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National flag detection method based on single image

A detection method and edge detection algorithm technology, applied in the field of geographic information, can solve problems such as difficult flag detection, lack of pentagram geometric models, etc.

Active Publication Date: 2020-04-10
SUN YAT SEN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In order to overcome the technical defect that the existing single image detection lacks the geometric model of the pentagram and it is difficult to detect the national flag, the present invention provides a national flag detection method based on a single image

Method used

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  • National flag detection method based on single image
  • National flag detection method based on single image

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Embodiment 1

[0044] The invention provides a new two-dimensional equation of the pentagram, and a method for reconstructing the pentagram on the national flag and using the newly established model for deformation and displacement detection. At present, to detect the five-pointed star shape and other geometric characteristics of the five-pointed star of the national flag on the plane of the two-dimensional camera sensor, a rigorous mathematical geometric model that can simultaneously bring in model parameters and all observed values ​​is required. But so far, there is no geometric model of the pentagram.

[0045] More specifically, so far, there has not been a long-distance non-contact measurement method that uses the principle of surveying and mapping remote sensing and is specifically aimed at detecting the national flag. The national flag detection method based on a single image proposed by the present invention, combined with a rigorous mathematical geometric model, enables The flag pen...

Embodiment 2

[0055] More specifically, on the basis of Example 1, the step S1 is specifically:

[0056] Let the center coordinates of the five-pointed star be (X C ,Y C ), Z-axis rotation angle Ψ and radius R 0 , then the parameters satisfy the following conversion equation:

[0057]

[0058] Among them, X' and Y' represent the horizontal axis coordinates and vertical axis coordinates converted into the original position, and R 2D (Ψ) represents the rotation matrix of Ψ;

[0059] Position in the first five divisions is governed by the following constraint equations:

[0060] (X'-R 0 )tan(54°)=|Y'|

[0061] Divide the five-pointed star into ten regions, and the points located in different regions will satisfy the constraints of the constraint equation after being rotated by the angle (p-1) 36°+Ψ, where the parameter p is the ten-region division code, specifically defined as:

[0062]

[0063] Among them, Θ(0°≤Θ≤360°) is the polar angle of the point on the X-Y plane; since the ...

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Abstract

The invention provides a national flag detection method based on a single image. The method comprises the following steps: constructing a pentagram geometric model; extracting an edge point of each five-pointed star from the shot image; extracting five vertexes of the five-pointed star from the edge points of the large five-pointed star; calculating object space coordinates of five vertexes of thelarge star, and correcting the posture and distortion of the camera; coordinate transformation is conducted on the vertex of each five-pointed star, and the center and the angle of each five-pointedstar are calculated; and comparing the calculated center and angle of the five-pointed star with the national flag specification to judge whether the national flag meets the specification or not. Theinvention provides a national flag detection method based on a single image. A pentagram geometric model is constructed on the basis of a pentagon geometric model, pentagram extraction is carried outon a single image shot by a common digital camera, the proportion of a real object is restored, and whether the national flag contains pentagrams which do not conform to specifications or not is accurately judged by utilizing the constructed pentagram-shaped two-dimensional geometric model.

Description

technical field [0001] The present invention relates to the technical field of geographic information, and more specifically, to a national flag detection method based on a single image. Background technique [0002] The detection of the national flag [1] in the hoisting can be realized by using ordinary digital photography. In general, using a common digital camera to take a single image to accurately measure the shape, size, and direction of a target needs to meet some specific conditions, such as pre-determining the position between the camera and the target, knowing the camera’s built-in parameters (interior parameters) in advance, or knowing the camera The sensor plane is completely perpendicular to the target normal, etc. Zhou et al. showed a method of measuring eggs using a single image [2]. In this method, Yuyao placed the eggs on a specific platform and adjusted the position of the eggs to the level. When the light hits the eggs, the shadow can be captured by the c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06T7/00G06T7/60
CPCG06T7/0002G06T7/60G06T2207/30244
Inventor 陈定安刘智泉招倩莹
Owner SUN YAT SEN UNIV
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