Adaptive Boundary Threshold for Ink Saving Mode
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Solution Overview
Problem
Ink saving mode in liquid ejection apparatuses fails to reduce ink usage effectively when printing images with characters, as the density gradient threshold is not adequately adjusted, leading to non-detection of boundary regions and increased ink usage due to unchanged droplet sizes.
Innovation Solution
An image data processing apparatus with a mode information receiving device and controller that adjusts image density values and boundary determination thresholds based on recording modes, ensuring accurate detection of boundary pixels even at reduced density levels, thereby adjusting droplet sizes accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the density level is uniformly reduced in ink saving mode, then the amount of ink used is reduced and color intensity is decreased, but the density gradient is also uniformly lowered causing boundary region detection to fail
Solution Approach 1:
The patent applies dynamics by making the boundary determination threshold adaptive rather than fixed. The threshold is dynamically adjusted based on the recording mode (ordinary mode vs. ink saving mode). When ink saving mode is detected, a lower threshold is applied to compensate for the uniformly reduced density gradient, enabling reliable boundary detection despite the overall density reduction. This dynamic adjustment resolves the contradiction between ink reduction and boundary detection accuracy.
Solution Approach 2:
The patent changes the parameter of the boundary determination threshold based on the recording mode. In ordinary mode, a first (higher) threshold is used, while in ink saving mode, a second (lower) threshold is applied. This parameter change allows the system to maintain effective boundary detection across different operating conditions, specifically addressing the issue where uniform density reduction in ink saving mode would otherwise cause boundary detection failures.
2Device complexity
If the density gradient threshold is not adjusted in ink saving mode, then the processing is simpler, but boundary pixels are not detected leading to unchanged droplet sizes and increased ink usage
Solution Approach 1:
The system dynamically selects the appropriate threshold based on the recording mode parameter. The controller detects whether ink saving mode is active and automatically applies the corresponding threshold value. This dynamic approach adds minimal processing complexity while effectively preventing the ink waste that would result from failed boundary detection.
Solution Approach 2:
The patent implements parameter changes by storing multiple threshold values (first threshold for ordinary mode, second threshold for ink saving mode) and selecting the appropriate one based on the operational mode. This simple parameter switching mechanism avoids the complexity of real-time threshold optimization while ensuring correct boundary detection and appropriate ink usage in each mode.
3Ease of operation
If the density gradient threshold is not adjusted in ink saving mode, then the system operation is simpler, but boundary detection fails causing image contour blurring
Solution Approach 1:
The system employs dynamic threshold selection that automatically adapts to the recording mode. The controller simply checks the operational mode and applies the corresponding pre-determined threshold, maintaining ease of operation. This dynamic adaptation ensures that boundary detection accuracy and image contour sharpness are preserved in ink saving mode without requiring complex real-time adjustments.
Solution Approach 2:
The patent uses parameter changes by implementing mode-specific threshold values. The first threshold is used in ordinary mode and the second (lower) threshold is used in ink saving mode. This straightforward parameter switching maintains operational simplicity while preventing contour blurring that would otherwise occur due to the uniformly reduced density gradient in ink saving mode.
Data Source
AI summary
Image boundary detection devices and methods include processes. Processes include setting an image recording mode to a second recording mode. First and second recording modes utilize first and second density values, respectively. Second density values are less than corresponding first density values. Processes include reducing first density values to second density values when the second recording mode is set. Processes include setting an image boundary determination threshold to one of a first and second threshold value when a respective one of the first and second recording mode is set. The second threshold value is less than the first threshold value. Processes include calculating density gradient values based on one of the first and second density value when the respective one of the first and second recording mode is set. Processes include determining whether pixels are image boundaries using density gradient values and the image boundary determination threshold.