Flatbed Scanner Thickness Detection via Dual Light Irradiation
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Solution Overview
Problem
Existing image scanning devices face challenges in accurately scanning documents of varying thickness due to light source degradation and positional differences when using both automatic document feeders and flatbed scanners, leading to inconsistent image data and potential 'whiteout' phenomena.
Innovation Solution
An image scanning device with a transparent plate member, a sensor emitting light from below, and a holding member with a gray lower surface, which calculates a difference value from two light amounts to determine the scanning mode based on reflected light, reducing variations caused by light source degradation and positional differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single light irradiation is used to scan document thickness, then the scanning process is simple and fast, but the image data varies due to light source degradation and positional differences
Solution Approach 1:
The patent applies periodic action by performing multiple light irradiations at different positions (first irradiation at first position, second irradiation at second position) to obtain multiple image data sets. This periodic measurement approach allows the system to capture variations in reflected light intensity caused by light source degradation and positional differences, enabling more reliable thickness estimation through comparison of the multiple measurements.
2Measurement precision
If multiple light irradiations are performed to improve thickness estimation accuracy, then image data consistency improves, but the scanning process becomes more complex and time-consuming
Solution Approach 1:
The patent applies universality by using the same sensor to perform multiple functions: it scans both the thickness of the original document and the image content of the document. The sensor and light source are reused across multiple irradiations rather than introducing separate dedicated thickness measurement devices, thereby improving measurement precision without significantly increasing device complexity.
3Ease of operation
If the sensor scans thin documents with standard light intensity, then the scanning process is simple, but the reflected light is too large causing the image density to become too thin
Solution Approach 1:
The patent applies dynamics by making the light source intensity adjustable and adaptive. The system dynamically adjusts the light emission intensity based on the detected document thickness: using lower intensity for thin documents to prevent excessive reflected light and maintain proper image density, and higher intensity for thick documents to ensure sufficient light penetration. This dynamic adjustment resolves the contradiction between operational simplicity and image quality.
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
This approach allows for accurate thickness estimation and reduced 'whiteout' occurrences by determining the optimal scanning mode based on image difference values, ensuring consistent image quality across different document thicknesses and scanning positions.
Implementation Method 1
a light source configured to emit light toward the plate member from below
Implementation Method 2
receive reflected light which is light emitted by the light source and reflected by the original document placed on the plate member
Data Source
AI summary
An image scanning device according to aspects of the present disclosures includes a transparent plate member on which an original document can be placed, a line sensor configured to receive a light emitted from a light source and reflected by the original document, and output an electrical signal according to the reflected light, a holding member configured to cover an upper surface of the plate member, and a controller. The controller is configured to obtain a first electrical signal corresponding to a first reflected light when the light source emits light having a first light amount, obtain a second electrical signal corresponding to a second reflected light when the light source emits light having a second light amount, and determine a particular scanning mode for scanning the original document placed on the plate member based on an image difference value calculated from the first and second electrical signals.