Hybrid Area-Linescan Imaging for Bottom-Surface Code Reading
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Solution Overview
Problem
Checkout systems face difficulties in accurately reading optical codes on the bottom surface of items due to wobbling motion and the limited read region defined by a gap between conveyor elements, leading to inefficiencies and potential distortion in image capture.
Innovation Solution
An automated checkout system employing a dual-camera setup with one camera operating in area mode and another in linescan mode, positioned beneath the conveyor to capture optical codes as items pass through a narrow gap, ensuring accurate decoding by stitching together area and linescan views to reconstruct the complete image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single imaging reader operates in linescan mode to capture optical codes on the bottom surface, then the system can read codes during item movement, but erratic motion or wobbling of the item results in distorted images that prevent accurate decoding
Solution Approach 1:
The patent combines two different imaging modes (area mode and linescan mode) into a single hybrid system. The area mode camera captures the entire code field of view in a single frame, while the linescan mode camera captures sequential lines that are stitched together. This merging allows the system to leverage the motion-tolerance of area mode while maintaining the continuous capture capability of linescan mode, thereby resolving the contradiction between automated reading and image accuracy under erratic motion.
Solution Approach 2:
The system dynamically switches between or combines two different imaging approaches based on the reading requirements. By implementing both area mode and linescan mode capabilities in the same reader, the system can adapt its capture strategy to handle items with varying degrees of motion stability, thus maintaining measurement precision while preserving productivity across different operating conditions.
2Stability of the object's composition
If the read region is defined by a narrow gap between conveying elements to maintain conveyor stability, then item stability is improved, but the field of view is constrained making it difficult to capture complete optical codes
Solution Approach 1:
The patent extends the reading capability from a single narrow gap dimension to multiple dimensions by incorporating both area mode imaging (which captures a two-dimensional field of view) and linescan mode imaging (which captures sequential lines across the gap). This dimensional extension allows the system to capture complete optical codes even when the physical gap between conveying elements remains narrow, thus maintaining item stability while expanding the effective read region.
3Measurement precision
If manual processing is implemented to reposition items with codes on the bottom surface, then code reading accuracy is improved, but item processing time increases leading to inefficiencies
Solution Approach 1:
The imaging reader performs self-correction for bottom-surface code detection by automatically switching between area mode and linescan mode operation. The system can identify when a code is on the bottom surface and adjust its capture strategy accordingly, eliminating the need for manual intervention. This self-service capability maintains code reading accuracy while preventing the time loss that would result from manual repositioning operations.
4Measurement precision
If area mode imaging is used to capture complete code views, then the entire code can be captured in a single frame, but a large read region is required which is difficult to accommodate in narrow gap systems
Solution Approach 1:
The patent merges area mode imaging with linescan mode imaging to resolve the space constraint. The area mode component captures the complete code field of view when space permits, while the linescan mode component captures sequential lines that are stitched together to form the complete code image. This combination allows the system to achieve complete code capture without requiring a large physical read region, thus maintaining measurement precision while adapting to narrow gap constraints.
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 configuration enhances the accuracy and efficiency of reading optical codes on items with erratic motion, reducing errors and manual processing time by capturing clear images of codes on both top and bottom surfaces, even in constrained read regions.
Implementation Method 1
an imaging reader that employs an imaging device or sensor array, such as a CCD (charge coupled device) imager or CMOS (complementary metal oxide semiconductor) imager
Data Source
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AI summary
An automated checkout system (10) and method of operation for reading encoded data on a bottom surface (32) of an item (20) using a data reader (40). The automated checkout system (10) includes a leading conveyor section (14) and a trailing conveyor section (16) separated by a gap (18) therebetween, where the item (20) is transported across the gap (18) as it moves between the conveyors (14, 16). A first and second reading device (42, 44) are each positioned beneath the conveyor sections (14, 16), where each reading device (42, 44) has a field of view projecting through the gap (18). The first reading device (42) is configured to acquire a first set of scan data and the second reading device (44) is configured to acquire a second set of scan data different from the first. In some embodiments, the first set of scan data may include two-dimensional area views (54) of the encoded data, and the second set of scan data may include linescans (55) of the encoded data.