城市夜光遥感相机成像质量分析

Image quality analysis of urban luminous remote sensing camera

  • 摘要: 微光遥感影像被广泛应用于社会经济估算、城市监测、生态环境评估以及公共健康等领域。利用微光遥感在夜间和晨昏时段等低照度条件下进行地物探测,可与传统的日间遥感形成互补,形成全天时的对地观测能力。但是在低照度环境下,遥感相机的成像质量会随着相机进光量的衰减而急剧衰退,因此,如何提高图像信噪比是微光遥感需要重点关注的。针对前期研制的某夜光遥感相机的信噪比(SNR)进行了详细分析和建模,在面阵凝视模式下,分析信噪比与积分时间、地面辐亮度之间的函数关系,发结果表明,当积分时间大于2 ms时,信噪比优于10 dB;当积分时间大于15 ms时,信噪比优于20 dB。在条带成像模式下,分析信噪比与行频及TDI级数的关系,结果表明,TDI级数一定的情况下,行频越高,信噪比越低;行频一定的情况下,TDI级数增加,信噪比增大,但是信噪比增大的速率随着TDI级数增加逐渐减缓。

     

    Abstract: Luminous remote sensing has become increasingly active in the field of remote sending. Luminous remote sensing images have been widely used in social and economic estimation, urban monitoring, ecological environment assessment and public health. Using luminous remote sensing to detect ground objects in low illumination conditions such as nighttime and twilight, it is complementary to traditional daytime remote sensing to form all-day earth observation capability. However, in low illumination environment, the image quality of remote sensing camera will decline sharply with the attenuation of camera light input, so how to improve the signal-to-noise ratio of remote sensing image is the focus of luminous remote sensing. The SNR of a remote sensing camera developed in the early stage is analyzed and modeled in detail. The functional relationship between SNR, integration time and ground radiation brightness is given in the face array staring mode. When the integration time than 2 ms, the SNR is better than 10 dB; when the integration time is greater than 15 ms, the SNR is better than 20 dB. In strip imaging mode, the relation between SNR and line frequency and TDI series is given. When the TDI series is constant, the SNR decreases with the increase of line frequency; when the line frequency is constant, the SNR increase with the increase of TDI series, but the speed of SNR increase gradually slows down with the increase of TDI series.

     

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