Sewing Machine Thickness Detection via Projected Pattern
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Solution Overview
Problem
Existing sewing machines struggle to accurately detect the thickness of unpressed work cloths, especially quilted materials with cotton batting, and require complex operations to position the cloth for thickness detection, with limited detection areas when using light reflection methods.
Innovation Solution
A sewing machine equipped with a projector that creates a projection image with a characteristic point and an image capture system to compute the thickness of the sewing object without pressing, allowing for simple operation and accurate projection of patterns based on computed thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an angle sensor is used to detect cloth thickness by pressing the work cloth, then thickness detection is possible, but the thickness cannot be detected when the work cloth is not being pressed (e.g., quilted materials with cotton batting)
Solution Approach 1:
The patent replaces the mechanical angle sensor system with an optical system consisting of a projector and image capture portion. The projector projects a pattern onto the work cloth, and the image capture portion captures the reflected light. By analyzing the distortion of the projected pattern, the system calculates cloth thickness without mechanical contact, enabling detection of quilted materials and other unpressed fabrics.
Solution Approach 2:
The patent introduces a projected pattern as an intermediary element between the detection system and the work cloth. The pattern serves as a reference that, when captured and analyzed, provides information about the cloth's surface topology and thickness. This intermediary enables non-contact measurement by translating physical cloth properties into optical signals that can be processed computationally.
2Measurement precision
If a light-emitting portion projects a beam onto the work cloth for thickness detection, then thickness can be detected based on reflected light position, but the detectable area is extremely narrow requiring complicated positioning operations
Solution Approach 1:
The patent segments the detection approach by using a structured pattern composed of multiple distinguishable features (lines, grids, or dots) rather than a single light beam. This segmentation allows the system to detect thickness at multiple locations simultaneously and automatically identify the appropriate measurement points, eliminating the need for manual positioning of a narrow detection area.
Solution Approach 2:
The patent transitions from one-dimensional point-based detection to two-dimensional pattern-based detection. By projecting a pattern that covers a broader area and capturing it with an image sensor, the system gains spatial context and can automatically analyze thickness across the entire projected area, removing the need for precise manual positioning that was required with narrow beam detection.
3Measurement precision
If an angle sensor presses the work cloth for thickness detection, then thickness measurement is achieved, but the work cloth cannot maintain its natural state (contraction, quilting structure)
Solution Approach 1:
The patent replaces the mechanical pressing action of the angle sensor with a non-contact optical measurement system. The projector and image capture portion measure thickness by analyzing light reflection patterns without applying any force to the work cloth, thereby preserving the natural state of quilted materials, cotton batting, and other fabrics that would be distorted by mechanical pressure.
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 of sewing object thickness without pressing and allows for accurate projection of patterns at specified positions, improving operational simplicity and precision in sewing operations.
Implementation Method 1
an image capture portion that is mounted in a position being different from a position of the projecting portion and that creates a captured image by image capture of the characteristic point projected by the projecting portion
Data Source
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AI summary
In a sewing machine that includes a projecting portion and an image capture portion that is mounted in a different position from the projecting portion, a projection image that is used for projecting a pattern is created (Step S40). The pattern is projected onto a sewing object based on the created projection image (Step S50). A captured image is created by capturing an image of the projected pattern (Step S60). The thickness of the sewing object is computed based on the projection image that was created in the processing at Step S40 and the captured image that was created in the processing at Step S60 (Step S80).