WHY ARE SPECIM CAMERAS LINE SCAN PUSH BROOM CAMERAS?
A line scan camera is based on a matrix detector and an imaging spectrograph. The incoming light passes through a high-performance fore optics and entrance slit, which creates the line imaging configuration of the camera. The line of light is dispersed by the spectrograph into a spectrum and detected by the matrix detector. As a result, one axis of the detector registers position from the line, and the other axis registers the spectral information in each spatial position in the line. This design offers considerable advantages:
- The full spectrum for each spatial position is measured simultaneously, making the measurement insensitive to the movement of the sample or the camera itself.
- Illumination is needed only for the narrow line, and much higher intensity can be obtained with lower total power than in 2D imaging configurations.
- Compared to filter based cameras, the imaging spectrograph collects light 5 to 15 times more efficiently and produces a purer spectrum.
- As each frame from the matrix detector includes entire spectral and spatial data, results can be processed immediately after each line measurement.
Due to the above benefits, line scan cameras can be operated with high speed yet allowing them to obtain results in real-time with minimal processing. It makes line scan cameras optimal both for industrial and airborne environments. They can be easily integrated with an automated scanner stage to offer the highest performance and data quality in laboratory and field systems.
Some filter-based cameras, particularly those based on a linearly variable filer, are often improperly compared to line scan cameras even though they collect data of a 2D area. The filter-based cameras have another severe limitation in addition to the lower light collection efficiency as they collect spectral bands from different spatial locations. It leads to co-registration challenges and much more complicated data processing than with line scan data.
More information about line scan cameras and how they compare to other hyperspectral imaging technologies can be found in:
