Please note: One of the new key features – Volumetric Calibration Refinement – is not highlighted in this news story as more detailed, in-depth information will follow separately. The same applies to the range of new cameras supported with this release.
New features implemented
Imaging Setup Assistant (ISA)
The new Imaging Setup Assistant guides the user in setting-up a single or multi-camera imaging system by 3D-visualization of the camera(s) position, the test-section (dimensions, window position, and medium refractive-index) and overlapping field-of-view (FoV). Starting-out from one of several predefined setups (e.g. a Stereo-PIV setup for measurements in air or water) a customized setup can quickly be designed and visually inspected. By selecting camera and lens type from the device library, correct parameters such as sensor resolution and size, pixel-pitch and e.g. lens focal-length are automatically used in the simulation of the optical system. In a multi-camera imaging setup the resulting FoV and depth of field are vital parameters for successful calibrations and measurements – additional parameters are easily optimized using ISA.
Imaging Setup Assistant
For PIV the camera positioning, lens settings (aperture) and light-sheet height and thickness can be optimized based on calculated and visualized output from the Imaging Setup Assistant (FoV, magnification, depth of field). By inserting additional information on estimated in-plane and out-of-plane velocities, desired independent vector spacing (interrogation area size) and the seeding used – the Imaging Setup Assistant helps the user to select the optimal PIV parameters. For a specific setup and flow-field measurement, recommended time-between laser pulses (Delta t), light-sheet thickness, seeding particle size and ideal lens aperture can be directly investigated within the Imaging Setup Assistant.
2D Particle Tracking Velocimetry (2DPTV)
With the improvements implemented in the two-frame, two-dimensional Particle Tracking Velocimetry (2DPTV) algorithm you can now achieve high accuracy velocity measurements in double-frame images with moderate to high particle densities, typical to PIV raw images. The 2DPTV analysis is applied after an “Adaptive PIV” analysis in situations with a single Adaptive PIV vector map – or an ensemble of Adaptive PIV vector maps. Useful metrics are also provided together with the results:
- Number of particles detected in frame 1 and 2
- Number of matches found in the 1st pass
- Additional number of matches found in the 2nd pass
- Total number of matches found after both passes
- Match ratios after the 1st and 2nd passes
PIV (left) and PTV (right) results of a vortex ring calculated using synthetic particles indicate that the PTV results are more accurate and have more resolution than the PIV results since they operate on individual particles instead of a collection of particles.
2D Particle Tracking Veloimetry (2DPTV)
In many measurements like simultaneous LIF measurement for multi combustion species, simultaneous PIV/LIF measurement, and LIEF measurements, more than one camera share the same field of view. The Linked Ensembles feature is made to link all images acquired by different cameras for the same measurement. As a result, whenever the user apply any standard view operation (zoom in/out, select of view area, etc.), the same operation will also be automatically applied to other linked images. The process results from linked images are also linked to make the view of the results much more convenient.
Linked Ensembles can link the two images acquired with DualScope, even during preview / acquisition mode. This way the user can easily compare the two acquired images.
Link ensembles with Dualscope
New UI enhancements
Manual Calibration is a new feature under Multi Camera Calibration. It allows for any type of non-standard target to be used for the calibration, not limiting the user to only using conventional targets. This is very useful in locations where isn’t possible to place a conventional calibration target in the field-of-view (inside combustion engine, tight flow channel, etc.), or where data has been acquired using a non-Dantec Dynamics system.
The user can manually overlay the marker grid on the target image by using the mouse to move the corner markers to the desired position. If the calibration image is an image of a physical grid of any type, the user can move the markers so that the grid matches the physical grid in the image. Defining any marker on the grid to be the reference marker (grid reference point in physical space), is also easily done by a single mouse click.
The resulting calibration can be used to de-warp the images, to e.g. straighten out the coordinate system in a distorted image view or to match the coordinate systems in different data sets acquired by different camera types, for facilitating overlap of the different result such as PIV-LIF combined data.
Manual camera calibration
Intensity profile of reconstructed volume
Setting the depth of a reconstructed volume depends on the exact position of the illuminated volume. But how can one know this, or properly check the overlap? In DynamicStudio this can now be checked easily based on a volumetric reconstruction. The added intensity of each plane in z-direction is displayed within an extra graph. When reconstructing the volume in z-direction large enough that the illuminated volume is completely covered, right click in the visualized voxel space and select “Z-Plane intensity” (also applicable on old reconstructions). The following image displays the advantage. Besides the area where the Z-intensities are high, they also have a low level generated by ghost particles, with the rising and dropping of the signal determining the Light sheet positions is easy. If you need to have the numerical values of this simply right click the mouse into the graph and select “Copy data” or directly copy the entire graph.
Intensity profile of reconstructed volume
Show boundaries for Volumetric Reconstructions
Defining the volume for a volumetric reconstruction can be difficult. DynamicStudio now provides more guidance for this setting. In the Volumetric Reconstruction Tab, as well as for the Volumetric Calibration Refinement, a projection of the volume can be displayed. It allows to inspect the involved areas involved in the reconstruction of each individual image and highlights it by a bounding box. This indicates the used area needed for the reconstruction of each camera. Simply use the Show projection button in the reconstruction menus and the pop-up will open. When the green box reaches the limits of the image, or even extends past it, some of these areas cannot be reconstructed.
Volumetric calibration refinement
New feature improvements
10 times faster SMART reconstructions by GPU processing
In order to speed up the calculation of volumetric reconstructions GPUs (Graphics Processing Unit) can be used more efficiently than CPU´s for this task as they offer a large amount of computation power. By implementing the SMART Reconstruction on the GPU, it is now possible to speed up the process dramatically, especially for very large volumes. Compared to previous versions an improvement of up to 10 times has been achieved
New hardware supported
Evergreen High Power laser
The Evergreen HP LRR (High Power, Low Repetition Rate) PIV lasers are now fully supported by DynamicStudio. These high power lasers are ideal for PIV applications e.g. requiring a large field-of-view, or whenever high pulse energies are needed. The laser heads are sealed making them suitable for operation in a wide variety of environments. Because of the sealed laser head design, the lasers are pre-aligned, and no realignment is required. The Evergreen HP LRR PIV laser comes in two models as 340 mJ @ 532 nm, 15 Hz – and 300 mJ @ 532 nm, 30 Hz, respectively.
Evergreen high power lasers