The devices of the CamBoard pico family are 3D camera development kits, working based on Time-of-Flight (ToF). Each device consist of VCSEL lasers and a 3D imager.
VCSEL laser is sending out modulated IR light, the reflection of the modulated light is received by the 3D imager. The 3D imager is measuring the phase shift of the modulated light and by this the distance to the target.
The 3D cameras of the CamBoard pico family provide a digital stream of raw data. This data is used for depth calculation on the host system, using SW (Royale SDK).
Output, provided by the Royale SDK:
a. Royale provides a 3D point cloud of x, y, z data, gray value and confidence.
b. The gray image provides an IR image of the amplitudes. The amplitude values represent the amount of the reflected light of the VCSEL laser.
Accuracy is the precision of a distance measurement over several measurement frames.
It is a measure how precise distance is measured e.g. while changing exposure time.
Repeatability is the precision of a frame-by-frame distance measurement.
It is a measure how noisy the distance measurement is
The values in the data sheet includes accuracy and repeatability
The reflectivity coefficient describes the percentage of the light returned from the target.
Targets with high reflectivity can be detected on long distances.
The values in the data sheet are based on a 75% reflection of a Lambertian reflector.
Due to the periodicity of the frequency modulation the unambiguous range for the distance calculation is limited.
The 3D cameras of the pico family provide some flexibility in the unambiguity ranges. It can be modified by the use cases, provided in SW.
In use cases with high frame rates and low range, the unambiguity range is ~2.5 m
In use cases with frame rates up to 25 fps, the unambiguity range is 7.5 m
If not noted differently, the measurement ranges in the data sheets are defined in indoor light conditions with moderate background light.
Outdoor light conditions:
On strong ambient light (e.g. sunlight), some light from the sun will still pass through the optical filter of the camera. In general, the system is quite robust against it due to the patented circuitry (SBI – Suppression of Backgrund Illumination).
a. In bright sunlight, the measurement range of the 3D camera is reduced.
b. In bright sunlight, the noise of the distance measurement increases.
It is recommended to fix a pico flexx with adhesive magnets or to build a 3D printed clamp. A STEP file of the housing can be downloaded here.
Comes with an installation bar which can be attached from rear.
1/4 inch single hole for Tripod mounting.
Front side of the lens.
10 mm behind front side of lens.
pmd ToF technology is very scalable. The pico family Development Kits are external USB modules but for integration into devices usually MIPI modules are used.
Those can become so small that they fit in today´s smartphones. Find out more: https://www.youtube.com/watch?v=I8YFM-Mn4D8
To change the FoV, there are 3 major topics to consider:
a. New lens: a lens with the adjusted Field-of-View FoV needs to be applied.
b. New VCSEL laser: the Field-of-Illumination (FoI) of the VCSEL laser needs to be adjusted to the changed FoV of the lens.
c. Depending on the opening angle, the 3D calibration needs to be modified.
With a change of the FoI, laser safety needs to be re-assessed.
In case of reasonable volumes, we are happy to support. Please feel free to come back to us.
The use cases demands a minimum bandwidth of 140 MBit/s.
The use cases demands a minimum bandwidth of 490 MBit/s.
a. The pico flexx works with USB 2.0 and 3.0.
b. The pico monstar works with USB 3.0.
The 3D cameras of the pico family are based on USB only.
Please come back to us on further questions.
There is a USB–OTG adapter cable supplied with the pico flexx.
Technology Side Effects
Saturation happens when the exposure time is too long. No distance information is generated. The easiest way to avoid is by reducing the exposure time or by using the auto exposure.
In case of low signal (caused by low reflective targets), no distance information is generated. The best way to avoid this is changing the use case to a mode with higher exposure time.
Stray light is light that scatters randomly in the optical lens system. That means that not only the light coming from a specific point in the scene reaches a corresponding pixel on the image sensor, but also a mixture of light reflected from other targets.
Typical scenarios with stray light are high reflective targets close to the camera (e.g. white table). Therefore, the most effective way is to remove stray light causing objects from the environment.
In addition, there is SW filtering to mitigate this effect.
Multi path interference occurs when modulated light scatters around within the scene. In such cases, beside of the direct reflection of the target, some reflections from other targets are mixed into the distance measurement.
Typical scenarios with multi path interference are when high reflecting targets are close to those with low reflection. With measuring on 2 frequencies, this effect can be detected. On Royale, by default the pixel with multi path interference are filtered out.
pmd´s Time-of-Flight technology is very robust against ambient light due to the patented SBI (Suppression of Background Illumination).The SBI is an in-pixel circuitry that subtracts ambient light and therefore prevents the pixels from saturating.
Further improvement of ambient light robustness can be achieved with optical filters (bandpass) and / or coated lenses.
