高动态范围测试图卡高级定制测试图卡
高动态范围（HDR）测试卡的密度范围超过120dB（光密度>0.6）。该测试卡可以测量相机单个图像色调响应、噪声和HDR相机单个图像而不是多个图像的动态范围以及包围图像的曝光。ITHDR36的斜边缘与MTF测量比例为4:1。边缘具有一个MTF50≥16周期/毫米，这是比喷墨图卡还要好约3倍。中间的灰色背景密度非常类似于36补丁动态范围卡，实现与自动曝光相机的正确曝光。HDR的黑色背景测试目标相机自动曝光模式倾向于使感光过度明亮的补丁。
高动态范围测试图卡高级定制测试图卡
Details
The High Dynamic Range (HDR) test chart has a density range exceeding 120dB (optical density >6.0). This chart allows you to measure the tonal response, noise, and dynamic range of HDR cameras with a single image instead of multiple, exposure bracketed images. The ITHDR36 contains slanted edges with 4:1 contrast for measuring MTF. The edges have an MTF50 >= 16 cycles/mm, which is about 3 times better than the best inkjet charts. The middle gray background density closely resembles our 36-patch Dynamic Range target, enabling proper exposure with automatic exposure cameras. HDR test targets with black backgrounds tend to overexpose the brighter patches with auto-exposure cameras.
The HDR chart’s active area of 197 x 235mm is a good fit for both the DNP Standard Color Viewer and ITI LED lightbox. Imatest recommends using the HDR Target with a high illuminance light source (close to 10,000 Lux) in order to provide sufficient light to test image sensors over their range of sensitivity. The chart is well suited for measuring both camera and sensor dynamic range, which are fundamentally different. Camera DR measurements are affected by flare (stray) light in the lens. They represent real-world performance. Sensor measurements are based on the patch pixel and noise levels in unprocessed RAW images, using the technique described in Multicharts/Multitest/eSFR ISO Noise, which fits data to an equation based on dark and photon noise.
The Imatest 36-patch High Dynamic Range Target includes an acrylic frame which can be excluded.
