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Calibration method of a detector and device and equipment using the calibration method

A calibration method and detector technology, applied in computer tomography scanners, echo tomography, etc., can solve problems such as poor installation of grid sheets

Active Publication Date: 2019-10-08
SHANGHAI UNITED IMAGING HEALTHCARE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The technical problem to be solved by the present invention is to solve the artifacts caused by poor installation of the grid sheet through an algorithm, thereby avoiding repeated adjustment of the grid sheet and rework installation caused by image artifacts caused by the tilt of the grid sheet, and improving production efficiency

Method used

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  • Calibration method of a detector and device and equipment using the calibration method
  • Calibration method of a detector and device and equipment using the calibration method
  • Calibration method of a detector and device and equipment using the calibration method

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Embodiment 1

[0034] A detector calibration method, comprising the following two steps: step 1 is to obtain the occlusion ratio of the detector by measuring the inclination angle of the grid sheet or using different focal points of the CT machine, and step 2 is to use the occlusion ratio to defocus Correction (off-focal correction).

[0035] Step 1 is to use the different focal points provided by the CT machine, and the occlusion ratio can be directly calculated from the raw data of the CT machine. For example, use the two focal spots of Flying focal spots or the large and small focal spots of a single focal spot. Due to the slight deviation of the positions of the two focal points, the detector response under the two focal points is divided, such as formula 1, and the detector channel with a jump can be found. The grid sheets of these channels are installed with a slope, and the sign reflects the direction of the slope of the grid sheet.

[0036] Formula 1: Ratio=(A 1 / A 2 -1)

[0037...

Embodiment 2

[0048] In step 1 of this embodiment, the occlusion ratio is calculated by using the large and small focal points of the single focal point, and other contents are the same as in the first embodiment. The calculation of intermediate results and correction effects is consistent with that of Example 1.

Embodiment 3

[0050] In step 1 of this embodiment, the inclination angle of the grid sheet is obtained by measuring the angle with an instrument, and then the shading ratio is calculated. Other content is the same as embodiment 1.

[0051] Such as image 3 As shown, using an angle instrument to measure the inclination angles α and β of the grid sheets on both sides of each detector, the shading ratio of the detector can be calculated by formula 3:

[0052] Ratio=(L*tanα+L*tanβ) / Width (Formula 3)

[0053] Among them, L is the height of the grid sheet, and Width is the width of the detector. The inclination angles α, β of the grid sheet can also be calculated by x1, x2 and the height L of the grid sheet.

[0054] as attached Figure 8 Shown is the distribution of occlusion ratios measured by angle instruments. The typical convolution kernel changes obtained according to this angular distribution are shown in the attached Figure 9 As shown, the images before and after correction are sho...

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Abstract

The invention relates to a correction method of a detector, and a device and equipment using the correction method. The correction method comprises the following two steps of (1) calculating through measuring an inclination angle of a grid piece or utilizing different focuses of a CT machine, and obtaining a shielding proportion of the detector; (2) utilizing the shielding proportion to carry out defocusing correction. According to the method, the phenomena of re-disassembly and re-installation due to arc-shaped or strip-shaped artifact generated on an image caused by the inclination of the grid piece can be effectively avoided, so that an inclination angle of the grid piece can be quickly and conveniently detected, image correction is realized, and the occurrence of the artifact is avoided.

Description

technical field [0001] The invention relates to a method for calibrating optical components used in CT equipment, and in particular provides a method for calibrating a detector and a device and equipment using the method. Background technique [0002] CT machine mainly includes X-ray tube and detector system, as attached figure 1 As shown, they are used to transmit and receive X-rays respectively. For a CT machine, X-rays that are transmitted in a straight line are used for imaging, so it is necessary to suppress the X-rays that change the direction of transmission. These X-rays that change the direction of transmission are scattered X-rays. Scattered X-rays mainly include two types: one is inherent in the CT machine itself, that is, the scattering in the X-ray tube, also called off-focal radiation, and the other is One is scattering associated with imaging the sample. No matter what kind of scattering, anti-scattering grid (Anti-scattering grid, ASG) can be used to suppr...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): A61B6/03
Inventor 刘炎炎
Owner SHANGHAI UNITED IMAGING HEALTHCARE