Barcode Scanner Distance Estimation Using Extended Aiming Pattern
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Imaging-based barcode scanners face challenges in accurately determining the distance between the scanner and the target object, which affects focus and resolution, especially when using variable focus lengths and zoom settings.
Innovation Solution
The apparatus includes an aiming pattern generating element and an aiming light source to project an extended aiming pattern, which is detected by an imaging sensor to estimate the feature-size of the pattern. This feature-size, along with predetermined focus and zoom settings, is used to determine the distance between the target object and the scanner, allowing for adjustment of the imaging lens arrangement for optimal focus and resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If variable focus lengths and zoom settings are used in imaging-based barcode scanners, then the scanner can accommodate different scanning distances and magnification levels, but the ability to accurately determine the distance between the scanner and the target object deteriorates
Solution Approach 1:
The patent introduces an intermediary aiming pattern (crosshair or reticle) that is superimposed on the barcode image. This pattern serves as a reference marker that allows the system to calculate distance by comparing the known size of the pattern with its apparent size in the captured image, thereby resolving the distance measurement accuracy problem while maintaining variable focus and zoom capabilities
Solution Approach 2:
The patent creates a virtual copy of the aiming pattern in the captured image data. By detecting the position and dimensions of this pattern copy within the image, the system can infer distance information without requiring direct physical measurement, thus enabling accurate distance determination across variable focus lengths and zoom settings
2Adaptability or versatility
If the imaging lens arrangement is adjusted for different focus lengths, then the scanner can focus on objects at various distances, but the resolution and focus accuracy for barcode imaging deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the detected position of the aiming pattern in the captured image is used to calculate the actual focus distance. This feedback information is then fed back to the lens control system to automatically adjust the focus length, ensuring that the imaging lens is correctly focused on the barcode at any given distance while maintaining high resolution and focus accuracy
3Adaptability or versatility
If the imaging sensor captures images at different zoom levels, then the scanner can read barcodes at various sizes and distances, but the measurement precision of the target object dimensions deteriorates
Solution Approach 1:
The aiming pattern serves as a reference intermediary that maintains known dimensional characteristics regardless of zoom level. By detecting the pattern's apparent size in the captured image at any zoom level, the system can calculate the actual distance to the barcode and compensate for zoom variations, thereby maintaining measurement precision of object dimensions across different zoom settings
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 accurate determination of the object-scanner distance, ensuring proper focus and resolution for barcode imaging, improving the scanning process by allowing for precise adjustment of the imaging lens settings based on the detected distance.
Implementation Method 1
an aiming light source configured to project visible light through the aiming pattern generating element to generate an extended aiming pattern on a target object
Implementation Method 2
an imaging sensor having photosensitive elements for detecting light from the target object through an imaging lens arrangement to create first pixel data
Data Source
AI summary
An apparatus includes an imaging sensor having photosensitive elements for detecting light from the target object through an imaging lens arrangement to create first pixel data during a first time period when the extended aiming pattern is projected on the target object. The apparatus also includes a controller for processing the first pixel data to estimate a feature-size of the extended aiming pattern in an image of the target object when the imaging lens arrangement is at a predetermined focus length, and further processing the feature-size along with the predetermined focus length to determine a distance characterizing the separation between the target object and the imaging lens arrangement.