Basler ToF Camera – Frequently Asked Questions (FAQ)
On this page you’ll find answers to some of the most common technical questions concerning the Basler ToF Camera.
1. What is Time of Flight?
Time of Flight is a method for distance measurement. The time it takes for light to travel from the light source to the object then return to the sensor is measured and calculated into a distance.
2. How accurate is the measurement of the Basler ToF camera?
The resolution of the Basler ToF camera along the Z axis is precise to +/- 1cm. The user’s manual contains a graphic with detailed accuracy measurement data.
3. What resolution does the Basler ToF camera offer?
The Basler ToF camera offers a resolution of 640 pixels (horizontal) x 480 pixels (vertical).
4. Which sensor is used in the Basler ToF camera?
The Basler ToF camera uses a ToF specific VGA mono sensor from Panasonic.
a. Are other sensors planned?
Yes, the plans for the overall product life cycle calls for other models, including ones with color and 1.3 MP resolution in mono and color versions. For more information about the overall development plan, please talk to your contact in the Sales department.
5. Which applications are suitable for the Basler ToF camera?
The Basler ToF camera can be used in a variety of applications in the fields of logistics, factory automation, robotics and medicine.
6. Why did Basler choose to use the Pulsed Time-of-Flight method and how does it differ from other potential methods?
One alternative method for example is called Continuous Wave Time-of-Flight. It is based on measurements of the phase length for a brightness-modulated light source. The method is mature and works with standard electronics. Yet these sensors are relatively large and just offer resolutions lower than VGA.
Pulsed Time-of-Flight measures distances based on the travel time for many individual pulses of light. Due to technical progress the creation of accurate light pulses, and their exact measurement with high resolution has become economic, thus this technology will rapidly evolve.
7. What is the framerate for the Basler ToF camera?
The current model of the Basler ToF camera runs at 20 fps in free run.
a. Can I improve on that speed or does it already represent the sensor's limit?
The sensor's limit is 30 fps. If you want to achieve that speed with a Basler ToF camera, however, you'll need a good cooling system. Contact us if you're interested in this.
8. Can I improve the accuracy by using a sensor with higher resolution?
Not the accuracy in Z-axis. That will remain at +/- 1cm. However, the X and Y axis resolution can be improved, which leads to a higher accuracy throughout the system.
9. Can I improve the accuracy of my ToF camera by recording and calculating multiple images?
The camera already includes a local and a temporal filter for precisely this purpose. They can be parameterized to meet the requirements of the application.
10. How does the operating temperature affect the accuracy of the Basler ToF camera?
The camera is factory-calibrated in an ambient temperature of 22°C, and that is where it performs most accurate. The measurement values deviate by a few millimeters for each °C. After a cold start, the camera requires 20 minutes to achieve thermal stability. You will find more detailed measurement data in the ToF User Manual.
11. Is there internal temperature compensation?
No, the current product does not offer this. The camera is equipped with two temperature sensors that can be read out via the API.
12. Can I buy the Basler ToF camera with another lens?
No, the current Basler ToF camera is only sold with a 57°x43° aperture angle. Further models are in planning. Please get in contact with your sales rep.
13. Can I buy the Basler ToF camera without a lens and use my own lens?
We are currently working on a recipe to make this possible. By the end of 2016 it should be possible to change the lens by yourself and recalibrate the cameras by yourself.
14. Is the Basler ToF camera pre-calibrated to ensure maximum accuracy?
Yes, each individual camera is pre-calibrated to each peak performance.
15. What kind of light source is used in the Basler ToF camera?
The Basler ToF camera uses 8 LEDs as its light source.
16. What is the wavelength spectrum for the Basler ToF camera?
The Basler ToF camera works with a wavelength spectrum of 850nm.
17. How long are the pulses emitted by the Basler ToF camera?
The pulse length for each pulse totals 40 ns.
