New baffle design and analysis of long-wave infrared camera

Wang, Chenchen; Wei, Limin; Tian, Xiaobo; Zhang, Lei; Xie, Yuan

doi:10.1016/j.ijleo.2021.166820

Cited by 4 publications

(3 citation statements)

References 2 publications

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“…To further suppress stray light from entering the optical system, multiple gradient-arranged baffles are used inside the hood. When stray light is incident on the inner wall of the hood through the apex of the baffle, scattered light in any direction of the stray light cannot reach the input pupil of the optical system directly due to the baffle of the next baffle [35]- [37].The interaction between the inner wall of the hood and the baffle constitutes a semi-closed light trap, which greatly increases the propagation path of stray light to the optical system, dissipates transmission energy many times, and has a good suppression effect on stray light from large off-axis angles. Its structure is shown in Figure 10.…”

Section: Design Of Stray Light Elimination Structurementioning

confidence: 99%

Study on Stray Light Testing and Suppression Techniques for Large-Field of View Multispectral Space Optical Systems

Lu,

Xu,

Zhang

et al. 2024

IEEE Access

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To evaluate the ability of space optical systems to suppress off-axis stray light, this paper proposes a stray light testing method for large-field of view, multispectral spatial optical systems based on point source transmittance (PST). And a stray light testing platform was developed using a high-brightness simulated light source, large-aperture off-axis reflective collimator, high-precision positioning mechanism and a double column tank to evaluate the stray light PST index of spatial optical system. On the basis of theoretical analyses, a set of calibration lenses and stray light elimination structures such as hoods, baffle and stop are designed for the accuracy calibration of stray light testing systems. The theoretical PST values of the calibration lens at different off-axis angles are analyzed by Trace Pro software simulation and compared with the measured values to calibrate the accuracy of the system. The testing results show that the PST measurement range of the system reaches 10 -3 ~10 -10 when the off-axis angles of the calibration lens are in the range of ±5°±60°. The stray light test system has the advantages of wide working band, high automation and large dynamic range, and its test results can be used in the correction of lens hood and other applications.INDEX TERMS Multi-spectrum, large-field view, stray light, point source transmittance (PST), lens hood

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Section: Design Of Stray Light Elimination Structurementioning

confidence: 99%

Study on Stray Light Testing and Suppression Techniques for Large-Field of View Multispectral Space Optical Systems

Lu,

Xu,

Zhang

et al. 2024

IEEE Access

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“…It is mainly used to evaluate the influence of stray light on rotationally symmetric systems. For some rotational asymmetric systems, the traditional evaluation method is usually to calculate the PST corresponding to the off-axis angle θ on the meridian or sagittal lines of the optical system [5][6][7] .…”

Section: Parameters For Evaluating the Influence Of Stray Light On Of...mentioning

confidence: 99%

Simulation of external stray light in airborne off-axis four mirrors telescope system

Yang¹,

Jin²,

Yang³

et al. 2022

Optical Design and Testing XII

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The off-axis four mirrors telescope has the advantages of high image quality, high resolution and high integration, which makes it a core opti-mechanical component to adapt to the future development of multiband co-aperture airborne observation and aiming systems. The simulation and suppression of external stray light in the telescope is imperative for the airborne application since this type of systems is easily affected by strong light outside the field of view. For the asymmetry of the telescope, point source transmittance (PST) as a two-dimensional function varying with the horizontal and vertical angle of stray light was set up to evaluate the influence of external stray light. Besides, the conversion relationship between the horizontal and vertical angle and the process quantity of rotations about local coordinate axis required for opto-mechanical modeling was established. Based on that, stray light simulation model of an off-axis four mirrors telescope was constructed, then PST distribution of stray lights with different spatial angles in the whole incident hemisphere space was calculated. Furthermore, the imaging effect of long-distance scene under the influence of several stray lights with large PST peak was simulated, showing that the stray lights had great interference to airborne observation. According to the found transmission paths, the internal baffles were designed to significantly reduce the peak value of PST to reach the application indices. From the re-simulation results of the imaging effect of scene, the interference of residual stray lights was finally not obvious, which could meet the use requirements of airborne photoelectric observation and aiming system.

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“…Stray light is one of the main factors affecting the performance of space optical payload. These stray light may come from the radiation of the sun, the moon, the earth's atmosphere and the instrument itself, which will cause a non-uniformity background when reaching the imaging sensor [8], [9], [10].…”

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confidence: 99%

Stray Light Suppression of Wide-Field Surveillance in Complicated Situations

Zhou

Wang

2023

IEEE Access

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Wide field and long exposure time can effectively improve the ability of space surveillance telescope to detect weak space targets. However, this is easily affected by stray light, resulting in the effective target submerged in the background of stray light. Based on the basic theory of Mathematical morphology, this paper proposes an accurate and highly robust method (ETH) for stray light suppression of space surveillance telescope, which is called the enhanced Top-Hat transform. Firstly, we define the Generalized Top-Hat transform according to the traditional Top-Hat transform. Secondly, we improve the background estimation of the traditional opening, introduce the closing to realize the multi-scale micro adjustment, and analyze the influence of the multi-scale micro adjustment on the stray light suppression and space weak targets segmentation. Finally, we introduce the noise suppression factor to reduce the residual noise in the stray light. In the field experiment, the method can effectively eliminate the interference of stray light, and greatly improves the local signal-to-noise ratio of space targets. It also shows that in a very low signal-to-noise ratio, this method can accurately and effectively segment space weak targets, and has strong robustness.

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New baffle design and analysis of long-wave infrared camera

Cited by 4 publications

References 2 publications

Study on Stray Light Testing and Suppression Techniques for Large-Field of View Multispectral Space Optical Systems

Study on Stray Light Testing and Suppression Techniques for Large-Field of View Multispectral Space Optical Systems

Simulation of external stray light in airborne off-axis four mirrors telescope system

Stray Light Suppression of Wide-Field Surveillance in Complicated Situations

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