Optical Code Scanner Depth of Field via Dual Focal Points
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Solution Overview
Problem
Conventional optical code scanners face limitations in increasing the depth of field without reducing light intensity, which affects their ability to reliably read bar codes over a larger volume of space.
Innovation Solution
The use of a lens configured to focus light to two different focal points, combined with an adjustable aperture controlled by software, allows for optimal light management and image capture, enhancing the depth of field while maintaining sufficient light intensity for reliable decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the size of the optical aperture is reduced to increase the depth of field, then the depth of field is improved, but the light intensity available for capturing the bar code image is reduced
Solution Approach 1:
The patent employs dynamic aperture adjustment where the aperture size is varied during the image capture process. The controller opens the aperture to a first size during a first time period to capture sufficient light, then closes it to a second size during a second time period to increase depth of field. This dynamic adjustment allows the system to sequentially achieve both high light intensity and large depth of field that would be mutually exclusive with a static aperture setting.
Solution Approach 2:
The patent implements periodic action by capturing multiple images at different aperture settings over different time periods. The controller alternates between opening the aperture to capture light and closing it to increase depth of field, creating a periodic cycle of aperture adjustment. This periodic action allows the system to accumulate sufficient light information while maintaining the depth of field benefits during critical capture phases.
2Illumination intensity
If the aperture is kept open to maintain light intensity, then the light availability is improved, but the depth of field is reduced making it difficult to reliably read bar codes at various distances
Solution Approach 1:
The patent employs dynamic aperture adjustment where the aperture size is varied during the image capture process. The controller opens the aperture to a first size during a first time period to capture sufficient light, then closes it to a second size during a second time period to increase depth of field. This dynamic adjustment allows the system to sequentially achieve both high light intensity and large depth of field that would be mutually exclusive with a static aperture setting.
Solution Approach 2:
The patent implements periodic action by capturing multiple images at different aperture settings over different time periods. The controller alternates between opening the aperture to capture light and closing it to increase depth of field, creating a periodic cycle of aperture adjustment. This periodic action allows the system to accumulate sufficient light information while maintaining the depth of field benefits during critical capture phases.
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 significantly increases the depth of field, enabling the reliable detection and decoding of optical codes over a larger range of distances without compromising image clarity or light availability.
Implementation Method 1
using a lens configured to focus incoming light from an optical code to two different focal points where the focused light is then captured by an image capture device
Implementation Method 2
an aperture is used to adjust the amount of light transmitted from the optical code to the lens
Data Source
AI summary
An apparatus, system and method are presented for extending the depth of field of an optical code image scanner. The optical code image scanner comprises a lens and an image capture device where the lens is configured to create two distinct focal points using incoming light and the image capture device captures an image using light from the lens.