Imaging Device Depth Selectivity via Phase-Shifted Code Segmentation
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Solution Overview
Problem
Existing imaging technologies cannot acquire images or range images at arbitrary distances, limiting their ability to detect objects at specific depths and differentiate between objects at varying distances.
Innovation Solution
An imaging device and method that utilize weighted addition of unit codes with shifted phases for irradiation and reference codes, allowing for controlled depth selectivity by generating irradiation codes that maximize cross-correlation with reference codes at specific distances, enabling the detection of objects at intended depths and reducing transition widths for precise imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional imaging technologies are used, then imaging is possible, but depth selectivity is insufficient and objects at arbitrary distances cannot be acquired
Solution Approach 1:
The imaging device segments the depth range into multiple selectable distance ranges by using multiple irradiation codes with different phase shifts. Each code corresponds to a specific depth range, allowing the system to selectively image objects at arbitrary distances by choosing the appropriate code segment that matches the target depth range.
Solution Approach 2:
The system changes the phase shift parameter of the irradiation codes to achieve depth selectivity. By adjusting the phase shift amount of each irradiation code relative to the reference code, the system can tune the correlation detection to maximize response at specific distances, thereby enabling arbitrary distance acquisition while maintaining high depth selectivity.
2Measurement precision
If weighted addition of unit codes with phase shifts is used, then depth selectivity is improved, but device complexity increases
Solution Approach 1:
The system employs periodic phase-shifting of irradiation codes in a systematic manner. Multiple unit codes are generated by applying periodic phase shifts to a basic code, and these are weighted and added together. This periodic approach simplifies the generation process compared to creating entirely unique codes for each depth range, reducing device complexity while maintaining depth selectivity.
Solution Approach 2:
The system performs preliminary generation of unit codes with predetermined phase shifts and weights. These pre-calculated codes are stored and selectively combined based on the desired depth range, avoiding the need for complex real-time code generation during operation. This preliminary preparation reduces the computational burden and device complexity during actual imaging.
3Adaptability or versatility
If multiple irradiation codes with different phase shifts are used, then arbitrary distance imaging is enabled, but transition width increases causing unwanted reflections
Solution Approach 1:
The system applies local quality optimization by using different phase shift amounts and weights for different unit codes corresponding to different depth ranges. Each code is locally optimized to maximize correlation at its specific target distance while minimizing responses at other distances, thereby reducing unwanted reflections from objects outside the intended depth range while maintaining arbitrary distance acquisition capability.
Solution Approach 2:
The system converts the potential harmful effect of multiple codes (which could cause increased transition width and unwanted reflections) into a benefit by carefully designing the phase shifts and weights. The weighted addition of phase-shifted codes creates constructive interference at the target distance and destructive interference at other distances, transforming what could be harmful broad transitions into beneficial sharp depth selectivity.
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 the acquisition of images or range images at arbitrary distances, improving depth selectivity and reducing unwanted reflections, allowing for accurate detection and photography of objects within specific depth ranges.
Implementation Method 1
The present technology relates to an imaging device and an imaging control method and specifically relates to an imaging device and an imaging control method using a time of flight (ToF) method.
Implementation Method 2
a technology of transmitting a transmission signal modulated by a predetermined PN code in a predetermined direction from a vehicle identification device
Data Source
AI summary
An imaging device includes: a control unit configured to control an output of an irradiation signal including an irradiation code used for control of a pattern of emission of irradiation light and an output of a reference signal including a reference code indicating a pattern used for detection of a correlation with reception light including reflection light of the irradiation light; and an imaging element configured to output a pixel signal indicating a correlation between the reception light and the reference signal, wherein one of the irradiation code and the reference code is a code in which weighted adding of a plurality of unit codes, in which a phase of a basic code having an impulse cross-correlation with the other code is shifted for a different shift amount, is performed.