The NASA Perseverance rover Mast Camera Zoom (Mastcam-Z) system is a pair of zoomable, focusable, multi-spectral, and color charge-coupled device (CCD) cameras mounted on top of a 1.7 m Remote Sensing Mast, along with associated electronics and two calibration targets. The cameras contain identical optical assemblies that can range in focal length from 26 mm (\(25.5^{\circ }\, \times 19.1^{\circ }\ \mathrm{FOV}\)) to 110 mm (\(6.2^{\circ } \, \times 4.2^{\circ }\ \mathrm{FOV}\)) and will acquire data at pixel scales of 148-540 μm at a range of 2 m and 7.4-27 cm at 1 km. The cameras are mounted on the rover’s mast with a stereo baseline of \(24.3\pm 0.1\) cm and a toe-in angle of \(1.17\pm 0.03^{\circ }\) (per camera). Each camera uses a Kodak KAI-2020 CCD with \(1600\times 1200\) active pixels and an 8 position filter wheel that contains an IR-cutoff filter for color imaging through the detectors’ Bayer-pattern filters, a neutral density (ND) solar filter for imaging the sun, and 6 narrow-band geology filters (16 total filters). An associated Digital Electronics Assembly provides command data interfaces to the rover, 11-to-8 bit companding, and JPEG compression capabilities. Herein, we describe pre-flight calibration of the Mastcam-Z instrument and characterize its radiometric and geometric behavior. Between April 26\(^{th}\) and May 9\(^{th}\), 2019, ∼45,000 images were acquired during stand-alone calibration at Malin Space Science Systems (MSSS) in San Diego, CA. Additional data were acquired during Assembly Test and Launch Operations (ATLO) at the Jet Propulsion Laboratory and Kennedy Space Center. Results of the radiometric calibration validate a 5% absolute radiometric accuracy when using camera state parameters investigated during testing. When observing using camera state parameters not interrogated during calibration (e.g., non-canonical zoom positions), we conservatively estimate the absolute uncertainty to be \(<10\%\). Image quality, measured via the amplitude of the Modulation Transfer Function (MTF) at Nyquist sampling (0.35 line pairs per pixel), shows \(\mathrm{MTF}_{\mathit{Nyquist}}=0.26-0.50\) across all zoom, focus, and filter positions, exceeding the \(>0.2\) design requirement. We discuss lessons learned from calibration and suggest tactical strategies that will optimize the quality of science data acquired during operation at Mars. While most results matched expectations, some surprises were discovered, such as a strong wavelength and temperature dependence on the radiometric coefficients and a scene-dependent dynamic component to the zero-exposure bias frames. Calibration results and derived accuracies were validated using a Geoboard target consisting of well-characterized geologic samples.

NASA恒心漫游者桅杆相机变焦 (Mastcam-Z) 系统是一对可变焦、可聚焦、多光谱和彩色电荷耦合器件 (CCD) 相机，安装在 1.7 m 遥感桅杆顶部，以及相关的电子设备和两个校准目标。这些相机包含相同的光学组件，焦距范围从 26 mm ( \(25.5^{\circ }\, \times 19.1^{\circ }\ \mathrm{FOV}\) ) 到 110 mm ( \(6.2 ^{\circ } \, \times 4.2^{\circ }\ \mathrm{FOV}\)），将在 2 m 范围内获取 148-540 μm 像素尺度的数据，在 1 km 范围内获取 7.4-27 cm 像素尺度的数据. 摄像机安装在漫游车的桅杆上，立体基线为\(24.3\pm 0.1\)  cm，前束角为\(1.17\pm 0.03^{\circ }\)（每台相机）。每台相机都使用柯达 KAI-2020 CCD，具有\(1600\times 1200\)活动像素和一个 8 位滤光轮，其中包含一个 IR 截止滤光片，用于通过探测器的拜耳模式滤光片进行彩色成像，中性密度 (ND ) 用于对太阳成像的太阳能滤镜和 6 个窄带地质滤镜（总共 16 个滤镜）。相关的数字电子组件为流动站提供命令数据接口、11 到 8 位压扩和 JPEG 压缩功能。在这里，我们描述了 Mastcam-Z 仪器的飞行前校准并描述了它的辐射和几何行为。在 4 月 26 日\(^{th}\)和 5 月 9 日\(^{th}\)之间, 2019 年，在加利福尼亚州圣地亚哥的马林空间科学系统 (MSSS) 的独立校准期间获得了 45,000 张图像。在喷气推进实验室和肯尼迪航天中心的组装测试和发射操作 (ATLO) 期间获得了额外的数据。当使用测试期间调查的相机状态参数时，辐射校准的结果验证了 5% 的绝对辐射精度。当使用校准期间未询问的相机状态参数（例如，非规范变焦位置）进行观察时，我们保守地估计绝对不确定性为\(<10\%\)。图像质量，通过 Nyquist 采样（每像素 0.35 线对）的调制传递函数 (MTF) 的幅度测量，显示\(\mathrm{MTF}_{\mathit{Nyquist}}=0.26-0.50\)在所有缩放、焦点和滤镜位置，超过\(>0.2\)设计要求。我们讨论从校准中吸取的经验教训，并提出战术策略，以优化在火星运行期间获得的科学数据的质量。虽然大多数结果符合预期，但也发现了一些惊喜，例如对辐射系数的强烈波长和温度依赖性以及零曝光偏差帧的场景相关动态分量。校准结果和导出的准确性使用由充分表征的地质样本组成的 Geoboard 目标进行验证。