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Multi-sensor fusion of infrared and electro-optic signals for high resolution night images.

Huang X, Netravali R, Man H, Lawrence V - Sensors (Basel) (2012)

Bottom Line: The framework requires four main steps: (1) inverse filter-based IR image transformation; (2) EO image edge detection; (3) registration; and (4) blending/superimposing of the obtained image pair.Simulation results show both blended and superimposed IR images, and demonstrate that blended IR images have better quality over the superimposed images.Additionally, based on the same steps, simulation result shows a blended IR image of better quality when only the original IR image is available.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical and Computer Engineering, Stevens Institute of Technology, Hoboken, NJ 07030, USA. xhuang3@stevens.edu

ABSTRACT
Electro-optic (EO) image sensors exhibit the properties of high resolution and low noise level at daytime, but they do not work in dark environments. Infrared (IR) image sensors exhibit poor resolution and cannot separate objects with similar temperature. Therefore, we propose a novel framework of IR image enhancement based on the information (e.g., edge) from EO images, which improves the resolution of IR images and helps us distinguish objects at night. Our framework superimposing/blending the edges of the EO image onto the corresponding transformed IR image improves their resolution. In this framework, we adopt the theoretical point spread function (PSF) proposed by Hardie et al. for the IR image, which has the modulation transfer function (MTF) of a uniform detector array and the incoherent optical transfer function (OTF) of diffraction-limited optics. In addition, we design an inverse filter for the proposed PSF and use it for the IR image transformation. The framework requires four main steps: (1) inverse filter-based IR image transformation; (2) EO image edge detection; (3) registration; and (4) blending/superimposing of the obtained image pair. Simulation results show both blended and superimposed IR images, and demonstrate that blended IR images have better quality over the superimposed images. Additionally, based on the same steps, simulation result shows a blended IR image of better quality when only the original IR image is available.

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Related in: MedlinePlus

FLIR imaging system. (a) Effective MTF of the detectors, /D (u, v)/; (b) Diffraction-limited OTF for the optics, H (u, v); (c) Overall system MTF; (d) Continuous system PSF (enlarged PSF on right side).
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f2-sensors-12-10326: FLIR imaging system. (a) Effective MTF of the detectors, /D (u, v)/; (b) Diffraction-limited OTF for the optics, H (u, v); (c) Overall system MTF; (d) Continuous system PSF (enlarged PSF on right side).

Mentions: We consider a particular IR imaging system as an example; the typical system considered is the forward-looking infrared (FLIR) imager. In order to make our adopted PSF realistic, parameter settings of this PSF are the same as in [8]. This system has square detectors of size a = b = 0.040 mm, the imager is equipped with 100 mm f/3 optics, the center wavelength = 0.004 mm and the cutoff frequency 83.3 cycles/mm is used for the OTF calculation. In Figure 2, Figure 2(a) shows the effective MTF of the detectors, /D (u, v)/, and Figure 2(b) shows the diffraction-limited OTF for the optics, H (u, v). The overall system MTF is shown in Figure 2(c), and the continuous system PSF is shown in Figure 2(d).


Multi-sensor fusion of infrared and electro-optic signals for high resolution night images.

Huang X, Netravali R, Man H, Lawrence V - Sensors (Basel) (2012)

FLIR imaging system. (a) Effective MTF of the detectors, /D (u, v)/; (b) Diffraction-limited OTF for the optics, H (u, v); (c) Overall system MTF; (d) Continuous system PSF (enlarged PSF on right side).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472830&req=5

f2-sensors-12-10326: FLIR imaging system. (a) Effective MTF of the detectors, /D (u, v)/; (b) Diffraction-limited OTF for the optics, H (u, v); (c) Overall system MTF; (d) Continuous system PSF (enlarged PSF on right side).
Mentions: We consider a particular IR imaging system as an example; the typical system considered is the forward-looking infrared (FLIR) imager. In order to make our adopted PSF realistic, parameter settings of this PSF are the same as in [8]. This system has square detectors of size a = b = 0.040 mm, the imager is equipped with 100 mm f/3 optics, the center wavelength = 0.004 mm and the cutoff frequency 83.3 cycles/mm is used for the OTF calculation. In Figure 2, Figure 2(a) shows the effective MTF of the detectors, /D (u, v)/, and Figure 2(b) shows the diffraction-limited OTF for the optics, H (u, v). The overall system MTF is shown in Figure 2(c), and the continuous system PSF is shown in Figure 2(d).

Bottom Line: The framework requires four main steps: (1) inverse filter-based IR image transformation; (2) EO image edge detection; (3) registration; and (4) blending/superimposing of the obtained image pair.Simulation results show both blended and superimposed IR images, and demonstrate that blended IR images have better quality over the superimposed images.Additionally, based on the same steps, simulation result shows a blended IR image of better quality when only the original IR image is available.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical and Computer Engineering, Stevens Institute of Technology, Hoboken, NJ 07030, USA. xhuang3@stevens.edu

ABSTRACT
Electro-optic (EO) image sensors exhibit the properties of high resolution and low noise level at daytime, but they do not work in dark environments. Infrared (IR) image sensors exhibit poor resolution and cannot separate objects with similar temperature. Therefore, we propose a novel framework of IR image enhancement based on the information (e.g., edge) from EO images, which improves the resolution of IR images and helps us distinguish objects at night. Our framework superimposing/blending the edges of the EO image onto the corresponding transformed IR image improves their resolution. In this framework, we adopt the theoretical point spread function (PSF) proposed by Hardie et al. for the IR image, which has the modulation transfer function (MTF) of a uniform detector array and the incoherent optical transfer function (OTF) of diffraction-limited optics. In addition, we design an inverse filter for the proposed PSF and use it for the IR image transformation. The framework requires four main steps: (1) inverse filter-based IR image transformation; (2) EO image edge detection; (3) registration; and (4) blending/superimposing of the obtained image pair. Simulation results show both blended and superimposed IR images, and demonstrate that blended IR images have better quality over the superimposed images. Additionally, based on the same steps, simulation result shows a blended IR image of better quality when only the original IR image is available.

Show MeSH
Related in: MedlinePlus