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CN-115876440-B - Resolution board, resolution testing system and method for measuring resolution capability

CN115876440BCN 115876440 BCN115876440 BCN 115876440BCN-115876440-B

Abstract

The invention discloses a resolution board, a resolution testing system and a method for measuring resolution capability, wherein the resolution board comprises a board body, at least one group of slit groups are arranged on the board body, each slit group comprises two parallel slits penetrating through the board body along a path, each slit has a width in the direction perpendicular to the opening path, the slits are arranged at equal widths along the opening path, the shapes and the widths of the two slits are consistent, the two slits are arranged at intervals, and the distance between the two slits is equal to the width of each slit. Through set up the slit group that has two slits on the plate body that tungsten material was made, high energy X ray can form at least one set of image that has two strips on imaging plate through slit group, can obtain corresponding graph through simple measurement and many times experiments, easy operation, and can embody the resolving power of ray point source under corresponding amplification ratio and slit width directly perceived accuracy.

Inventors

  • Shi Huantong
  • WANG YIZHU
  • CHEN LI
  • WU JIAN
  • LI XINGWEN
  • DENG YUNKUN
  • PENG JING
  • ZHAO XIANPING
  • WANG KE

Assignees

  • 西安交通大学

Dates

Publication Date
20260508
Application Date
20221130

Claims (7)

  1. 1. A method for measuring resolution capability of a resolution test system is characterized in that, The resolution test system comprises an imaging plate (2) and a resolution plate, wherein the imaging plate is made of a scintillator; The resolution plate comprises a plate body (1), wherein at least one group of slit groups (11) is arranged on the plate body, each slit group (11) comprises two parallel slits (111) penetrating through the plate body along a path, each slit (111) has a width in the direction perpendicular to the opening path, the slits (111) are arranged at equal widths along the opening path, the shapes and the widths of the two slits (111) are consistent, the two slits (111) are arranged at intervals, and the distance between the two slits (111) is equal to the width of the slit (111); The method comprises the following steps: Placing the resolution plate between a ray point source and an imaging plate, setting the distance between the resolution plate and the ray point source as x1, and setting the distance between the resolution plate and the imaging plate as x2 to obtain an amplification ratio M= (x1+x2)/x 1; Irradiating a high X-ray energy source towards the resolution plate to form at least one group of image groups on the imaging plate, wherein the image groups comprise two strips with the same width and gray scale; Measuring gray values f2 of the central positions of two strips in the same group of images and gray values f1 of the central positions of the areas between the two strips, and calculating the light intensity ratio f1/f2; setting the width of the slit as d, and drawing a graph according to the relation among the light intensity ratio, the width of the slit and the amplification ratio; setting the width of the slit as d, and drawing a graph according to the relation between the width of the slit and the amplification ratio according to the light intensity ratio, wherein the step of drawing the graph comprises the following steps: obtaining a product formula d (M/M-1) of the width of the slit and the amplification ratio, taking the value of the product formula as an abscissa, taking the value of the light intensity ratio corresponding to the value of the product formula as an ordinate, and correspondingly obtaining a coordinate point on a two-dimensional coordinate system; Changing the amplification ratio to obtain a plurality of coordinate points on a two-dimensional coordinate system, and sequentially connecting the plurality of coordinate points to form the graph.
  2. 2. The method for measuring resolution of a resolution test system according to claim 1, wherein four slit groups (11) are provided on the board body (1), each slit group (11) includes two slits (111), and the widths of the slits (111) corresponding to the four slit groups (11) increase from low to high.
  3. 3. Method for measuring resolution of a resolution test system according to claim 2, characterized in that four groups of slits (11) are arranged on the plate body (1) in such a way that the width of the corresponding slits (111) is from small to large or from large to small.
  4. 4. The method for measuring resolution of a resolution test system according to claim 2, wherein the slit (111) comprises two symmetrically arranged sub-slits, the sub-slits are formed on the plate body (1) along a semicircular track from one end of the plate body (1) as a head end, and the head ends and the other ends of the two sub-slits are respectively opposite to each other and are arranged at intervals.
  5. 5. The method for measuring resolution of a resolution testing system according to claim 4, wherein the slits (111) corresponding to the four slit groups (11) are concentrically arranged on the board body (1).
  6. 6. The method for measuring resolution of a resolution testing system according to claim 5, wherein a group of linear slit groups (12) is further arranged inside the slit (111) with the smallest radius on the plate body (1), the linear slit groups (12) comprise two linear slits (121), and the width of the linear slits (121) is consistent with the width of the slit (111) with the smallest radius.
  7. 7. A method of measuring resolving power of a resolution testing system according to any of claims 2-6, characterized in that the width of the four sets of slits (111) is 0.2mm, 0.25mm, 0.3mm and 0.5mm in order from small to large.

