Study of active millimeter-wave image speckle reduction by Hadamard phase pattern illumination

Area of Science:

• Physics
• Optical Engineering
• Signal Processing

Background:

• Active millimeter-wave (MMW) imaging systems often suffer from inherent speckle noise.
• This noise arises from the coherent nature of artificial MMW sources, degrading image quality.
• Speckle noise reduction is crucial for enhancing the utility of MMW imaging.

Purpose of the Study:

• To investigate the applicability and effectiveness of the Hadamard speckle contrast reduction (SCR) technique in MMW imaging.
• To analyze the influence of various parameters, such as Hadamard pattern order, size, and resolution, on SCR performance.
• To identify practical implementation challenges and their impact on speckle reduction efficiency in MMW systems.

Main Methods:

• Adapting the Hadamard SCR technique, previously successful in laser projection, for MMW imaging applications.
• Systematically evaluating the impact of Hadamard pattern parameters (order, size) on speckle reduction.
• Assessing the influence of image and pattern resolution on the efficiency of speckle reduction.
• Considering practical limitations associated with implementing Hadamard patterns in MMW hardware.

Main Results:

• Hadamard SCR demonstrates potential for reducing speckle noise in active MMW images.
• Speckle reduction efficiency is significantly affected by Hadamard pattern order and size.
• Image and pattern resolution play a critical role in the overall effectiveness of the SCR technique.
• Practical implementation constraints can limit the achievable speckle reduction.

Conclusions:

• The Hadamard SCR technique is a viable method for mitigating speckle noise in millimeter-wave imaging.
• Optimizing Hadamard pattern parameters and considering resolution are key for maximizing speckle reduction.
• Understanding and addressing practical implementation challenges is essential for successful deployment of SCR in MMW systems.