18. What is the output of the light source for the Basler ToF camera?
8W (1W / LED)
The LEDs have a 30% efficiency ratio. This represents an optical light output of approx. 3W (0.4W / LED).
19. Can I use the Basler ToF camera for outdoor applications as well?
The current Basler ToF model is optimized for inside use and encounters difficulties with strong sunlight and more generally with very intensive light sources in the near-infrared range (850nm). In this case the measurements will become imprecise. We are however working on a ToF model for outdoor use.
20. Many portions of my image are very dark or very dark red, with noise artifacts.
a. What is causing this?
i. If the reflection from a surface is either too strong (saturation) or tooweak, then the distance cannot be calculated properly and is becoming black. The "Confidence Threshold" parameter can be used to influence this behavior.
ii. Pixels that capture both the foreground and background deliver false distance values, namely halfway between those surfaces. They are filtered out as outliers and become black. The "Outlier Threshold" parameter can be used to influence how they are handled.
iii. Red and noisy sections result from disruptive signals. This can be caused by interferences from a second camera or strong stray light. No reflecting surfaces should be positioned in the vicinity of the camera. These will lead to stray light, which overwhelms the actual signal from weakly reflective objects.
b. How can I prevent this?
i. Adjust the exposure time
ii. Avoid stray light
iii. Vary the distance and the position of the camera
iv. Adjust the confidence threshold
v. Adjust the outlier tolerance
vi. Use the HDR feature
21. What is the protection class rating for the Basler ToF camera?
The current model is rated to protection class IP30.
a. Are there other models with other protection class ratings?
There are no models at present rated to a higher protection class, but we're working on it.
22. I'd like to use the camera in an outdoor setting and want to put it into a housing. What factors require special consideration? Or can I simply put the ToF camera into a standard protection housing?
Cooling is a primary consideration before mounting into a protective housing, as is avoidance of stray light (no reflecting housing parts near the lens).
The protective glass must not cause reflections. Ideally the lens and the LEDs will have separate protective glasses.
23. I'd like to use multiple Basler ToF cameras in my application.
a. Can this cause problems?
Yes, the light pulses from an addition ToF camera cause errors. We implemented a multichannel feature where you can use four different channels. This makes the usage of up to four cameras possible. A software and hardware trigger are also implemented to solve the issue.
b. What is the best way to set up a multi-camera configuration?
Use the trigger or the multichannel feature.
24. To date I've triggered my 2D cameras externally to ensure the desired synchronization and control of when the camera captures an image. Can't I trigger the Basler ToF camera in this way as well?
A software and hardware trigger is available and can be used same way like with your 2D camera.
25. Can I use a 2D and a 3D Basler ToF camera within one system?
Yes, you can install the ToF driver and the pylon SDK on one computer.
26. How can I configure and modify image formats for confidence, intensity and range map?
Each time it captures an image, the camera delivers a multipart image that contains multiple images, such as a point cloud and an intensity profile. The parameters Image Component Selector, Component Enable and Pixel Format allow you to define which images are in a container.
27. From a pure performance standpoint, the Kinect camera is also well suited for my applications and is cheaper as well. What benefits does the Basler ToF camera offer compared with the Kinect 2.0 from Microsoft?
Unlike Microsoft's Kinect, which is a mass market consumer product, the Basler ToF camera is intended for industrial use and industrial customers. This means it will be available for a much longer period and has been designed for robustness and stability. Its lifecycle will also be managed with industrial customers in mind, including timely announcements before phase-out and last time buy deadlines. Consumer products such as the Kinect by contrast sometimes disappear overnight, without any promise of a successor product.
28. I have to download a GenTL Producer compliant with the GenICam standard to operate the Basler ToF camera. What exactly is that standard and why does Basler use this process?
GenTL is the third module of GenICam. While GenApi and SFNC are more oriented toward the camera's settings, GenTL regulates the transport of the image data. GenTL is the latest module.