Complete contours (outline) from a image

I want to find the contours of (parts) image and sent the output to a laser cutter. For example, take this image:

I use this code:

maskv1 = AlphaChannel[RemoveBackground[bal1]];
contours =
1], "Contours"]; bal4 = ImageGraphics[   ColorNegate[
DeleteSmallComponents[
Dilation[
EdgeDetect[BilateralFilter[Graphics[contours], 7, .1]], .6],
Method -> "Mean"]], ImageSize -> 600];


The output is:

The red line is done by myself. As you can see, the contour is not closed. The desired output is something like:

So I need a function to close the outline/contour. Who has a suggestion to do this?

img = Import["https://i.stack.imgur.com/O14tf.jpg"]

mindisk = BoundingRegion[ImageMesh[RemoveBackground@img], "MinDisk"]

Disk[{56.0259, 59.0719}, 48.1942]

Show[img, Graphics[{FaceForm[], EdgeForm[{Red, Thick}], mindisk}]]