HERA – compact and robust hyperspectral camera
The innovative hyperspectral camera HERA offers for the first time the possibility to create a real hyperspectral image in “snapshot” mode, just like with a conventional RGB camera. At the same time, extremely good spectral and spatial resolutions and a very high sensitivity over the detected VIS/NIR wavelength range are achieved.
It couldn’t be more simple: the compact plug-and-play camera HERA is placed in front of the object and the imaging is done as with a normal RGB camera – after setting the focus and exposure time, all that has to be done is to start the recording. In contrast, in conventional hyperspectral imaging, the camera or the object often has to be moved to record the spectra of the individual pixels of the object line by line in order to obtain a complete hyperspectral image in the end.
At the same time, the underlying technology of the HERA camera makes it possible to set the spectral resolution to any level within the specifications, and thereby finding the perfect balance between spectral resolution and measurement time. The spatial resolution is excellent, as every pixel of the detector is available for spatial recording.
Since slit and gratings are not required, a particularly high sensitivity is achieved and even low-light applications such as the spatial recording of fluorescence spectra become possible.
Therefore, HERA is the perfect solution for objects that move slowly or not at all. Hyperspectral images could not be obtained easier or better.
- Snapshot operation
- Wide wavelength range from 400-1000 nm; optional: 950-1700 nm
- Very high spectral and spatial resolution
- Outstanding sensitivity enables even low-light applications
- Compact and robust plug-and-play camera
For HERA, the usual Fourier transform spectroscopy is transferred to a hyperspectral camera. Thereby, an interferogram in each pixel is recorded, which is converted into the spectrum of the incident light by Fourier transformation.
The unique feature of HERA is the novel interferometer that NIREOS has developed and also sells under the name GEMINI. This common-path interferometer, which is based on the movement of two birefringent wedges against each other, achieves a stability in delay of better than one attosecond.
Functionality of Fourier transform spectroscopy
The advantages of this technology are obvious: since the spectral resolution of the HERA camera depends on the possible variation range of the phase difference between the two beam replicas, the spectral resolution can be freely selected up to a maximum. The maximal travel range of the birefringent wedges in relation to each other determines the highest possible spectral resolution. In each pixel you get a continuous spectrum with the requested number of spectral bands.
As mentioned above, gratings and slits are not required, so that the light throughput is significantly improved and the HERA camera is also perfectly suited for low-light applications.
In addition, there is no need for filters in front of the different pixels, as used in some other (multispectral) snapshot cameras. This means that every pixel of the detector is used for spatial recording, there is no loss of resolution and no pixel-related spatial allocation errors.
|Spectral range||400 - 1000 nm|
|Sensor spatial resolution||1280 x 1024 pixels|
|User adjustable spectral resolution||<1.5 nm @ 400 nm
<10 nm @ 1000 nm
|Number of bits||12 bits|
|Software interface||Labview based interface|
|Number of spectral bands||∞*|
|Field of view||16 degrees|
|Working distance||250 mm - ∞|
|Dimensions||205 x 150 x 83.5 mm|
*HERA is FT spectroscopy based instrument and number of spectral bands is software selectable and independent from measurement time.