Discover the differences between Flash LiDAR and Scanning LiDAR in their illumination methods and how they capture scenes.
Flash LiDAR and Scanning LiDAR differ based on how they illuminate a scene.
Flash LiDAR uses a detector array to capture a wide-angle view in a single pulse. The illuminated area is as large as the detector array, and the laser beam must be wider to cover the array.
In contrast, Scanning LiDAR uses a narrower laser beam and scans across the scene sequentially.
The angular width of the laser beam is subject to the diffraction limit, which defines the smallest possible beam divergence. This limit is expressed by the formula:
where D is the diameter of the transmit aperture, and λ is the wavelength.
LiDAR systems often use Gaussian beams, but super-Gaussian beams are sometimes preferred for better uniformity in illumination. A Gaussian beam focuses more energy in the center of the point spread function (PSF), while a super-Gaussian or flat-top beam distributes energy more evenly, reducing clipping by the aperture.
For a Gaussian beam, the intensity distribution is defined by the following equation:
where a is the magnitude, b is the offset, c is the width, and N is the beam order.
In Flash LiDAR, this broad illumination enables simultaneous detection by multiple pixels, allowing rapid imaging. Figure below shows how a Flash LiDAR system illuminates an area in one pulse.
