Multimode illumination for speckle reduction and angle neutrality in millimeter wave active imaging: range and...

Area of Science:

• Optics and Photonics
• Wave Physics
• Imaging Science

Background:

• Active illumination offers advantages in millimeter and submillimeter wave imaging, including signal margin and range determination.
• Challenges include speckle noise from diffuse targets and angular alignment needs for specular targets.
• Previous work utilized spatially time-resolved modulated multimode mixing to address these limitations.

Purpose of the Study:

• To extend previous findings by demonstrating range resolved multimode mixing for active imaging.
• To provide statistically independent images for effective speckle reduction averaging.
• To explore systematic illumination of spatial modes in a "grassy field" geometry.

Main Methods:

• Utilized range resolved multimode mixing for active illumination imaging.
• Employed systematic illumination of spatial modes.
• Generated statistically independent images for averaging.

Main Results:

• Demonstrated range resolved multimode mixing as a viable alternative for active imaging.
• Achieved speckle reduction through averaging of statistically independent images.
• Successfully implemented "grassy field" geometry for spatial mode illumination.

Conclusions:

• Range resolved multimode mixing effectively mitigates speckle and alignment issues in active illumination imaging.
• The method provides statistically independent images crucial for speckle reduction.
• This approach enhances the utility of active imaging for diffuse and specular targets.