# Tag Info

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A 3D laser range finder or LIDAR such as the one on the Google Car is far more expensive than a camera. The other reason is that while in case of a LIDAR the distance of every pixel is available, the generated data to be processed is enormous. You have to transfer and process data faster which comes out again as rising cost. Finally cameras usually have a ...

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The underlying mechanism used by high performance laser painting devices is usually a galvo (Galvanometer scanner, Laser Galvanometer or Mirror Galvanometer). High performance galvos, like this one from scanlab are essential to the laser micro-machining (drilling, cutting, marking) industries: Their cost and performance may significantly exceed your ...

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In addition to those points in Bence's answer, cameras can: Calculate many complex features that result in very robust matching between frames, and object recognition High angular resolution (typical low->high range goes from $0.5^\circ$ -> $0.025^\circ$) Lower power usage Passive sensor (doesn't require 'clean' signal of a laser)

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navigation in urban environments Depending on the laser, there might be legal constraints on where you can use it. Running around town throwing laser rays around might require special permission/licence.

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If you look in the industry, they usually use capacitive proximity sensors. This sensors can be adjusted easily to sense behind the glass. In addition I can tell you, that this measurement is highly reliable. Usually they start around 70$, but you find also some cheaper DIY-solutions. Another possibility is the use floating styrofoam with a magnet on top ... 3 Yes, there is such a system available today, ScenSor from DecaWave: These tags can measure their distance from base stations using the time of flight of radio packets. They have an precision of about 10cm, I.E. successive samples are randomly distributed in a 10cm diameter cloud around the true location. Also, the radio signal needs a clear line of sight ... 3 I'm pretty sure that a very basic IR proximity sensor would do the trick. Glass is opaque to all but visible light. IR (as well as UV) will not penetrate the glass and you ought to be getting reliable distance measurements to the glass's surface. 2 You could use AR markers attached to each robot or in known locations around the room. In fact, this is how it is typically done in research for indoor, multi-robot systems. The libraries for recognizing and extracting range / angle information from AR markers are well developed, and included in the Robot Operating System. Now, you won't need to actually use ... 2 Another sensor that you should investigate is ultra-short baseline (USBL). I have used the MicronNav with success in the past. You mentioned accelerometers, but what I think you really meant is an inertial navigation system. These fuse data from accelerometers, gyros, compass, and optionally GPS for a more accurate dead-reckoning. I have used the ... 2 One way you can use SLAM in your setup is to stop the robot every 30 cm or so, and perform a sweep with your lidar. You can then use e.g. one of the 2D SLAM packages from openslam. The problem with sweeping while you are moving is that you cannot get any correspondence information from a single range reading. SLAM works by associating features in one ... 2 A well lit, perfectly circular object on a contrasting background, like a puck on an air hockey table, is pretty much the ideal use for webcam object tracking. A classic air hockey table has a light bar/score indicator across the middle of the table - just put the camera in there looking down. Check out the OpenCV library and webcam tracking tutorials ... 2 Like other already answered. Cameras typically are much cheaper than Laser Range Finders. When you talk about camera you mean the 2D cameras isn't it? There are some 3D cameras like the ifm O3D3xx family of cameras available. Those camera may not have the accuracy of a laser scanner but they provide 3D depth data in reasonable frame rates at a price point ... 2 I think you can divide your problem into two subproblems: 1) Partition your 2D scan into segments/clusters which represent single objects. A basic algorithm could be: Start at first laser reading and create a new cluster Add next reading (neighbor) to cluster, if the range difference is below a threshold Else create a new cluster This approach can be ... 2 Unless you need very good resolution or a very tight detection pattern, I would go with an ultrasonic sensor. They can be very cheap and easily meet your detection range specs, for the very low end look at something like the HC-SR04, and for more serious applications Maxbotix offers a wide range of sensors. 2 You are correct. Most Velodyne LIDARs (very commonly used on autonomous vehicles), use 905 nm diode lasers, and so do many Hokuyo laser scanners and SICK LIDARs. A new company, Ouster, uses 850 nm lasers, claiming that their choice of lower wavelength is because the "atmospheric water absorption is orders of magnitude lower than at 905nm". Some more info: ... 2 Both 1550nm and 900nm ranges are used in different lidars. Velodyne and majority others use 905nm lasers because these diodes are really cheap. 1550nm are used when there is a need for very long distance measurement range, such as Luminar, as the eye safety threshould is several orders of magnitude higher for this wavelength than 905nm. In principle, ... 2 The most traditional method is to keep looking at the trajectory and see if your current location is close enough to the previously visited place. Once this happens run the ICP. If ICP converged normally, that is your loop closure. A bit more advanced method is doing a place recognition. Generate a keyframe every few meters and extract a feature descriptor ... 1 If you are willing to work at it, adding LIDAR to the Create 2 should be possible. If you read the iRobot Create 2 OI Specs, you will see that you can communicate with the Create via serial communication. If you look at the datasheet for the RPLidar, you will see that you can communicate with the sensor using serial communication. Because you cannot program ... 1 Is it possible to detect road surface (not grass) using LRF data or other laser sensors? Yes it is possible. A laser scanner will give distance measurements along a scan line. Presumably, the road surface is sufficiently smooth that it will be distinguishable from natural terrain. A quick way (certainly not the best way) to get this working for a prototype ... 1 I don't think people really "want" to use only cameras. If every researcher could afford the LiDARs they'd all put LiDARs on they robots for outdoor environment. Cameras are pretty cheap and the only limit to range is the pixel/superpixel resolution that you can process in your algorithm/software. Most researchers (including me) use structured light ... 1 Are there any advantages to using a LIDAR for SLAM vs a standard RGB camera? You may check this link where I have previously answered a somewhat similar question. (advantages and disadvantages of each) in urban environments If you are referring to autonomous cars like the Google ones, there are lots of considerations and constraints (safety, cost etc.). ... 1 Check this, starting from the last part: I think they are using the same technology as the several of their sensors: ( the one you mentioned) In the 100 dollar price range I think you will not find anything that meets your demands. I have no experience with golf laser range finders. 1 I think 0.3m noise is a bit exaggerated for a scanning laser rangefinder. As you saw with the Hokuyo (which is one of the cheapest LIDARs you can get) they say that it is 0.03m range "error" (they do not explicitly state this is 2$\sigma$, but I have tested the noise profile myself and it is consistent with 2$\sigma\$). My experience with laser scanners is ...

