Printed Image Spectral Position Verification Using Imaging Sensors
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Solution Overview
Problem
Spectrophotometers in printing presses cannot visually capture the image area and are prone to positional variations of the printed substrate, making it impossible to verify whether the intended pixel or image section was actually captured, leading to inaccurate color measurements due to potential spatial differences.
Innovation Solution
A method involving a spectrophotometer and an imaging sensor to simultaneously or sequentially capture detection areas within a printed image, comparing the actual image data with predefined target areas to validate the position and reject spectral data if a positional deviation exceeds a limit, ensuring accurate color evaluation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a spectrophotometer is used to record spectral data of the print image, then colorimetric data and color perception can be determined precisely, but the image section cannot be captured and positional deviations cannot be verified
Solution Approach 1:
The patent combines a spectrophotometer and an imaging sensor into a single measurement device. The spectrophotometer captures spectral data for color analysis while the imaging sensor simultaneously captures image section information, merging two previously separate functions into one integrated system that resolves the contradiction between precise color measurement and image capture capability.
Solution Approach 2:
The measurement device is designed with multi-functionality, serving both as a spectrophotometer for colorimetric analysis and as an imaging sensor for capturing image sections. This universal device can perform multiple functions (color measurement, image capture, position verification) that were previously requiring separate devices, thereby eliminating the loss of image section information.
2Productivity
If spectral data is recorded at full production speed, then productivity is maintained, but positional deviations between intended and actual capture positions cannot be detected
Solution Approach 1:
By merging the imaging sensor with the spectrophotometer, the system can simultaneously maintain full production speed spectral recording while incorporating image section capture for position verification. The combined device processes both types of data in parallel, enabling position verification without compromising productivity.
Solution Approach 2:
The imaging sensor provides real-time feedback on the actual position of the captured image section relative to the intended position. This feedback mechanism allows the system to detect positional deviations during production and adjust accordingly, maintaining both speed and accuracy through continuous monitoring and correction.
3Measurement precision
If color density values are determined from reflectance, then color density can be measured, but no information about color perception or compliance with color values is provided
Solution Approach 1:
The patent transforms the measurement approach by changing from direct color density measurement to spectral data acquisition. By recording the full spectral reflectance curve and converting it to colorimetric data (LAB values), the system gains comprehensive color perception information while maintaining color density measurement capability. This parameter transformation enables both density measurement and color perception analysis.
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
Ensures reliable determination of actual spectral data capture at the intended pixel or image section, preventing inaccurate color corrections and allowing for timely corrective actions and continuous quality control in printing processes.
Implementation Method 1
Spectrophotometers have the property of detecting the wavelengths of the light reflected from the image point to be captured
Implementation Method 2
an imaging sensor (4) ... detecting a second detection area (3-2) in the print image (2)
Data Source
Figure 1~2
Figure 3a~3b
Figure 4a~4b
AI summary
The invention relates to a method for evaluating spectral data of a printed image (2) applied to a substrate (1), wherein the printed image (2) is represented by digital image data (12). The object of the invention is to determine the actual position of the first detection area (3-1) actually detected by a spectrophotometer (7). This object is achieved by a method comprising the following steps: a) defining at least one target area (13) located in the printed image (2), b) detecting a first detection area (3-1) located in the printed image (2) and corresponding to the first target area (13-1) using a spectrophotometer (7) and determining actual spectral data of the first detection area (3-1), c) simultaneously or sequentially detecting the second detection area (3-2) corresponding to the target area (13) located in the printed image (2).d) Comparing the actual image data acquired by the imaging sensor (4) with the image data (12) and determining the position of the second detection area (3-2) in the printed image (2), e) Determining the position of the first detection area (3-1) in the printed image based on the position of the second detection area (3-2) in the printed image (2) and a defined position difference xd,yd between the first detection area (3-1) and the second detection area (3-2). This solution has the advantage that it reliably determines whether the measurement was actually taken at the intended pixel or image section.