Optical Measurement Speckle Noise Reduction via Phase Cycling
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Solution Overview
Problem
Optical measurement systems face limitations in signal-to-noise ratio due to coherent noise sources like speckle noise, which reduces measurement accuracy.
Innovation Solution
The system employs multiple emitters with a phase shifter array to adjust the phase states of light emission, allowing emitters to cycle through target measurement states with a common phase state distribution, thereby reducing coherent noise by incoherently summing the relative contributions of each emitter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple emitters are used to increase measurement signal, then measurement accuracy improves, but coherent noise (speckle noise) increases reducing signal-to-noise ratio
Solution Approach 1:
The system dynamically changes the phase states of multiple emitters during measurement by cycling through different measurement states. This dynamic phase modulation transforms the coherent noise into incoherent noise, allowing the noise to average out over time while maintaining the measurement signal, thereby improving signal-to-noise ratio and measurement accuracy
Solution Approach 2:
The system employs periodic cycling through multiple measurement states with different phase distributions. By repeatedly switching between these states and averaging the results, the coherent speckle noise is converted to random noise that can be statistically reduced, while the underlying measurement information is preserved and enhanced
2Object-affected harmful factors
If phase states of emitters are adjusted to reduce coherent noise, then signal-to-noise ratio improves, but system complexity increases
Solution Approach 1:
The system changes the phase parameter of the light emitted by multiple emitters without altering the physical structure or adding complex components. By simply modulating the phase states cyclically and averaging the measurements, the system reduces coherent noise effectively while maintaining relatively simple hardware architecture
Solution Approach 2:
The system creates multiple copies of the measurement process using different phase states of the emitters. By cycling through different measurement states and averaging the results, the system obtains a more accurate measurement while using the same physical emitters, avoiding the need for additional complex noise-reduction hardware
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 effectively increases the signal-to-noise ratio by averaging out speckle noise, improving measurement accuracy while maintaining a balanced load on the power supply and simplifying system design.
Implementation Method 1
the controller is configured to change, during the simultaneous emission of the generated light, the measurement state between a plurality of target measurement states having a common phase state distribution
Implementation Method 2
The launch group includes a plurality of emitters optically coupled to the light generation assembly to receive light generated by the light generation assembly
Data Source
AI summary
Embodiments are directed to optical measurement systems that utilize multiple emitters to emit light during a measurement, as well as methods of performing measurements using these optical measurement systems. The optical measurement systems may include a light generation assembly that is configured to generate light via a light source unit, and a photonic integrated circuit that includes a launch group having a plurality of emitters. Each of these emitters is optically coupled to the light generation assembly to receive light generated from the light generation assembly, and may emit this light from a surface of the photonic integrated circuit. The optical measurement system may perform a measurement in which the light generation assembly generates light and each of the plurality of emitters simultaneously emit light received from the light generation assembly.