共查询到15条相似文献,搜索用时 62 毫秒
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本文介绍了TIFF图象文件的文件结构和从TIFF格式文件复原图象的方法,以及该图象在TVGA上的各种调色板的设置及显示。 相似文献
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本文介绍了TIFF图象文件的文件结构和从TIFF格式文件复原图象的方法,以及该图象在TVCA上的各种调色板的设置及显示。 相似文献
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本文把快速Hartley变换引入到天文数据处理中,提出了计算Cells坐标的公式,编制了FHT算法程序。FHT与Cooley—Tukey的FFT相似,但FHT是实变换,不存在复运算,因此比FFT快得多。利用DHT与离散Fourier变换(DFT)的关系,DFT可以由FHT求出。FHT将广泛地用于谱分析,信号处理,图像处理等领域。 相似文献
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We present a procedure to extract bright loop features from solar EUV images. In terms of image intensities, these features
are elongated ridge-like intensity maxima. To discriminate the maxima, we need information about the spatial derivatives of
the image intensity. Commonly, the derivative estimates are strongly affected by image noise. We therefore use a regularized
estimation of the derivative, which is then used to interpolate a discrete vector field of ridge points; these “ridgels” are
positioned on the ridge center and have the intrinsic orientation of the local ridge direction. A scheme is proposed to connect
ridgels to smooth, spline-represented curves that fit the observed loops. Finally, a half-automated user interface allows
one to merge or split curves or eliminate or select loop fits obtained from this procedure. In this paper we apply our tool
to one of the first EUV images observed by the SECCHI instrument onboard the recently launched STEREO spacecraft. We compare
the extracted loops with projected field lines computed from near-simultaneous magnetograms measured by the SOHO/MDI Doppler
imager. The field lines were calculated by using a linear force-free field model. This comparison allows one to verify faint
and spurious loop connections produced by our segmentation tool and it also helps to prove the quality of the magnetic-field
model where well-identified loop structures comply with field-line projections. We also discuss further potential applications
of our tool such as loop oscillations and stereoscopy. 相似文献
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本文利用CCD动态范围大且便于数值处理的优点,观测月晕中(强背景上)的弱源。在背景尚未使CCD片子饱和时,即停止露光,存入计算机,多次露光,然后在计算机内多幅叠加,减去背景,显出弱源。通过观测试验和定量估算,结果表明,曝光重叠法,用10幅图叠加时能提高信噪比2.65倍。实测与理想情况符合较好。 相似文献
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幸运成像技术是用于消除天文图像中大气湍流影响的高分辨率图像重建技术,传统的基于中央处理器的幸运成像算法难于实时化。利用现场可编程门阵列并行处理的优势,设计了一种基于现场可编程门阵列的幸运成像算法并构建了一个实验系统。该系统用现场可编程门阵列完成了选图、配准、叠加的全部幸运成像算法流程,所得高分辨率图像与基于传统中央处理器算法处理的结果完全相同,但幸运成像算法的处理速度比传统中央处理器的处理速度快19倍。该算法在现场可编程门阵列上的实现,为幸运成像技术的实时或准实时化提供了一种可行的方案。 相似文献