Lidar is an emerging standard when it comes to full-journey people measurement. It provides great coverage, environmental flexibility, absolute privacy protection, and remarkably detailed measurement. But when it comes to a real-world people-measurement implementation, it’s not as simple as just choosing lidar, because there isn’t just one kind of lidar. Even if you’ve decided on lidar as your people-measurement technology, you need to decide what type of lidar is right for your space and application.

There are three basic types of lidar: mechanical puck, mechanical dome and solid state. Regardless of the type of lidar you pick, you’ll get the same basic lidar characteristics: how the system is architected, its real-time capabilities, its privacy advantages, and its general deployment strategies. What changes between lidar types are primarily the beam patterns that define the shape and size of each sensor’s coverage area.

Puck sensors deliver a full 360-degree view of a scene – meaning that the lidar rotates and, as it spins, tracks a complete circle around the side of the sensor. This type of lidar has the best overall coverage, but it will have a blind spot beneath it. That means that even if a single lidar should provide coverage for a space, two may be necessary to eliminate blind spots.

Mechanical dome lidar sensors solve this problem by rotating the beams directly beneath the sensor – which is mounted in the ceiling very much like a stereoscopic measurement camera. Dome lidar sensors are ideal for use-cases where you need to cover smaller spaces and want to deploy a single lidar. In many respects, dome lidars function like stereoscopic people-measurement cameras.

Solid-state devices provide more limited fields of view. They’re typically side-mounted on walls – angled (physically or simply in terms of beam pattern) to look down on a space. Solid-state sensors may have more limited fields of view, but they can be less expensive and, of course, solid-state devices have extraordinary field reliability.

Here’s a look at the typical beam patterns for each type:

The mechanical lidar will nearly always give you the most coverage for your dollar and it’s the most common choice for people-measurement applications. But if you’re measuring a space that can be covered with a single lidar, then a dome lidar without a blind spot might be a better choice. Solid-state is best in situations where you can’t mount a sensor in the ceiling or high on a wall. You’ll sometimes run into this situation when you need to measure a single display that is being deployed in an environment where you can’t pull cable.

Some lidar manufacturers provide a full-range of devices and have puck, dome, and solid-state devices in their product line. Others specialize in a single type. That means you’ll sometimes have to make at least a partial decision about type of sensor before you choose a manufacturer much less a specific model. There are implementations where any of the three types will work, but if you’re space lends itself to one kind or another, it’s best to know that before you start trying to fit a square lidar into a round space!