Aug 15, 2022
OAK-D Pro vs. Intel RealSense D435iAll kinds of active stereo power
We take a lot of pride in offering the best robotic vision solutions in the world. Even competitors with bigger names–at least for now–like Intel, are in for a surprise. When like-in-kind options are set side by side, the choice (and the picture) is clear.
Going ProFor some background to start, let’s unpack two core functionalities featured by the Luxonis OAK-D Pro: its IR laser dot projector and IR illumination LED. The IR laser dot projector sends out a stream of small dots in front of the device, which is done to assist with disparity matching, and is especially helpful for surfaces that have low visual interest, for example, a blank wall or a sheet of paper. Basically, any objects that have minimal color distinction and/or little to no texture. To best visualize these kinds of surfaces we use a technique called Active Stereo Vision (ASV). ASV happens on-device in the same way that passive stereo depth happens on devices without IR laser dot projection, such as the OAK-D-Lite.
Meanwhile, the night-vision functionality brought to the table by the IR illumination LED is nice and easy: it allows for on-device artificial intelligence (AI) and computer vision (CV) processes to run in low or zero light conditions. Tasks like object detection, image training, and semantic segmentation are all much more manageable in low light when supplemented with the IR illumination LED. Here we see an example with night-vision turned off next to an example with night-vision turned on. It’s night and day.
Calling All CompetitionNow, let’s dig in and compare some examples of performance between the Luxonis OAK-D Pro and the Intel RealSense D435i. While LED illumination is a game changer when needed, it’s more straightforward, so we’re going to zero in exclusively on the active stereo comparison here. We’ll look at two scenarios, the first with the laser dot projector disabled, and the second with it enabled, to show the full range of excellence of the OAK-D Pro. First, here’s our target image (provided to us unsolicited by a customer, who was doing their own independent testing).
We see two primary surfaces that have low visual interest: the table and the wall. Their nearly identical colors and textures can present a tricky challenge when it comes to sensing depth. We also see a wire and a tape dispenser, which offer minimal texture clues as well. Now, here’s what the image looks like through both the RealSense D435i (on left) and the OAK-D Pro (on right). Remember, we’re first seeing things with the laser dot projector turned off.
The best choice is clear. On the left, the central figure of the box stands out, but it’s sitting in a scattering of noise. The other two primary objects, the wire and the tape dispenser, are both washed out and difficult at best to realize they exist at all. On the right, the box is clear as well, however the low visual interest surfaces are better defined. The shape of the wire is also much more prominent, both in the curved section behind the box and the closer straight red section in front. And, while the outline of the tape dispenser is slightly warped, its full shape is captured. And again, this is the image with the OAK-D Pro IR laser dot projector turned off, which means we have lots of room for improvement. Let’s take a look at how things change when it’s activated.
As would be expected, both devices improve a lot here. However, on the left with the RealSense D435i, while we see the scene more clearly, the depth readings of our low visual interest surfaces are still inconsistent and definition around the edges is lacking as well. On the right, the OAK-D Pro captures a much more holistic scene, and the IR laser dot projector helps it to measure the depth of the low visual interest surfaces consistently and accurately. We also see more consistency in both the wire and tape dispenser. There it is, the seven-year-old in all of us was right: lasers make everything better. If you’re working with low visual interest surfaces and need on-board active stereo, while we see some similarities between the OAK-D Pro and the RealSense D435i, go with Luxonis. And the OAK-D Pro doesn’t stop there. In other areas it just completely laps the field. Whether it’s AI, CV, encoding, or more, the OAK-D Pro is the robotic vision solution you need.
Stuart MooreCommunications Director