Harms H, Boseck S, Aus H M, Lenz V
Microsc Acta. 1981 Sep;85(1):69-82.
One common method for determining the spatial resolution of a TV-microscope scanning system is to measure a sharp edge, differentiate the digitized response and calculate the Modulation Transfer Function (MTF) using the Fourier transformation. The MTF provides a measure of the information content of a digitized picture as well as the resolving power of the whole system. Knowledge of this measure is prerequisite for understanding the capabilities and limitations of computer aided techniques for analyzing cellular structures as observed in the light microscope. The information content of a digitized image depends on the MTF of the whole measurement system. Results from this study show that the information content increases almost linearly up to a sampling rate of approximately 20 pixel/micrometer and saturates at 30--35 pixel/micrometer. The MTF and the signal/noise ratio is effected by averaged multiscans. The aliasing error is presented as a function of the sampling rate for the described system. The need for this resolving power of the cell image analysis system is demonstrated by an example in the haematology. Small granules with a diameter of 0.2 to 1.0 micrometer must be registered with a high sampling rate up to 30 pixel/micrometer. The analysis of the small granules is basic for automated detection and differentiation of many leukemic conditions.
确定电视显微镜扫描系统空间分辨率的一种常用方法是测量锐利边缘，对数字化响应进行微分，并使用傅里叶变换计算调制传递函数（MTF）。MTF提供了数字化图像信息含量的一种度量，以及整个系统的分辨能力。了解此度量是理解用于分析光学显微镜下观察到的细胞结构的计算机辅助技术的能力和局限性的先决条件。数字化图像的信息含量取决于整个测量系统的MTF。这项研究的结果表明，信息含量在采样率达到约20像素/微米之前几乎呈线性增加，并在30 - 35像素/微米时达到饱和。MTF和信噪比受多次扫描平均的影响。对于所描述的系统，混叠误差表示为采样率的函数。血液学中的一个例子证明了细胞图像分析系统具有这种分辨能力的必要性。直径为0.2至1.0微米的小颗粒必须以高达30像素/微米的高采样率进行记录。对小颗粒的分析是许多白血病病情自动检测和鉴别诊断的基础。
