Image Inspection Test Chart with Density Patches
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Solution Overview
Problem
The accuracy of image quality inspection on printing media is reduced due to reflection effects from surrounding regions during the reading process, which degrades the correction parameter calculation and overall inspection accuracy.
Innovation Solution
An image forming system that includes a reading apparatus with a light-emitting unit and a sensor, using a test chart with light and dark patch images of varying densities to minimize reflection effects, and a processor to control the formation of the test chart and inspect images based on RIP data, thereby reducing the impact of reflection on image inspection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a scanner reads a test chart to calculate correction parameters, then the inspection process can be performed, but reflection from surrounding regions degrades the accuracy of the correction parameter
Solution Approach 1:
The test chart is designed with different density characteristics in different regions. Light patch images have lower density while dark patch images have higher density, creating local quality variations that allow the reading apparatus to measure and compensate for reflection effects specifically at each location, thereby improving overall inspection accuracy.
Solution Approach 2:
The test chart acts as an intermediary element between the reading apparatus and the actual printing medium. By including known patterns with specific density characteristics, the test chart enables calculation of correction parameters that mediate the reflection effects, allowing accurate measurement of the actual printing medium without the harmful reflection interference.
2Ease of manufacture
If a test chart with uniform density is used, then the reading process is simple, but the accuracy of correction parameter calculation is reduced due to reflection
Solution Approach 1:
Instead of using uniform density throughout, the test chart incorporates regions with different density characteristics (light and dark patches). This local variation in density allows the reading apparatus to capture reflection information and calculate accurate correction parameters, while still maintaining the simplicity of a standardized chart format.
Solution Approach 2:
The test chart utilizes changes in density parameters across different regions. By varying the density of patches (light vs. dark), the system creates measurable differences that enable calculation of reflection effects and correction parameters, transforming a potentially problematic uniform structure into an informative varied structure.
3Device complexity
If the reading apparatus uses a simple reading unit, then the device complexity is low, but reflection effects cannot be compensated
Solution Approach 1:
The reading apparatus performs self-calibration by automatically reading the test chart and calculating correction parameters based on the known density characteristics of the light and dark patches. This self-service capability allows the simple reading unit to compensate for reflection effects without requiring complex external calibration equipment or manual intervention.
Solution Approach 2:
The system incorporates feedback through the test chart reading process. The reading apparatus measures the actual density values of light and dark patches, compares them against expected values, and uses this feedback to calculate correction parameters that compensate for reflection effects, thereby improving inspection accuracy while maintaining simple hardware.
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
The system enhances the accuracy of image position adjustment and quality inspection by minimizing reflection effects, leading to improved correction parameter calculation and increased inspection accuracy.
Implementation Method 1
a sensor configured to receive light emitted by the light-emitting unit and reflected by the printing medium
Data Source
AI summary
An image forming system includes: a background member of a black color provided at an opposite side to a reading unit with respect to a conveyance path; and at least one processor configured to form a test chart on a first printing medium based on RIP data corresponding to the test chart, and inspect an inspection target image formed on a second printing medium by an image forming apparatus based on first image data obtained by reading the inspection target image formed on the second printing medium and the RIP data corresponding to the inspection target image. The test chart includes light patch images and dark patch images surrounding the light patch images, and each one of the light patch images and the dark patch images has different density.