Barcode Camera Autofocus with Coarse-to-Fine Lens Sampling
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Solution Overview
Problem
Existing barcode reading systems face inefficiencies in auto-focus mechanisms, often requiring time-consuming sweeps through numerous focus settings and being sensitive to lighting variations, leading to incorrect focusing on non-barcode regions and slow decoding processes.
Innovation Solution
A system and method that utilizes a variable lens with fine and coarse focus adjustments, measuring the depth-of-field for barcode detection, and employing high-speed liquid lenses and advanced barcode detection algorithms to rapidly locate and decode barcodes within a wide range of distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional auto-focus mechanisms sweep through numerous focus settings, then focus accuracy can be achieved, but the process becomes time-consuming and reduces productivity
Solution Approach 1:
The system performs preliminary actions by capturing images at multiple pre-determined focus settings before the actual barcode decoding process. This allows the system to pre-establish focus information across different depths, enabling rapid selection during operation without time-consuming sweeps through all possible focus settings.
Solution Approach 2:
The focus range is segmented into multiple discrete focus settings or planes. Instead of sweeping continuously through all possible focus distances, the system divides the focus range into manageable segments and captures images at each segment, then uses this segmented information for rapid barcode detection and decoding.
2Reliability
If the barcode detection process is made more robust to handle various lighting conditions, then reliability improves, but the processing time increases
Solution Approach 1:
The system performs preliminary image capture at multiple focus settings before barcode decoding is needed. This preliminary action allows the system to pre-process images for various lighting conditions and focus states, reducing the time required during actual barcode detection and decoding operations.
Solution Approach 2:
The system uses feedback from the captured images at different focus settings to determine the optimal focus plane for barcode decoding. By analyzing the captured images and using this feedback information, the system can rapidly identify the correct focus plane without time-consuming searches, improving both reliability and speed.
3Adaptability or versatility
If the focus search range is expanded to cover wider distances, then adaptability improves, but the complexity of the focus mechanism increases
Solution Approach 1:
The wide focus range is segmented into multiple discrete focus planes or settings. Instead of requiring a single complex continuous focus mechanism, the system divides the range into segments and captures images at each segment using a manageable focus mechanism, then selects the appropriate segment for barcode decoding based on the captured images.
Solution Approach 2:
The system performs preliminary image capture across the entire desired focus range at multiple discrete settings. This preliminary action allows the system to pre-establish focus information across wide distances, enabling adaptability to various distances without requiring complex real-time focus adjustment mechanisms during operation.
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 rapid and accurate focusing and decoding of barcodes by efficiently sampling lens adjustments and using high-speed liquid lenses and advanced algorithms, enhancing barcode detection speed and accuracy.
Implementation Method 1
liquid lenses that change their shape in response to changes in their shape or to changes in voltage applied to the lens
Implementation Method 2
an image sensor that acquires images of a scene containing the one or more barcodes
Data Source
AI summary
This invention provides a system and method for detecting and acquiring one or more in-focus images of one or more barcodes within the field of view of an imaging device. A measurement process measures depth-of-field of barcode detection. A plurality of nominal coarse focus settings of a variable lens allow sampling, in steps, of a lens adjustment range corresponding to allowable distances between the one or more barcodes and the image sensor, so that a step size of the sampling is less than a fraction of the depth-of-field of barcode detection. An acquisition process acquires a nominal coarse focus image for each nominal coarse focus setting. A barcode detection process detects one or more barcode-like regions and respective likelihoods. A fine focus process fine-adjusts, for each high-likelihood barcode, the variable lens near a location of the barcode-like regions. The process acquires an image for decoding using the fine adjusted setting.