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Schlieren Imaging

Image of blast waves in schlieren setup

Schlieren Imaging is a way to make invisible flow elements, such as gases, air, and other transparent media visible.  The recent advancements of in high-speed imaging technology have increased the quality of images possible through this technique. Increased light sensitivity, higher speed capabilities, and specialized features have contributed to the use of this method in a variety of applications.

For a more in-depth look at Phantom cameras in schlieren imaging download our free whitepaper, “High-Speed Imaging Uncovers the Invisible with Schlieren Imaging.”

Why High-Speed Imaging for Schlieren Imaging?

Visible Details

Using a high-speed camera in schlieren imaging, allows researchers to analyze and obtain detailed images of invisible occurrences. Phantom cameras have specially designed CMOS sensors capable of varying frame rates, resolutions and exposure times. The ability to control these settings allows a researcher to be very specific when planning the experiment. Select Phantom cameras come with on-camera data storage options which allow for extended record times. These data management options reduce the amount of downtime between experiments, while data is transferred, and maximizes laboratory use time.

Data Quality

Data is perhaps the single most important aspect of Schlieren as it is the reason the elaborate mirror system is constructed in the first place. Certain Phantom cameras can help ensure that data quality is intact is by providing operators with the ability to temporarily deactivate the camera’s cooling fans. This aids in preventing the heat produced by the camera’s sensor from entering the schlieren field and keep it from destroying data integrity.

Consistency is also important when gathering data quality. As small temperature or air quality adjustments occur in the environment around a Schlieren system the data gathered can change. Large and easy data management features found in Phantom cameras allow for the quick repetition of multiple high-speed events to help eliminate environmental changes that can be difficult to control.

Improved Light Sensitivity

Schlieren imaging is the visualization of a fast process with a very small light source. This means that sensitivity is key to obtain a proper image. Since schlieren imaging is a naturally high-contrast occurrence the ability to manipulate tonal curves takes presence over the need for high dynamic range. By adjusting tonal curve a researcher is able to control the grey-levels and extract the most detailed images possible.

While it is possible to utilize both monochromatic and color sensors for Schlieren imaging the mono sensor will be more light sensitive.  When picking a Phantom camera the sensor choice should take into consideration what type of data needs to be collected and which sensor will be able to deliver that.

image of v2512
UHS v2512

The Phantom v2512 utilizes a large 1 Mpx sensor with built-in features that enhance upon the already high-sensitivity capabilities. In low-light situations visibility is key and with schlieren imaging the large pixels allow for the most detail possible at ultra-high frame rates.

VEO 1310
VEO 1310

The Phantom VEO 1310 captures over 13Gpx/second and includes a binned mode for increased frame rates at reduced resolutions. The sensitivity, low noise and frame rates are excellent for capturing shockwaves and turbulent airflow. 

image of VEO 710
VEO 710S

The Phantom VEO 710S is perfect for schlieren applications that occur outside of a laboratory. The compact and ruggedized body increases ease of setup and ensures any captured data is kept safe from outside elements. 

image of VEO4k 990
VEO4K 990S

The VEO4K 990S brings 4K resolution to schlieren imaging. The high-resolution images allow researchers to obtain more exact measurements by increasing visible detail.