Imaging Reader Trajectory Target Identification
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Solution Overview
Problem
Existing imaging readers face difficulties in accurately reading a selected symbol target from a picklist due to the diverging imaging field of view, which often contains multiple targets, especially at farther working distances, leading to sluggish performance and increased processing burden by requiring multiple image captures.
Innovation Solution
An apparatus and method that store coordinates of an aiming light pattern's trajectory within the imaging field of view, allowing the controller to determine if a target covers this trajectory, and if partially covered, search outside the target to identify the selected target without energizing the aiming light assembly, thereby reducing the need for dual image captures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the imaging field of view is used to capture targets at far working distances, then the reading range is extended, but multiple targets are captured causing reduced accuracy and increased processing burden
Solution Approach 1:
The patent divides the imaging field of view into multiple regions along the optical axis, creating distinct capture zones for different working distances. The controller processes images by analyzing which region contains the target, allowing accurate identification even when multiple targets are visible in the overall field of view.
Solution Approach 2:
The patent introduces an aiming light pattern as an intermediary element that projects onto the target area. This light pattern serves as a visual guide and spatial marker that helps the controller distinguish the selected target from other targets in the field of view, enabling accurate identification without requiring dual image captures.
2Measurement precision
If dual image captures are performed to identify the selected target, then target identification accuracy is improved, but processing time increases and reading speed decreases
Solution Approach 1:
The patent performs preliminary action by projecting the aiming light pattern onto the target area before image capture. This pre-positioning guide helps the controller immediately identify the selected target in the captured image without needing to perform additional capture operations, thereby maintaining both accuracy and speed.
Solution Approach 2:
The aiming light pattern acts as an intermediary that provides spatial information about the selected target's location. By analyzing the interaction between the light pattern and the captured image, the controller can quickly and accurately identify the selected target without requiring multiple image captures, thus improving reading speed while maintaining accuracy.
3Measurement precision
If the aiming light assembly is energized to project patterns on targets, then target location accuracy is improved, but energy consumption increases
Solution Approach 1:
The patent implements periodic action by energizing the aiming light assembly only during specific phases of the reading process when target location assistance is needed. The light pattern is projected, images are captured, and then the light assembly is deenergized, creating a cyclic operation that provides location accuracy when required while minimizing continuous energy consumption.
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
Enhances reading performance by accurately identifying the selected target without the need for dual image captures, reducing processing burden and improving reading speed by directly processing the captured image along the trajectory.
Implementation Method 1
a solid-state imager (or image sensor) with a sensor array of photocells or light sensors (also known as pixels), and an imaging lens assembly for capturing return light scattered and/or reflected from the target being imaged
Implementation Method 2
an illuminating light assembly for illuminating the target with illumination light for reflection and scattering therefrom. The illumination light preferably is distributed along an illumination pattern over and along the target. The distributed illumination pattern is typically generated by using a pair of spaced-apart light emitting diodes (LEDs)
Implementation Method 3
The aiming light assembly includes an aiming light source, such as one or more LEDs and aiming lenses
Implementation Method 4
an aiming light source, such as one or more LEDs and aiming lenses, or a laser and a pattern shaping optical element
Implementation Method 5
a pattern shaping optical element, such as a diffractive optical element (DOE), or a refractive optical element (ROE). The focused light passing through a respective DOE forms multiple diverging beamlets
Data Source
AI summary
A selected target from a picklist having a plurality of targets is electro-optically read, by image capture, over a range of working distances, by capturing an image of the picklist in the range over an imaging field of view, by storing coordinates of a trajectory of an aiming light pattern in the imaging field of view over the range, by processing the captured image along the trajectory to find and identify a target, by determining whether the target covers the trajectory, and by determining that the target is the selected target when the target at least partially covers the trajectory.