Compact single-shot hyperspectral imaging using a prism

Abstract

We present a novel, compact single-shot hyperspectral imaging method. It enables capturing hyperspectral images using a conventional DSLR camera equipped with just an ordinary refractive prism in front of the camera lens. Our computational imaging method reconstructs the full spectral information of a scene from dispersion over edges. Our setup requires no coded aperture mask, no slit, and no collimating optics, which are necessary for traditional hyperspectral imaging systems. It is thus very cost-effective, while still highly accurate. We tackle two main problems: First, since we do not rely on collimation, the sensor records a projection of the dispersion information, distorted by perspective. Second, available spectral cues are sparse, present only around object edges. We formulate an image formation model that can predict the perspective projection of dispersion, and a reconstruction method that can estimate the full spectral information of a scene from sparse dispersion information. Our results show that our method compares well with other state-of-the-art hyperspectral imaging systems, both in terms of spectral accuracy and spatial resolution, while being orders of magnitude cheaper than commercial imaging systems.

Snapshot hyperspectral imaging using wide dilation networks

“…In addition to diffraction gratings, prisms can be used as the dispersive element. Baek et al [17] attached a prism to a DSLR lens and reconstructed HS images based on spatial dispersion of spectra over the edges in the captured image and subsequent detection of spectral edge blur. Their solution is conceptually similar to ours: both use passive add-on device and spectral reconstruction is performed computationally.…”

“…The RIP diffuser method [18] suffers from high degree of blur, failing to produce sharp images even at medium resolutions. On the other hand, the newer work of Baek et al [17] produces comparable spatial resolution, but is computationally much more expensive, relies on an alternative dispersion element, and requires presence of strong edges in the image due to the properties of the reconstruction algorithm. Similarly, the method of Habel et al [24] achieves spatial and spectral resolutions comparable to our method, but requires more complex optical device and camera-specific calibration.…”

“…To combine low cost with fast image acquisition, we need snapshot imaging without active mechanical elements. This can be done by using a diffraction grating filter [14][15][16], a prism [17], or an optical diffuser [18], followed by algorithmic reconstruction of the HS image. The existing work in this direction, however, has serious limitations.…”

“…The existing work in this direction, however, has serious limitations. The early works using a diffraction grating employ linear reconstruction models that can only produce images of extremely low resolution [14,15], whereas the more recent work using a prism requires time-consuming post-processing for creating the HS image (Baek et al [17] report 45 min for creating a Fig. 1 (Top left) The custom diffraction grating mounted in front of a DSLR camera.…”

Development of a hyperspectral imaging technique with internal scene scan for analysing the chemistry of food degradation

“…6,8 For example, such coded light patterns for object illumination can be generated by a digital micromirror device. 7 Pixelated filters (either interference type 9 or diffraction type 10 ), ordinary refractive prisms 11 or Michelson interferometers 4,7 are suited to equip an imaging device with spectral resolving power. However, most of the proposed snapshot techniques require a computational image formation model to recover images at discrete wavelengths.…”