机器视觉 measure_projection算子

Posted 2021-08-02 沧海一笑-dj

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00. 目录

文章目录

01. 概述

measure_projection - 提取垂直于矩形或圆弧的灰度值分布。

02. 签名

measure_projection(Image : : MeasureHandle : GrayValues)

03. 描述

measure_projection提取垂直于矩形或环形弧的一维灰度值分布。这是通过平均垂直于矩形或弧长轴的“切片”中的灰度值来完成的。采样是在矩形中心的整数行和列距离（在矩形的坐标系中）的图像Image中的亚像素位置完成的。由于这涉及到可以在多个投影中重复使用的一些计算，因此算子gen_measure_rectangle2初始化这些计算，从而显著提高了measure_projection的速度。由于在灰度值的亚像素计算中存在精度和速度之间的折衷，所以在gen_measure_rectangle2中可以选择不同的插值方案（插值仅影响与图像轴不对齐的矩形）。用gen_measure_rectangle2生成的measure对象在MeasureHandle中传递。

原文描述：

measure_projection extracts a one-dimensional gray value profile perpendicular to a rectangle or annular arc. This is done by averaging the gray values in “slices” perpendicular to the major axis of the rectangle or arc. The sampling is done at subpixel positions in the image Image at integer row and column distances (in the coordinate frame of the rectangle) from the center of the rectangle. Since this involves some calculations which can be used repeatedly in several projections, the operator gen_measure_rectangle2 is used to perform these calculations only once, thus increasing the speed of measure_projection significantly. Since there is a trade-off between accuracy and speed in the subpixel calculations of the gray values, different interpolation schemes can be selected in gen_measure_rectangle2 (the interpolation only influences rectangles not aligned with the image axes). The measure object generated with gen_measure_rectangle2 is passed in MeasureHandle.

For an explanation of the concept of 1D measuring see the introduction of chapter 1D Measuring.

执行信息

●　　多线程类型：可重入（与非独占算子并行运行）。
●　　多线程范围：全局（可以从任何线程调用）。
●　　不并行处理。

04. 注意

为了效率的原因，measure_projection 会忽略Image的ROI域。如果图像中的特定区域应该从measurement中排除，则应该生成具有适当修改的参数的新measure对象。

05. 参数

Image (input_object) singlechannelimage → object (byte / uint2 / real)
　　输入图像。
MeasureHandle (input_control) measure_id → (integer)
　　measure对象句柄。
GrayValues (output_control) number-array → (real)
　　灰度值分布。