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Conclusion of the week.

Like Rebecca Black says; “It’s Friday”. The work week is done, and on Monday there is the second milestone. I will discuss and tell about the techniques I have decided to work with now.

First off I will be using a combination of Fourier Descriptors and Hu Moments to describe my pictures. To use them I will ¬†find contours of my picture and then I will use HuM/FD to describe the contours. Then using the HuM/FD I will compare it to another picture. Comparisons done that way will ignore rotation, translation, skewing, and scaling. Doing comparisons using HuM’s is very easy and can be done fast on already pre processed pictures.

Step by step:

  • Take the picture turn it into greyscale since colour is irrelevant.
  • Find the contours of all shapes in the picture
  • Turn the contours into fourier descriptions and Central Moments, which then is turned into Hu Moments.
  • Compare fourier descriptors and Hu Moments between two pictures.

Compare colour by taking a histogram of picture and by mixing together pixels into bigger groups and compare those. Colour is secondary to shape and will just be a nice extra feature, for slightly better results.

For searching the Hu moments will be used as a low cost comparison, and a general colour of picture as well. I will probably discuss more details about searching the future since right now main focus is to get single picture comparison to work. I still have to figure out how to compare pictures when there is very many shapes in the picture in which order to compare them etc.

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