how to define coordinate of SURF Points?

Hi guys,

I'm now learning about estimating transformation between two images.

I started to learn it from here:

http://www.mathworks.co.jp/products/computer-vision/examples.html?file=/products/demos/shipping/vision/visionrecovertform.html#4

It's really nice actually. I can get this picture, and also I can define the translation, rotation, and its scale.

My question is, is it possible to define the translation of each point?

or at least, can I get the xy-coordinate of each point?

I've tried to read the explanation of detectSURFFeatures from here, http://www.mathworks.co.jp/jp/help/vision/ref/detectsurffeatures.html

Unfortunately, I still don't understand how to define its coordinate.

Can someone teach me about this?

Thank you, Gibran

Answer 1

[Anand]

The SURFPoints object contains a data member called Location, which contains the co-ordinate of the point.

For example, in the original image, the first matched feature is located at

>> matchedOriginal(1).Location

ans =

    139.7482   95.9542

This is matched to the feature in the distorted image located at

>> matchedDistorted(1).Location

ans =

    119.7571  101.1530

I don't understand your question about translation. The distorted image was obtained by rotating and scaling the original image, so there is no translation involved.

Hope this helps.

[Ismail]

Hi, At last I got the locations. Many many thanks.

Ismail

[Afzal wasiullah]

Hi,can i know how to define 119.7571 101.1530 as x-coordinate and y-coordinate

[Sadettin Durmus Talipoglu]

Hi Anand, I have been struggling the same problem. How to define outputs (interest point) of SURF and the other descripters Location ? I am trying to get interest points using canny edge filtered image for input of extractFeatures function. But I can't get location of canny filtered image like detectSURFFeatures output. I hope you can understand my question. Thanks in advance.