论文标题
用激光斑点和对Nancy Grace Roman Space望远镜检测器阵列的应用和应用
Pixel centroid characterization with laser speckle and application to the Nancy Grace Roman Space Telescope detector arrays
论文作者
论文摘要
南希·格雷斯·罗马（Nancy Grace Roman）太空望远镜将使用其宽场仪器在近红外进行一套天空调查。这些调查的几个科学目标，例如使用弱重力透镜测量宇宙结构的生长，需要精心控制天文对象图像的仪器相关扭曲。罗马将飞行4KX4K Teledyne H4RG-10红外探测器阵列。本文研究了像素质心是否通过通过双缝孔将激光斑点图案投射到非飞行探测器阵列上，通过将激光斑点图案投射到常规网格上。我们开发了一种从随机斑点模式中重建像素质心偏移的方法。由于测试设置的方向，此处仅测量X-Offset。我们在模拟上测试了该方法，并通过将人工偏移注入真实图像中。我们使用来自不同斑点实现的重建的互相关来确定像素偏移映射中有多少差异是信号（固定在检测器上），以及噪声是多少。在64x64像素贴片上进行了重建，并拟合了从像素索引到位置的最佳拟合线性映射，我们发现从0.0107 Pixels RMS的常规网格中有X（列）方向的残留质心偏置（不包括整个行转换到另一个spemkle模式），这是我们的平台模式。如果我们考虑来自二次映射而不是线性映射的残差，则降低到0.0097 pix rms。这些RMS偏移既包括物理像素偏移量，也包括由于重建中的串扰和剩余的系统错误而引起的任何明显偏移。我们评论斑点场景测量值的优点和缺点，作为表征天文探测器中像素级行为的工具。
The Nancy Grace Roman Space Telescope will use its wide-field instrument to carry out a suite of sky surveys in the near infrared. Several of the science objectives of these surveys, such as the measurement of the growth of cosmic structure using weak gravitational lensing, require exquisite control of instrument-related distortions of the images of astronomical objects. Roman will fly 4kx4k Teledyne H4RG-10 infrared detector arrays. This paper investigates whether the pixel centroids are located on a regular grid by projecting laser speckle patterns through a double slit aperture onto a non-flight detector array. We develop a method to reconstruct the pixel centroid offsets from the stochastic speckle pattern. Due to the orientation of the test setup, only x-offsets are measured here. We test the method both on simulations, and by injecting artificial offsets into the real images. We use cross-correlations of the reconstructions from different speckle realizations to determine how much of the variance in the pixel offset maps is signal (fixed to the detector) and how much is noise. After performing this reconstruction on 64x64 pixel patches, and fitting out the best-fit linear mapping from pixel index to position, we find that there are residual centroid offsets in the x (column) direction from a regular grid of 0.0107 pixels RMS (excluding shifts of an entire row relative to another, which our speckle patterns cannot constrain). This decreases to 0.0097 pix RMS if we consider residuals from a quadratic rather than linear mapping. These RMS offsets include both the physical pixel offsets, as well as any apparent offsets due to cross-talk and remaining systematic errors in the reconstruction. We comment on the advantages and disadvantages of speckle scene measurements as a tool for characterizing the pixel-level behavior in astronomical detectors.
