Triggering is a complex topic and has been previously covered in an Advanced Imaging article. With multiple triggers available for our CMOS camera families we appreciate the need for faster acquisition rates with variable exposures, especially for multi-channel live cell imaging where different fluorophores have different signal levels. Typical multi-channel imaging can be slow due to the need to change filters and manually enter settings, we at Teledyne Photometrics make the most of multiple triggering to make life easier.
Sequenced Multiple Acquisition Real-Time Streaming, or SMART Streaming, allows for continuous imaging while cycling through up to 16 pre-programmed exposure time values. This results in very high frame rate imaging while maintaining the correct exposure level for each fluorophore, and results in highly efficient multichannel imaging.
Our Prime and Kinetix families of CMOS cameras have four independent trigger output signals. This enables the camera to have hardware control over light sources that cycle through different excitation wavelengths during acquisition, such as a multi-wavelength LED light source that rapidly switch between different colors to excite different fluorophores.
The enabled outputs are cycled within each frame. For example, if two outputs are enabled, the output trigger signal alternates between outputs 1 and 2. If all four outputs are enabled, the sequence would look similar to Fig.1.
However, these all have the same exposure time. Not all fluorophores or biological samples are created equal, and additional steps are needed to enable variable exposure levels for each trigger, to best suit each fluorophore while still rapidly cycling between each channel for high-speed multi-channel imaging across a wide range of wavelengths. We do this with SMART Streaming.
Sequenced Multiple Acquisition Real-Time Streaming, or SMART Streaming, is an exclusive Teledyne Photometrics camera feature that enables our cameras to capture a continuous sequence of images while cycling through a maximum of 16 pre-programmed exposure time values. This results in very high frame rate imaging while maintaining the correct exposure level for each fluorophore.
The maximum exposure time per frame is 10 seconds, in keeping with SMART Streaming’s high frame rate benefits. By combining Multiple Output Triggers with SMART Streaming, it is possible to control the exposure time of each output independently, as seen from Fig.2. This is much faster than using software-based methods to control the timing of illumination devices, and results in high-throughput multicolor imaging, suitable when working with high-speed dynamic live cell samples.
SMART Streaming is another step we take at Teledyne Photometrics to remove issues and pains from imaging, using our pre-existing hardware trigger expose-out controls to allow for rapidly switching variable exposure times for different fluorophore wavelengths. With SMART Streaming, software delays are eliminated and multicolor images are easily obtained automatically, with fine control over individual fluorophore exposure still enabled.