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A Method for Detecting Building Shadows Based on Ghost Images

An image detection and building technology, applied in image analysis, 3D modeling, image data processing, etc., can solve problems such as low overall recognition and incorrect detection of roof shadows

Active Publication Date: 2021-05-25
GUILIN UNIVERSITY OF TECHNOLOGY
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  • Description
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  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The present invention proposes a method for detecting building shadows based on ghost images to solve the problem that the overall recognition degree is not high and roof shadows cannot be detected correctly in previous shadow detection methods

Method used

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  • A Method for Detecting Building Shadows Based on Ghost Images
  • A Method for Detecting Building Shadows Based on Ghost Images
  • A Method for Detecting Building Shadows Based on Ghost Images

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Embodiment example

[0023] In this embodiment, we select an aerial image of a foreign region for occlusion detection processing. The aerial image is taken by RC30 aerial camera, and the adjacent images covering the central city are dv1119 and dv1120, which have a heading overlap of 65%. The buildings in the image are complex and diverse, causing a lot of occlusion.

[0024] In specific implementation, the technical scheme of the present invention can be carried out by means of automatic operation of computer programming.

[0025] The specific operation steps of the ghost image shadow detection program provided by the present invention can refer to the flow chart Figure 4 :

[0026] Step 1, load the image file.

[0027] Convert original and ghost image files to grayscale images for processing. Load a Digital Building Model (DBM) file.

[0028] In this embodiment, the ghost image of the image dv1119 has been generated by the traditional orthorectification method. The loaded ghost image is or...

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Abstract

The invention discloses a method for detecting building shadows based on ghost images, including: 1. Secondary utilization of traditional orthorectification results (ghost images); 2. Finding and correcting a relative error through photogrammetry knowledge analysis Smaller shadow inflection point; 3. Use the coordinates of this shadow inflection point with relatively small error to obtain the sun elevation angle and sun azimuth angle in DBM to detect the ghost image located on the ghost roof (the roof obtained by orthorectification correction) and the ground The shadows on the , and finally through the layer overlay to display the complete shadow detection results. Using the invention to detect building shadows can effectively avoid the problem of being unable to detect the boundaries of shadow areas projected on roofs in previous methods, thereby increasing the detection rate on roofs by 33.33%. The invention has simple operation, improves the speed of shadow detection and saves detection cost.

Description

technical field [0001] The invention belongs to the field of aerial photogrammetry, and relates to a method for detecting building shadows based on ghost images, in particular to the accurate determination of the sun elevation angle, sun azimuth angle and the shadow area of ​​the building roof, so that the ghost image can reach The effect of real orthophotos. Background technique [0002] The image obtained after traditional orthorectification processing does not fully take into account the geographical information of the building shadow, which makes the spatial object in the shadow area deviate from its original position, and makes the building shadow greatly affect the accuracy of the orthophoto and availability. Therefore, in order to improve the quality of corrected images, shadow detection becomes a necessary link in the process of orthophoto correction. [0003] Previous model-based shadow detection methods mainly establish shadow statistical models based on the prop...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06T7/507G06T7/70G06T17/05
CPCG06T17/05G06T7/507G06T7/70
Inventor 周国清沙洪俊
Owner GUILIN UNIVERSITY OF TECHNOLOGY
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