Image Sensor Range and Light-Level Detection for Symbol Readers
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Solution Overview
Problem
Machine-readable symbol readers face challenges in capturing images of both non-self-illuminating and self-illuminating objects due to over-exposure from active light sources and reflective surfaces, leading to false positives and negatives when transitioning between reading modes based on image characteristics.
Innovation Solution
A method and apparatus that use a range and light-level detector to determine if an object is within a threshold range and emits sufficient ambient light, allowing the reader to selectively stop the active light source and capture images without illumination, transitioning between active illuminated and self-illuminated object reading modes based on detected conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the active light source is used to illuminate objects, then images of non-self-illuminating objects can be captured, but images of self-illuminating objects become over-exposed and saturated
Solution Approach 1:
The system dynamically adjusts the illumination state by transitioning between active illuminated mode and self-illuminated object mode based on real-time detection of object characteristics. The controller monitors image characteristics and automatically switches the active light source on or off to prevent over-exposure while maintaining capture capability for both object types.
Solution Approach 2:
The system uses feedback from image characteristics detection to control the active light source. The controller analyzes the captured images and adjusts the illumination state accordingly, creating a closed-loop system that prevents over-exposure by reducing or eliminating illumination when self-illuminating objects are detected.
2Reliability
If the active light source is used to illuminate objects, then images can be captured in low-light conditions, but reflective surfaces cause false positives and negatives in mode transition
Solution Approach 1:
The system performs preliminary detection of object characteristics before capturing images. By analyzing image characteristics in advance and detecting the presence of self-illuminating objects, the system proactively adjusts the illumination state to prevent over-exposure and mode transition errors caused by reflective surfaces.
Solution Approach 2:
The system continuously monitors image characteristics and uses this feedback to adjust the active light source state. This closed-loop control enables accurate distinction between self-illuminating and non-self-illuminating objects, preventing false positives and negatives in mode transition even when reflective surfaces are present.
3Adaptability or versatility
If the reader transitions between active illuminated and self-illuminated object reading modes based on image characteristics, then both object types can be read, but a large number of false positives and false negatives occur
Solution Approach 1:
The system performs preliminary analysis of image characteristics before executing mode transitions. By pre-processing and analyzing the captured images to identify self-illuminating objects, the system makes more accurate mode transition decisions and reduces false positives and negatives.
Solution Approach 2:
The system uses continuous feedback from image characteristic analysis to control mode transitions. The controller monitors the captured images and adjusts the reading mode accordingly, creating a reliable feedback loop that minimizes false transitions while maintaining the ability to handle both object types.
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 approach reduces false positives and negatives by accurately determining the need for active illumination, enhancing the performance of machine-readable symbol readers in capturing images from both types of objects without saturating the image sensor.
Implementation Method 1
The first transducer may include a time-of-flight transducer that detects range using a time-of-flight measurement
Implementation Method 2
The second transducer may include a light sensor that detects a level of light in the field-of-view
Data Source
AI summary
Systems and methods for selectively illuminating objects located within the field-of-view of an image sensor used to capture images in a machine-readable symbol reader. In an active illuminated reading mode, a light source illuminates objects as the image sensor captures images. In a self-illuminated object reading mode, used to capture images of smartphone, tablet, or other self-illuminating displays, the image sensor captures images without the light source illuminating the objects. The machine-readable symbol reader transitions between the two modes based upon distance and light-level measurements taken of the various objects that are within the field-of-view of the image sensor.