The illumination power plays an important role, so rule of thumb is: the more active illumination is used the more range can be achieved and the more robust the system is against ambient light.
The CamBoard pico family cameras have been optimized for indoor use. They will also work in sunlight but please note that the data will be more noisy or in other words the usable range will decrease.
Changing light source to 940 nm wavelength:
The sunlight spectrum has a dip of amplitude in the range of 940 nm; therefore a performance increase is possible
For 3D cameras of the pico family, interference is minimized based on a technique called SSC.
SSC (Spread Spectrum Clock): permanent shifting of modulation frequencies to minimize the chance that two cams work with the same modulation frequency.
Since the distance image is calculated out of 5 to 9 raw images, distance changes within this measuring time will lead to signal inconsistency.
The best way for mitigation is to shorten the time to capture the raw images. This can be done by reducing the exposure time.
In case there is a need for range and for depth data in parallel, the use cases „mixed mode“ are recommended. There are 2 data streams in parallel. One stream is used for the range and the other one for the fast moving objects.
When a pixel is directly at the corner of an object, the reflected light is a mix of the object and the background distance. As a result, the calculated distance is in the middle between object and background. Flying pixels are detected by Software and filtered out.
The CamBoard pico family DevKits come with pmd´s powerful software suite Royale, containing all the logic to operate the 3D camera. Royale is cross platform compatible and runs on Windows, Linux/ARM, Ubuntu Linux, macOS and Android/ARM.
The package includes a visualization tool, the Royale Viewer.
The SDK to develop your own applications is C++ based and supports also several programming languages and libraries like ROS, OpenCV, OpenNI2, Matlab, C, DotNet.
- 3D point cloud: X, Y and Z values for every pixel result in a point cloud of the observed scene.
- Gray value: In addition to the Z value, every pixel provides a gray value, which represents the signal strength (amplitude) of the active illumination, so this is an IR gray value image. It can be used for standard 2D image processing and it is perfectly aligned to the depth image. It is also not affected by background light so it is a very robust 2D image in every light condition. This data also directly corresponds to the depth data quality so it gives a performance indication for the depth data.
- Confidence value: This value provides information whether the pixel measured a valid 3D value or whether the 3D data is not reliable due to saturation, underexposure or other reasons.
The Royale viewer is a tool to control the camera and to view the 3D and gray values, provided by the Royale API.
With this viewer, different modes and settings can be explored.
In addition, the viewer provides data to export 3D data in the PLY format.
The Royale API to develop your own applications is C++ based and supports also several programming languages and libraries like ROS, Python, OpenCV, OpenNI2, Matlab, C, DotNet.
3D cameras of the CamBoard pico family are supported. The LINUX arm 32-Bit binaries are tested with Raspbian.
Due to computational limitations of the Raspberry Pi, the number of frames per seconds is limited.
In principle, pmd is open licensing software commercially. Details are to be discussed under NDA.
Yes, each measurement frame can be exported to the polygon file format (PLY).
With the Royale v3.19 a Python Wrapper for our pmd ToF depth has been added. It runs on Windows, Linux and under virtual environments as well. To use the Python samples you have to install numpy and matplotlib for the visualization. The Python Wrapper is supported by Python 3.6.X.
Only Python 3.6.5 has been tested.
For further details and several examples please check the README.md file within the Python folder of the Royale download package.
The Python Wrapper for ARM Linux is implemented with Royale 3.21
How to get one?
The pico flexx comes with a USB cable, an USB-OTG cable adapter and a Getting Started Guide. In addition the CamBoard pico flexx comes with pmd´s powerful software suite Royale, containing all the logic to operate the 3D camera including a visualization tool, the Royale Viewer. For more information visit https://pmdtec.com/picofamily/software-download/
The pico monstar comes with a USB cable, a fixation bar and a Getting Started Guide. In addition the CamBoard pico monstar comes with pmd´s powerful software suite Royale, containing all the logic to operate the 3D camera including a visualization tool, the Royale Viewer. For more information visit https://pmdtec.com/picofamily/software-download/
We are closely working together with our distribution partner Automation24. Their experts will process the ordering, payment and shipment of your development kit pico flexx. With their help, we can offer you fast, worldwide shipment as well as many different payment options and a secure state of the art ordering process.
If you have any questions regarding the ordering process, do not hesitate to contact them directly. In case of technical questions visit our FAQ or drop us a line via our contact form.
If you have a special request, technical questions or want to order a larger batch of pico flexx or pico monstar, please don´t hesitate to contact us directly.
Visit the product page of flexx and monstar for further information about the ordering process.
The CamBoard pico flexx and monstar both are Laser Class 1 Devices.