We propose, evaluate, and demonstrate the performance of an IR/optical double-image experimental setup where we capture two simultaneous images of a single object, in two different spectral bands, using a single detector array. With this arrangement, we may observe rapidly changing phenomena, at a rate of more than 1000 frames per second, without the loss of the spatial information about the test subject. We describe the optical system to perform simultaneous imaging in IR for slightly inclined optical axes. We verify the actual performance by applying the experimental method to flame analysis in the mid-IR to determine the combustion efficiency. 1. Introduction Several methods to measure the combustion efficiency have been presented recently to decrease the amount of undesirable by-products and utilize prudently a nonrenewable resource. Among them, we may mention the infrared (IR) cameras to detect the detailed temporal evolution [1] and interferometric techniques to assess the airflow and heat travel throughout the flame volume [2]. The applications with IR cameras allow studying the flame evolution; however, they only record the nontransparent imaginary surface within the flame volume that emits the radiation. Another shortcoming of this technique is that the combustion is a volume effect [3]. The radiation has to travel through the volume where some of its components are attenuated. Furthermore, combustion is time- and position-dependent phenomenon, even after the apparent steady state has been achieved. Another technique that has been successfully implemented to measure the temporal dependence of an established flame is the lateral shearing interferometry. The fringe distribution at the time of its capture indicates the flow of the heated gases. For many applications, the spatiotemporal information is even more important than the spectral one. Some multispectral imaging techniques already exist [4]. However, they require expensive and sophisticated equipment for the acquisition, storage, and processing of data. They include, for example, hyperspectral imaging, available for the Earth, the ocean, and the atmospheric monitoring from mobile platforms [5]. Their usage restricts or even limits the frame rates and introduces novel focal plane layouts [6]. They often incorporate motion as a design parameter, with carefully controlled velocity vector [7]. An alternate approach has been to redistribute the spatial information into the optical fibers, and then to analyze each fiber individually [8]. This is a flexible light conduct to move image to the
References
[1]
M. Strojnik, G. Paez, and C. Vasquez-Jaccaud, “Flame evaluation during first second after ignition in a gas stove,” in Infrared Spaceborne Remote Sensing and Instrumentation XVI, vol. 7082 of Proceedings of SPIE, pp. 70820N-1–70820N-7, SPIE, Bellingham, Wash, USA, 2008.
[2]
G. Paez and M. Strojnik, “Interferometric characterization of flames,” in Unconventional Imaging II, Proceedings of SPIE, pp. 6307–635, SPIE, Bellingham, Wash, USA, 2006.
[3]
M. Strojnik, G. Paez, and J. C. . Granados, “Flame thermometry,” in Unconventional Imaging II, vol. 6307 of Proceedings of SPIE, pp. 63070L1–63070L8, SPIE, Bellingham, Wash, USA, 2006.
[4]
B. García-Lorenzo, J. J. Fuensalida, M. A. C. Rodríguez-Hernández, et al., “EDiFiSE: equalized and diffraction-limited field spectrograph experiment,” in Ground-based and Airborne Instrumentation for Astronomy II, 70144B, vol. 7014 of Proceedings of SPIE, SPIE, Bellingham, Wash, USA, 2008.
[5]
T. Wilson and C. Davis, “Hyperspectral Remote Sensing Technology (HRST) program and the Naval EarthMap Observer (NEMO) satellite,” in Conference on Infrared Spaceborne Remote Sensing VI, vol. 3437 of Proceedings of SPIE, pp. 2–10, SPIE, Bellingham, Wash, USA, July 1998.
[6]
G. S. Libonate, B. Denley, E. E. Krueger, J. H. Rutter, J. A. Stobie, and C. L. Terzis, “Development status of the AIRS IR focal plane assembly,” in Infrared Spaceborne Remote Sensing V, vol. 3122 of Proceedings of SPIE, pp. 174–184, Bellingham, Wash, USA.
[7]
M. S. Scholl, Y. Wang, J. E. Randolph, and J. A. Ayon, “Site certification imaging sensor for mars exploration,” Optical Engineering, vol. 30, no. 5, pp. 590–597, 1991.
[8]
J. Castrellon, G. Paez, and M. Strojnik, “Remote temperature sensor employing erbium-doped silica fiber,” Infrared Physics and Technology, vol. 43, no. 3-5, pp. 219–222, 2002.
[9]
A. Aranda, M. Strojnik, G. Paez, and G. Moreno, “Two-wavelength differential thermometry for microscopic extended source,” Infrared Physics and Technology, vol. 49, no. 3, pp. 205–209, 2007.
[10]
C. Vazquez-Jaccaud, G. Paez, and M. Strojnik, “Wavelength selection method with standard deviation: application to pulse oximetry,” Annals of Biomedical Engineering, vol. 39, no. 7, pp. 1994–2009, 2011.
[11]
P. Mitra, S. L. Barnes, F. C. Case et al., “MOCVD of bandgap-engineered HgCdTe p-n-N-P dual-band infrared detector arrays,” Journal of Electronic Materials, vol. 26, no. 6, pp. 482–487, 1997.
[12]
S. D. Gunapala, S. V. Bandara, J. K. Liu et al., “1024 × 1024 Format pixel co-located simultaneously readable dual-band QWIP focal plane,” Infrared Physics and Technology, vol. 52, no. 6, pp. 395–398, 2009.
[13]
L. N. Phong and I. Shih, “Optically coated dual sensors for wavelength detection,” in Infrared Technology and Applications XXIII, vol. 3061 of Proceedings of SPIE, pp. 172–184, Bellingham, Wash, USA, 1997.
[14]
R. P. Jones, D. P. Jones, and M. Lidwell, “Dual waveband optics for the visible and mid-infrared waveband infrared,” in Infrared Technology and Applications XXIII, vol. 3061 of Proceedings of SPIE, pp. 388–395, SPIE, Bellingham, Wash, USA, 1997.
[15]
K. Kinosita, H. Itoh, S. Ishiwata, K. Hirano, T. Nishizaka, and T. Hayakawa, “Dual-view microscopy with a single camera: real-time imaging of molecular orientations and calcium,” Journal of Cell Biology, vol. 115, no. 1, pp. 67–73, 1991.
[16]
G. Garcia-Torales, M. Strojnik, and G. Paez, “Risley prisms to control wave-front tilt and displacement in a vectorial shearing interferometer,” Applied Optics, vol. 41, no. 7, pp. 1380–1384, 2002.
[17]
M. Strojnik, “From radiometric and thermographic techniques to characterize an IR target to temperature monitoring of a diabetic foot,” in Tribute to William Wolfe, Proceedings of SPIE, pp. 8483–8487, SPIE, Bellingham, Wash, USA, 2012.
[18]
I. Moreno, G. Paez, and M. Strojnik, “Dove prism with increased throughput for implementation in a rotational-shearing interferometer,” Applied Optics, vol. 42, no. 22, pp. 4514–4521, 2003.
[19]
H. Gross, F. Blechinger, and B. Achtner, Handbook of Optical Systems, Survey of Optical Instruments, vol. 402, Wiley-VCH, 2008.
[20]
C. Ramirez and M. Strojnik, “Performance evaluation of a wave-front displacement system for vectorial shearing interferometer,” Optics Communications, vol. 281, no. 3, pp. 347–355, 2008.
[21]
S. Wedemeyer-B？hm, I. Kamp, J. Bruls, and B. Freytag, “Carbon monoxide in the solar atmosphere,” Astronomy & Astrophysics, vol. 438, pp. 1043–1057, 2005.
