A Comparison of Image Aligning and Correcting Software with an Unmanned Aerial System

Kangsan Lee, Jinwoo Park, Jinmu Choi

gi.star@khu.ac.kr

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Contents

• Introduction

• Data Acquisition

– Image Gathering

– Correcting Lens Distortion

• Image Alignment

– Image Alignment Software

– Comparing Image Stitching Software

– Results

• Conclusion

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Introduction

• Why Unmanned Aerial System: Drone Aircrafts & Satellites: Major role in Remote Sensing Structural problems: Time, Cost and Weather condition UAS, Drone...?

• Purpose of study: Comparing image stitching softwares Variety of softwares in the market Each software was developed ‘On their own needs’

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Q. What is the suitable program for small UAS system?

Data Acquisition

• Image Gathering– Hardware: 3DR Robotics IRIS+(Drone) and GoPro(Camera) are used– Area of interest: Baramarae beach - west coast of South Korea– App. 200 images are collected and used (Flight date: Jan, 2015)

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Figure 1. IRIS+ and GoPro (Right), Mission Planner for autonomous flight (Left)

Data Acquisition

• Correcting Lens Distortion– GoPro(small digital camera) has a lens distortion (Tauro et al., 2014)

– Adobe Lightroom is selected to remove lens distortion

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Figure 2. Lens distortion correction (before – later)

Image Alignment

• Experimental Design

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Component Specification

CPU Intel Xeon CPU E3-1231 3.40GHz

RAM 16GB (DDR3, Dual Channel)

GPU GeForce GTX 750Ti

Cuda Core 640

Storage SSD, 256GB

Table 1. Specification of the testing environment

Computing EnvironmentProcessing

TimeTotal Image

Volume

Image Qual-ity

Image Alignment

• Image Alignment Software– Five major software are selected to test about stitching performance– Open-Source software(GPL); Hugin– Commercial software; Photoscan, Photoshop, MS ICE, Pix4D

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Name Developer License Notes

Photoscan Agisoft Proprietary Using photometry method

Photoshop Adobe Proprietary User-friendly interface

Image CompositeEditor

Microsoft Proprietary(Free for non-commercial use)

Variety of pre-defined projection

Hugin Pablo d'Angelo et al.

GPL Based on panorama tools

Pix4Dmapper Pix4D SA Proprietary Optimized for UAS

Table 2. Software information

Image Alignment

• Comparing image stitching software– The amount of input data has been changed; range from 50 to 200

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Figure 3. Concept of software comparing experiment

Image Alignment

Results

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1) Processing Time• Gradually increased• MS ICE → Fastest• Hugin → X working: Software limitation• Photoshop → X working 150↑: Hardware limitation

Image Alignment

2) Image Volume• Image volume gradually increased according to numbers of images• MS ICE exports the lowest volume• Photoscan shows the highest rate of increase

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Image Alignment

3) Image Quality

• Photoscan shows the best quality without any problem

• MS ICE and Photoshop have some distorted

• Pix4D cannot calibrate colour and image matching

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Conclusion

• Limitation– Researchers can easily find alternative Open-Source software– But the performance of open-source software does not reach to com-

mercial one

• Potential– The potential of open-source software is sufficient– E.g. Visual SFM became the best 3D image reconstruction open-source

software

• Future Market– The sales market of UAS(Drone) have been increased– Needs of image stitching will be increased in the near future

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Thank you