Design and Realization of Spectral Imaging Systems Based on Microlens Arrays

Fig. 1. Overall system structure diagram. (a) 2D spatial image; (b) microlens array segmentation image; (c) microlens array integral image; (d) 3D spectral image

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Fig. 2. Mathematical model of microlens unit

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Fig. 3. Light tracing results of microlens arrays under different incident half-cone angles. (a) 3.6°; (b) 41.2°; (c) 42.0°

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Fig. 4. Spectral PSF curves of collimating and focusing system at different focal lengths

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Fig. 5. Simulation schematic of spectral resolving power

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Fig. 6. View of dispersive spot profiles in the detector before and after increasing the focal length of focusing lens. (a) f_c=30 mm, f_f= 30 mm; (b) f_c=30 mm, f_f=50 mm

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Fig. 7. View of dispersive spot profiles in the detector before and after increasing the focal length of collimating lens. (a) f_c=40 mm, f_f=40 mm; (b) f_c=50 mm, f_f=50 mm

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Fig. 8. System diagram

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Fig. 9. Spectral position calibration test results. (a) Test results without filters; (b) test results with different filters

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Fig. 10. Gaussian fitting results for different wavelength spots

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Fig. 11. Positions of spot center in the dispersion fringes for each wavelength band

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Fig. 12. Spatial resolution test results

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Fig. 13. Color plate picture and spectral imaging results for each band

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Table 1. Simulation parameters of microlens arrays
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Table 1. Simulation parameters of microlens arrays
Pitch /μm Curvature radius /mm Focal length /mm Thicknesses /mm Material
30 0.023 0.06 1 BK7

Table 2. Correspondence between spectral PSF width and spectral resolution under different collimating and focusing systems

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Table 2. Correspondence between spectral PSF width and spectral resolution under different collimating and focusing systems

Set	Focal length of collimating system	Focal length of focusing system	Linear dispersion power	PSF width	Spectral PSF width	Spectral resolution
1	$f_{c}$	$f_{f}$	$D_{l}$	$w$	$w / D_{l}$	$R$
2	$f_{c}$	1.7 $f_{f}$	1.7 $D_{l}$	1.7 $w$	$w / D_{l}$	$R$
3	1.3 $f_{c}$	1.3 $f_{f}$	1.3 $D_{l}$	$w$	0.75 $w / D_{l}$	1.3 $R$
4	1.7 $f_{c}$	1.7 $f_{f}$	1.7 $D_{l}$	$w$	0.6 $w / D_{l}$	1.7 $R$

Table 3. System performance indicators and main component parameters

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Table 3. System performance indicators and main component parameters

Item	Parameter	Value
Imaging lens	F-number	8
Imaging lens	Field of view /(°)	4
Microlens array	Pitch /mm	0.03
Microlens array	Focal length /mm	0.07
Prism	Wedge angle /(°)	5
Collimating lens	Focal length /mm	42
Focusing lens	Focal length /mm	40
Detector	Size of photosensitive surface /(")	1/1.8
	Pixel size /(μm×μm)	2.4×2.4
	Resolution /(pixel×pixel)	3072×2048
System	Wavelength range /nm	450‒685
	Target distance /m	>2.5
	Spatial channel number	12000
	Spectral channel wavelength /nm	450, 500, 532, 589, 628, 685

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Dongrui Li, Jintao Liu, Songhua Wu. Design and Realization of Spectral Imaging Systems Based on Microlens Arrays[J]. Acta Optica Sinica, 2025, 45(4): 0411001

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