Graphic Point Finding & Drawing

[piausuk]

Hi, Expert.

I'm now trying to do a project which is image comparison and find out the difference.
For the difference, I would like to draw out i circle to show to the user.

Finding difference

Untitled.jpg (148.96 KiB) Viewed 895 times

The problem i faced was:
* I cannot get & draw out the difference point between both Master image (img1) and SAMPLE image (img2)
* For my result, I would like to draw out the circle based on the MASTER image position in any color inside the Yellow Rectangle (draw by me using paint) for SAMPLE image.

Currently, I have do by overlay technique but not the result i wanted, which is:

Code: Select all

                    ThresholdedDifference filter = new ThresholdedDifference(100);
                    filter.OverlayImage = img2;
                    Bitmap resultImage = filter.Apply(img1);
                    resultImage.MakeTransparent();

                    Bitmap bitmapResult = new Bitmap(img2.Width, img2.Height, img2.PixelFormat);
                    Graphics g = Graphics.FromImage(bitmapResult);
                    g.DrawImage(img2, 0, 0, img1.Width, img1.Height); //background image
                    g.DrawImage(resultImage, 0, 0, img1.Width, img1.Height); //foreground image
                    g.Save();

                    pictureBox2.Image = bitmapResult;


result of finding

Untitled2.jpg (147.29 KiB) Viewed 895 times

* This is trying to overlay the SAMPLE image by using the difference of both image.
* The result will be in the Yellow Rectangle(draw by paint) of SAMPLE image(img2).
* If possible, I would like to change the differences color (inside the SAMPLE image - white color) during the .MakeTransparent() method into other color so that it will directly so the different. (for me, this is the most simplest way to do the comparison.)

At last, thanks for you view and if possible, please guide me or given me any suggestion to do that... ^.^

[andrew.kirillov]

Hello,

If you need to draw something on an image, you may use standard .NET class - Graphics. Just use Graphics.FromImage() and then draw with it.

[piausuk]

Dear Andrew,

Thanks for you suggestion, but the thing is how can i store the position of the differences for both image in order to use for drawing?

PS

[andrew.kirillov]

Well, if you can build AForge.Imaging.dll from current sources in trunk, you will find there a new method, which is UnmanagedImage.CollectActivePixels() - collects coordinates of none black pixels in the image. Otherwise you will need to wait for release or write similar code on your own.

[piausuk]

Thanks you again, i will try it...

[piausuk]

Hi Andrew,

I have one question regardless the template matching:

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TemplateMatch[] ProcessImage( Bitmap image, Bitmap template, Rectangle searchZone );

Its say the template's image must smaller then the search zone.
what is it mean.

am i wrong, i thought is we specified a search zone by specified a rectangle points and size
then its will compare both image based on the rectangle field.

Thanks

[andrew.kirillov]

Its say the template's image must smaller then the search zone.

Who says? There is nothing about it in documentation. Or you mean exception? Yes, search zone cannot be smaller than template size, because we search for entire template, not its part. Search zone is just an area of source image to search template in (check docs).

BTW. What is the relation of this question to "Graphic Point Finding & Drawing"? Don't need to create single topic and continue posting to it again and again until all your issues are resolved. If you have a new topic to discuss, then start a new topic. But if you wish to continue conversation within the started topic, then fine.

[piausuk]

Dear Andrew,

Ok, thanks, i know what should i do now...

PS