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How can i detect black pixels surrounded by closed white pixels? Background outside shapes should not be considered.

See next two images: First image i would like to extract all black pixels inside the hallow shape because it's traped/surrounded by white, but image 2 have a opeing and in that case i don't need the pixels. Image 3 shows the desired capture area in red

Image 3: Desired capture area from image1 in red. Same pass on image 2 should return 0 pixels (No area detected)

Another example:

Input:

Needed area in red:

EDIT 1:

                Image<Gray, byte> grayscale = ActualLayerImage.ToEmguImage();
                VectorOfVectorOfPoint contours = new VectorOfVectorOfPoint();
                Mat external = new Mat();

                CvInvoke.FindContours(grayscale, contours, external, RetrType.Ccomp, ChainApproxMethod.ChainApproxSimple);

                var arr = external.GetData();
                for (int i = 0; i < contours.Size; i++)
                {
                    if((int)arr.GetValue(0, i, 2) != -1) continue;
                    var r = CvInvoke.BoundingRectangle(contours[i]);
                    CvInvoke.Rectangle(grayscale, r, new MCvScalar(125), 10);
                }

Code on different inputs:

Image 4: OK

Image 5: OK

Image 6: Not OK!

How to discard image6 cases?

EDIT 2: The solution:

                 Image<Gray, byte> grayscale = ActualLayerImage.ToEmguImage();

                VectorOfVectorOfPoint contours = new VectorOfVectorOfPoint();
                Mat external = new Mat();

                CvInvoke.FindContours(grayscale, contours, external, RetrType.Ccomp, ChainApproxMethod.ChainApproxSimple);

                var arr = external.GetData();

                /*
                 * hierarchy[i][0]: the index of the next contour of the same level
                 * hierarchy[i][1]: the index of the previous contour of the same level
                 * hierarchy[i][2]: the index of the first child
                 * hierarchy[i][3]: the index of the parent
                 */
                for (int i = 0; i < contours.Size; i++)
                {
                    if ((int)arr.GetValue(0, i, 2) != -1 || (int)arr.GetValue(0, i, 3) == -1) continue;
                    var r = CvInvoke.BoundingRectangle(contours[i]);
                    CvInvoke.Rectangle(grayscale, r, new MCvScalar(125), 5);
                }

I will try your way, seens the way to go

Join floating white pixels to the nearest island without closing morph? Currently using Closing to gap closing and mergi

Join floating white pixels to the nearest island without closing morph? Currently using Closing to gap closing and mergi

Join floating white pixels to the nearest island without closing morph? Currently using Closing to gap closing and mergi

Join floating white pixels to the nearest island without closing morph? Currently using Closing to gap closing and mergi

Join floating white pixels to the nearest island without closing morph? Currently using Closing to gap closing and mergi

Find a solution, don't know if is the best aproach but this work perfectly CvInvoke.Erode(dst, erode, kernel, anchor, b

But how to create that pattern on image? EDIT: Was able to find a solution, will post it tomorrow

But how to create that pattern on image?

Transform gray image to create a pattern effect on while pixels given a mask I need to create a pattern on white pixels

Transform gray image to create a pattern effect on while pixels given a mask I need to create a pattern on white pixels

Ok it seens my search lot faster: RectSearch: 1ms FindNonZero: 27ms RectSearch: 0ms (When empty) FindNonZero: 2ms (

Ok it seens my search lot faster: RectSearch: 1ms FindNonZero: 27ms RectSearch: 0ms (When empty) FindNonZero: 2ms (

Ok it seens my search lot faster: RectSearch: 1ms FindNonZero: 27ms RectSearch: 0ms (When empty) FindNonZero: 2ms (

Ok it seens my search lot faster: RectSearch: 1ms FindNonZero: 27ms RectSearch: 0ms (When empty) FindNonZero: 2ms (W

Ok it seens my search lot faster: RectSearch: 1ms FindNonZero: 27ms RectSearch: 0ms (When empty) FindNonZero: 2ms (Whe

Language: C# with EmguCV. Will take a look at both, i also updated the code so i search only inside the contour rectangl

Language: C# with EmguCV Will take a look at both, i also updated the code so i search only inside the contour rectangle

Best way to gather all pixels location (XY) inside a closed contour? Currently i have a black&white 3D model sliced

Best way to gather all pixels location (XY) inside a closed contour? Currently i have a black&white 3D model sliced

Best way to gather all pixels location (XY) inside a closed contour? Currently i have a black&white 3D model sliced

Best way to gather all pixels location (XY) inside a closed contour? Currently i have a black&white 3D model sliced

Best way to gather all pixels inside a closed contour? Currently i have a black&white 3D model sliced in 2D images (

Best way to gather all pixels inside a closed contour? Currently i have a black&white 3D model sliced in 2D images (

Detect all black pixels inside a surrounded closed white area How can i detect black pixels surrounded by closed white p

Detect all black pixels inside a surrounded closed white area How can i detect black pixels surrounded by closed white p

Thank you! if ((int)arr.GetValue(0, i, 2) != -1 || (int)arr.GetValue(0, i, 3) == -1) continue; // Solved my problem :)

Thank you! if ((int)arr.GetValue(0, i, 2) != -1 || (int)arr.GetValue(0, i, 3) == -1) continue; // Solved my problem :)

Thank you! if ((int)arr.GetValue(0, i, 2) != -1 || (int)arr.GetValue(0, i, 3) == -1) continue; // Solved my problem :)

Thank you! if ((int)arr.GetValue(0, i, 2) != -1 || (int)arr.GetValue(0, i, 3) == -1) continue; // Solved my problem :)

Detect all black pixels inside a surrounded closed white area How can i detect black pixels surrounded by closed white p

That almost solved the problem, but when shape is all solid it get returned. I have edited my post to show the problem.

Detect all black pixels inside a surrounded closed white area How can i detect black pixels surrounded by closed white p

Detect all black pixels inside a surrounded closed white area How can i detect black pixels surrounded by closed white p

Detect all black pixels inside a surrounded closed white area How can i detect black pixels surrounded by closed white p

Detect all black pixels inside a surrounded closed white area How can i detect black pixels surrounded by closed white p

No, i've add the desired capture area on main post. Also the shape is an example, but they can by any shape and odd form

Detect all black pixels inside a surrounded closed white area How can i detect black pixels surrounded by closed white p

No, i've add the desired capture area on main post. Also the shape is an example, but they can by any shape and odd form

No, i've add the desired capture area on main post. Also the shape is an example, they can have any shape and odd forms

Detect all black pixels inside a surrounded closed white area How can i detect black pixels surrounded by closed white p

Detect all black pixels inside a surrounded closed white area How can i detect black pixels surrounded by closed white p

No, i've add the desired capture area on main post.

Detect all black pixels inside a surrounded closed white area How can i detect black pixels surrounded by closed white p

Detect all black pixels inside a surrounded closed white area How can i detect black pixels surrounded by closed white p