Dual field-of-view midwave infrared optical design and athermalization analysis

Kuo, Chih-Wei; Lin, Chih‐Lung; Han, Chien-Yuan

doi:10.1364/ao.49.003691

Cited by 15 publications

(6 citation statements)

References 23 publications

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“…Athermalization techniques aim for realizing a stable focal power within a wide range of temperatures. Typically, there are three types: passive optical, [ 6 ] active mechanical, [ 7 ] and passive mechanical methods. [ 8 ] These solutions compensate for thermal defocus, respectively, by the combination of optical materials, thermal expansion of mechanical components, and motorized mechanical parts.…”

Section: Introductionmentioning

confidence: 99%

Temperature‐Robust Learned Image Recovery for Shallow‐Designed Imaging Systems

Chen

Liu

et al. 2022

Advanced Intelligent Systems

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Imaging systems are widely applied in harsh environments where the performance of shallow‐designed systems may deviate from expectation. As a representative scenario, environmental temperature variation may degrade image quality due to thermal defocus and sensor response, resulting in blur and noise. However, extensive athermalization in optics usually requires a complex design process and is limited by materials. Herein, a multibranch computational imaging scheme is developed, using emerging generative adversarial networks as the postprocessing to compensate for degradation of all kinds caused by thermal defocus and noise. In addition, a temperature controllable data acquisition, division, and mixture scheme is described to facilitate effective datasets for model robustness. Experiments on a vehicle lens and a mobile phone lens reveal that the proposed multibranch learned strategy notably increases image quality in the temperature range of 0–80 °C, and outperforms conventional athermalization in most instances, which is beneficial to lowering the design and manufacturing costs of imaging systems.

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Section: Introductionmentioning

confidence: 99%

Temperature‐Robust Learned Image Recovery for Shallow‐Designed Imaging Systems

Chen

Liu

et al. 2022

Advanced Intelligent Systems

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“…As a result, the change of temperature makes light paths change and imaging quality is dropping dramatically. This problem has caused wide attention in the fields of optical-electric imaging and has been the hotspot of optical design [1,2] and information optics [3,4] . Athermalization can reduce the thermal effect on infrared system imaging quality and image clearly in the wide temperature ranges.…”

Section: Introductionmentioning

confidence: 99%

Infrared lens thermal effect: equivalent focal shift and calculating model

et al. 2014

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It's well-know that the focal shift of infrared lens is the major factor in degeneration of imaging quality when temperature change. In order to figure out the connection between temperature change and focal shift, partial differential equations of thermal effect on light path are obtained by raytrace method, to begin with. The approximately solution of the PDEs show that focal shift is proportional to temperature change. And a formula to compute the proportional factor is given. In order to understand infrared lens thermal effect deeply, we use defocus by image plane shift at constant temperature to equivalently represent thermal effect on infrared lens. So equivalent focal shift (EFS) is defined and its calculating model is proposed at last. In order to verify EFS and its calculating model, Physical experimental platform including a motorized linear stage with built-in controller, blackbody, target, collimator, IR detector, computer and other devices is developed. The experimental results indicate that EFS make the image plane shift at constant temperature have the same influence on infrared lens as thermal effect and its calculating model is correct.

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“…Thermal imaging technology, both midwave infrared (MWIR, wavelength from 3 to 5 μm) and longwave infrared (LWIR, wavelength from 8 to 12 μm) spectra have been extensively discussed in numerous studies over the past few decades. [1][2][3][4] Their applications cover a wide range of different fields, such as for industrial temperature measurement, noninvasive medical inspection, military stealth surveillance, and security biometrics recognition. Visual processing of these thermal images is commonly accomplished by utilizing the intensity threshold algorithm in which the intensities of the target pixels are compared with those of the background.…”

Section: Introductionmentioning

confidence: 99%

Achromatic triplet and athermalized lens assembly for both midwave and longwave infrared spectra

Kuo

2013

Opt. Eng

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Analytic solutions for finding the achromatic triplet in the midwave and longwave infrared spectra simultaneously are explored. The relationship between the combination of promising refractive materials and the system's optical power is also formulated. The principles for stabilizing the effective focal length of an air-spaced lens group with respect to temperature are explored, and the thermal properties of the optical component and mechanical elements mutually counterbalanced. An optical design based on these achromatic and athermal theories is demonstrated, and the image quality of the lens assembly seems to approach the diffractive limitation. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Dual field-of-view midwave infrared optical design and athermalization analysis

Cited by 15 publications

References 23 publications

Temperature‐Robust Learned Image Recovery for Shallow‐Designed Imaging Systems

Temperature‐Robust Learned Image Recovery for Shallow‐Designed Imaging Systems

Infrared lens thermal effect: equivalent focal shift and calculating model

Achromatic triplet and athermalized lens assembly for both midwave and longwave infrared spectra

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