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Am I exaggerating with these values? No your're not but you need to filter the measurements. Also, you can double check datasheet of any laser sensor for the specifications. I've written a code for Kalman filter long time ago for a laser sensor that measures a static point located at <10,10>. Let's see how the filter is working with the noise you've ...

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A digital camera, even on a cell phone will pick up the IR light. A darkened room will help it to show more prominently. No sense in buying any crazy equipment when the phone in your pocket will probably do what you want.

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In addition to Chuck's answer: I recommend using opencv or any other Computer Vision library. But you do not need to go the simple way. Do not place the camera directly above the table. You can place it everywhere you want, in any orientation you want. Because you do know your table, the cameras position and its attitude, you can use some easy ...

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Anything's possible in the world of fabrication and computers, the question is how much time, effort, and money it will cost you. If you haven't built a 3D printer from scratch before, then it might not be a good idea to attempt this; you would have no way to tell whether any problems you experience would be caused by your own design or the existing laser ...

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So this is really a hard task. Estimating the position of a AUV is still a large challenge even in research. There are sensors like as DVL (Doppler Velocity Log) available that can estimate the speed over ground. These sensors working okay, but they only estimating the speed. These devices are precise enough for your use case BUT these devices are to large ...

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The two questions are quite unrelated so it would be best to ask two questions. Otherwise responds will probably fall short on one of them. About Q1: I understand that you are looking at using a servo (RC controlled?) to shift the laser boresight so the laser will shoot a bit up-down or left-right when commanded and, when not commanded, it will shoot normal,...

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I had a look at the protocol specification, which is very well documented and easy to implement. Instead of using the sicktoolbox, I suggest writing your own driver, which meets your recommendations. This gives you more control over the performance, because you can just ignore (for you) useless commands.

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