Description

Resolution board, resolution testing system and method for measuring resolution capability Technical Field The invention relates to the technical field of resolution capability test, in particular to a resolution board, a resolution capability test system and a method for measuring resolution capability. Background There are two general methods for measuring the resolution of a high-energy X-ray point source today, one is to obtain a line spread Function (LINE SPREAD Function, LSF) through single slit plate imaging, then obtain an optical modulation transfer Function (Modulation Transfer Function, MTF) through one-dimensional fourier transform, the ordinate is a modulation degree, the abscissa is a spatial frequency, that is, the resolution, and the spatial frequency corresponding to the modulation degree when 0.05 is taken is generally considered to be a limit resolution, and the other is to obtain an edge blurred image through a cylindrical tungsten step (Rolled-edge), that is, an edge spread Function (EDGE SPREAD Function, ESF), obtain an LSF through differentiation, and the subsequent steps are the same as the previous method. In fact, although the two measurement methods are greatly different, the final purpose is to measure the resolution of the point source for imaging the object, and when the single slit or cylindrical step is adopted to measure the resolution, the defect that the calculation data is complicated exists, and when the resolution is measured by the first method, the standard distribution function form cannot be obtained in most cases, but the calculation is simplified into the distribution functions to calculate the MTF, so that the error of the resolution measurement is caused. Disclosure of Invention The invention aims to provide a resolution board, a resolution testing system and a method for measuring resolution capability, so as to overcome the defect that the existing calculation data are complex and cause resolution measurement errors. A resolution plate, the resolution plate comprising: The plate body, be provided with at least a set of slit group on the plate body, the slit group is including running through along a route two parallel arrangement's on the plate body slit, the slit has the width in the direction that perpendicular to its path of seting up, the slit sets up along the direction isopiestic of its path of seting up, the appearance and the width of two slits are unanimous, two slit interval sets up, just the interval of two slits is equal to the width of slit. In some embodiments of the resolution board, four slit groups are disposed on the board body, each slit group includes two slits, and widths of the slits corresponding to the four slit groups increase from low to high. In some embodiments of the resolution plate, four groups of the slits are arranged on the plate body from small to large or from large to small according to the width of the corresponding slits. In some embodiments of the resolution board, the slit includes two symmetrically arranged sub-slits, the sub-slits are formed on the board body along a semicircular track from one end of the board body as a head end, and the head ends and the other ends of the two sub-slits are respectively opposite to each other and are arranged at intervals. In some embodiments of the resolution plate, the slits corresponding to the four slit groups are concentrically arranged on the plate body. In some embodiments of the resolution board, a group of linear slit groups is further disposed on the board body inside the slit with the smallest radius, and the linear slit groups comprise two linear slits, and the width of the linear slit is consistent with the width of the slit with the smallest radius. In some embodiments of the resolution plate, the widths of the four sets of slits are 0.2mm, 0.25mm, 0.3mm, and 0.5mm in order from small to large. In another aspect, an embodiment of the present invention provides a resolution test system, including: an imaging plate made of a scintillator, and The resolution plate described above. The embodiment of the invention also provides a method for measuring the resolution capability by adopting the resolution test system, which comprises the following steps: Placing the resolution plate between a ray point source and an imaging plate, setting the distance between the resolution plate and the ray point source as x1, and setting the distance between the resolution plate and the imaging plate as x2 to obtain an amplification ratio M= (x1+x2)/x 1; Irradiating a high X-ray energy source towards the resolution plate to form at least one group of image groups on the imaging plate, wherein the image groups comprise two strips with the same width and gray scale; Measuring gray values f2 of the central positions of two strips in the same group of images and gray values f1 of the central positions of the areas between the two strips, and calculating the light intensity ratio f1/f2; Setting th