Real-Time Document Skew Detection in Image Scanning Apparatus
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image scanning apparatuses are unable to detect the skew angle of a document sheet during the conveyance process, as they calculate the skew angle before image scanning and rely on pre-existing detection signals from sensors.
Innovation Solution
An image scanning apparatus with a document tray, conveyor, distance detectors, and a controller that determines and stores positions based on detection signals from the distance detectors to calculate the skew angle of the document sheet in real-time during conveyance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the skew angle is calculated based on detection signals from sensors arranged side by side along the main scanning direction before image scanning, then the skew angle can be determined in advance, but the skew angle of the document sheet being conveyed cannot be detected in real-time
Solution Approach 1:
The patent applies preliminary action by detecting the position of the side end of the document sheet at multiple predetermined positions along the conveyance direction before the image scanner reaches it. The controller stores these position measurements and then calculates the skew angle based on the stored position information and the known distances between detection points, enabling real-time skew detection during conveyance rather than only before scanning.
2Productivity
If two sensors are arranged side by side along the main scanning direction to detect the leading end, then the skew angle can be calculated from the time difference, but the detection occurs before image scanning and not during conveyance
Solution Approach 1:
The patent segments the skew detection process into multiple discrete position measurements along the conveyance direction. Instead of using a single time-difference measurement from two sensors, the controller measures the position of the side end at multiple predetermined locations (first position, second position, etc.) and uses these segmented measurements to calculate the skew angle, improving reliability by using multiple data points throughout the conveyance process.
Solution Approach 2:
The patent introduces position information as an intermediary element between the physical side end of the document sheet and the skew angle calculation. The controller measures the position of the side end relative to predetermined positions along the conveyance direction, uses this position information as intermediate data, and then calculates the skew angle based on the relationship between these position measurements and the known distances between detection points.
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
Enables the detection and correction of skew angles in real-time during the scanning process, improving the accuracy of scanned images by calculating the skew angle based on the positions of the document sheet's side ends relative to the conveyance direction.
Implementation Method 1
at least one distance detector configured to output a detection signal having a value corresponding to a distance in the main scanning direction from a particular position to a side end of the document sheet being conveyed by the conveyor
Data Source
AI summary
An image scanning apparatus includes a distance detector configured to output a detection signal having a value corresponding to a distance in a main scanning direction from a particular position to a side end of a document sheet being conveyed, and a controller configured to store a first position of the document sheet in a conveyance direction when the distance detector outputs a detection signal having a first value corresponding to a first particular distance, store a second position of the document sheet in the conveyance direction when the distance detector outputs a detection signal having a second value corresponding to a second particular distance, and calculate a skew angle of the document sheet based on the first position and the second position.