Sometimes it is necessary to perform analyses on the mm-cm scale. For this, neither common optics nor the microscopic solution with a relay lens is suitable. Therefore, we evaluated the option of adding some close-up lenses to a common lens.
Macroscopic Scale
In the following setup, we used a hyperspectral FireflEYE 496 Blue and designed the optical path for a macro extension from Schneider-Kreuznach. To achieve an image size of 2×2 mm, the necessary tube elongation had to be 480 mm long.
With this length, the optics needed to be stabilized with an aluminum frame. Although the first tests delivered satisfying results, we found the design to be impractical for use even in the safe environment of a laboratory.
Adding Close-Up Lenses
After further design studies, we found that using a common lens in combination with close-up lenses, also from Schneider-Kreuznach, was effective. We used the lens with the closest field of view available, namely the 50 mm lens with a 6.5° FOV. Using a mounting adapter on top of the 50 mm lens allows adding a close-up lens, which directly results in a spot size in the mm-cm scale.
The advantage of this solution for the customer is significant. It is now possible to add various close-up lenses individually, meeting each requirement for spot size on the macroscopic scale. The accuracy of the camera is not affected because it is calibrated with the 50 mm lens in our laboratory, and the transmission rate of the close-up lenses is almost 100%.
„Bug Report“
To demonstrate the potential of the macro setup onboard the S496 Blue, we used a colorful test bug and analyzed the quality of the sharpness and the spectral reflectance. The bug is approximately 4 cm long, and different parts of it were placed in the image spot of the camera.
Check out the images below and see for yourself the spectral and spatial quality of the macroscopic solution.
About the Author
Dr. Matthias Locherer has been the Sales Director at Cubert GmbH since 2017. With a PhD in Earth Observation from Ludwig Maximilian University of Munich, he brings extensive expertise in remote sensing, spectral imaging, and data analysis. Matthias has contributed to numerous research projects and publications, particularly in the multispectral monitoring of biophysical and biochemical parameters using hyperspectral satellite missions. His deep knowledge of optical measurement techniques and physical modeling makes him a key driver in advancing innovative hyperspectral technologies at Cubert.
