Improving Automatic Imaging Algorithms with Dual Camera System
Koskiranta, Tiina (2014)
2014
Tietotekniikan koulutusohjelma
Tieto- ja sähkötekniikan tiedekunta - Faculty of Computing and Electrical Engineering
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Hyväksymispäivämäärä
2014-08-13
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tty-201406271328
https://urn.fi/URN:NBN:fi:tty-201406271328
Tiivistelmä
Mobile camera users trust widely to the automatic camera settings, but the automatic settings do not perform equally well in all situations. All of the automatic settings have their own algorithms, which their operations are based on. Automatic white balance, automatic exposure control and automatic focus are known automatic camera settings.
Dual camera system can improve the automatic settings in mobile cameras. In this thesis dual camera algorithms were researched and dual camera algorithm development framework was created. Instead of creating the entire algorithm development framework, the dual camera functionality was added to the existing single camera algorithm development framework. The existing algorithm development framework was a PC application, which could perform the same image processing steps as mobile phone camera image signal processors. The dual camera development framework is able to collect image parameters and markers from one image and provide these to another image. The dual camera development framework manages the parameter mediation by writing and reading XML files.
Few dual camera algorithms were also researched in order to proof the dual camera framework concept. It turned out that the dual camera is able to improve image quality and the automatic camera settings. The automatic exposure control can be improved by collecting additional data from the histogram and by using this information when producing the final image. Motion blur can also be reduced by dual camera algorithm that compares edge data from two distinct images with each other and then provides valuable information about the motion to the exposure control algorithm. The automatic exposure control algorithm can thus reduce exposure time and increase the sensor sensitivity in order to produce sharp images. Automatic white balance can be improved with dual camera system by estimating illumination source with dual camera system.
Even though the dual camera seems to provide some advantages to the algorithms, and the concept that the dual camera development framework introduces, seems valid, addition of second camera to mobile phone should be considered carefully. Many of the dual camera algorithms could be transformed to work with only one camera. The dual camera algorithm development takes also a large amount of time and effort, given that the dual camera is not going to be applied to all future camera phones.
Dual camera system can improve the automatic settings in mobile cameras. In this thesis dual camera algorithms were researched and dual camera algorithm development framework was created. Instead of creating the entire algorithm development framework, the dual camera functionality was added to the existing single camera algorithm development framework. The existing algorithm development framework was a PC application, which could perform the same image processing steps as mobile phone camera image signal processors. The dual camera development framework is able to collect image parameters and markers from one image and provide these to another image. The dual camera development framework manages the parameter mediation by writing and reading XML files.
Few dual camera algorithms were also researched in order to proof the dual camera framework concept. It turned out that the dual camera is able to improve image quality and the automatic camera settings. The automatic exposure control can be improved by collecting additional data from the histogram and by using this information when producing the final image. Motion blur can also be reduced by dual camera algorithm that compares edge data from two distinct images with each other and then provides valuable information about the motion to the exposure control algorithm. The automatic exposure control algorithm can thus reduce exposure time and increase the sensor sensitivity in order to produce sharp images. Automatic white balance can be improved with dual camera system by estimating illumination source with dual camera system.
Even though the dual camera seems to provide some advantages to the algorithms, and the concept that the dual camera development framework introduces, seems valid, addition of second camera to mobile phone should be considered carefully. Many of the dual camera algorithms could be transformed to work with only one camera. The dual camera algorithm development takes also a large amount of time and effort, given that the dual camera is not going to be applied to all future camera phones.