiles need color scanning, the system maintains determination accuracy while using minimal memory capacity
Solution Approach 2:
The patent extracts only the necessary information for blank sheet determination from the compressed image data. Instead of decompressing and storing all color information, it selectively scans color data only for representative tiles in continuous ranges identified by repeat flags, thereby reducing memory requirements while preserving determination accuracy
3Device complexity
If determination is done using PDL data interpretation without solving depth information, then processing is simplified, but determination errors may occur
Solution Approach 1:
The patent replaces complex mechanical/PDL interpretation-based determination with a simpler image-based approach. It uses repeat flags from compressed image data to identify continuous ranges of identical tiles, then scans color information of representative tiles to determine if the page is blank. This substitution maintains low processing complexity while improving determination accuracy by directly analyzing image content rather than relying on PDL interpretation
Solution Approach 2:
The patent performs partial scanning of color information instead of scanning all tiles. By using repeat flags to identify continuous ranges of identical tiles, it only scans color data for representative tiles in each range, achieving sufficient determination accuracy with reduced processing complexity and avoiding the need for complete PDL interpretation
4Productivity
If blank sheet determination is done by hardware, then processing speed increases, but apparatus cost rises
Solution Approach 1:
The patent makes the existing image compression hardware serve a dual purpose: it compresses image data for storage/transmission and simultaneously generates repeat flags that enable fast blank sheet determination. By utilizing the self-generated repeat flag information from the compression process, the system achieves hardware-speed determination without adding separate hardware circuits, thereby maintaining processing speed while avoiding increased apparatus cost
Solution Approach 2:
The patent makes the image compression hardware multi-functional. The same compression unit that compresses image data also generates repeat flags that are used for blank sheet determination. This universal use of existing hardware achieves fast processing speed without requiring additional dedicated hardware circuits, thereby avoiding increased apparatus cost
5Device complexity
If compression rate is used to determine blank sheets, then processing is simplified, but determination errors occur because black and white sheets have similar compression rates
Solution Approach 1:
The patent divides the page into multiple small area tiles and uses repeat flags to identify continuous ranges of identical tiles. By segmenting the image and selectively scanning color information of representative tiles in each continuous range, it can accurately distinguish between black and white sheets based on their actual color content rather than compression rate, maintaining simple processing while improving determination accuracy
Solution Approach 2:
The patent performs partial scanning of color information for representative tiles in continuous ranges identified by repeat flags, rather than scanning all tiles or relying on compression rate. This partial action provides sufficient information to accurately distinguish black and white sheets while keeping processing complexity low, overcoming the limitation of compression rate-based determination
Data Source
AI summary
An image forming apparatus for generating image data of a page divided into small areas continuously in a predetermined direction and forming an image based on the image data, includes a detection unit configured to detect a continuous range of the image data having the same image contents in the page, the page including at least one continuous range, a specifying unit configured to specify image data of interest in the continuous range of the image data detected by the detection unit, and a first determination unit configured to determine based on the image data of interest whether the page is a blank sheet.