Segmenting a binary image into three parts

Question

I am trying to segment a binary image into three parts, head, body, and tail. The binary image is a stack of tiff files of a moving fruit fly larvae. I was able to do this initially by removing points within a certain distance of the centroid:

However, this broke down when the larvae's head moved too close to the centroid, because the head points would then be removed:

I have been looking for creative solutions to this problem. Trying to fit it to a curved ellipsoid and get the vertice points that make up the tail and the head. However, I have not been very successful! I was curious if anyone had any insight into this problem or a suggestion for a creative solution?

Here are the raw binary images:

1)

2)

Answer 1

The best answer I could manage is to use the following:

1. First I got the vertices using MorphologicalGraph function:

     AbsoluteOptions[MorphologicalGraph[myBinMovie[[frame]]], VertexCoordinates]

2. Sometimes, this would give me more than two vertices so I used an If function to find the furthest two vertices based on the EuclideanDistance function:

      myMaxDisVerts =Table[If[Length@myVertices[[frame, 1, 2]] == 2, 
      myVertices[[frame, 1, 2]],
      myTempMaxDis = 
       Max /@ Table[
         EuclideanDistance[myVertices[[frame, 1, 2, i]], 
          myVertices[[frame, 1, 2, j]]], {i, 1, 
          Length@myVertices[[frame, 1, 2]], 1}, {j, 1, 
          Length@myVertices[[frame, 1, 2]], 1}];
      myVertices[[frame, 1, 2, 
        Flatten@Position[myTempMaxDis, Max[myTempMaxDis]]]]], {frame, 1, 
      Length@myVertices, 1}]

3. Using these points, I then took the closest 70 pixels that were a value of 1 from the Binary image using the ReplacePixelValue function:

    Table[ReplacePixelValue[
       ConstantImage[0, ImageDimensions@myMaskedMovie[[1]]], 
       Flatten[Table[(NearestTo[myMaxDisVerts[[frame, j]], 
             70(*Determines size of head and tail masks*)][
            test6[[frame]]]), {j, 1, Length@myMaxDisVerts[[frame]], 1}], 
         1] -> 1], {frame, 1, Length@myMaxDisVerts, 1}];

4. I then took the centroid of these Binary images that made up the "head" and "tail" of the larvae using ComponentMeasurements and found their closest neighbors through each frame:

    myNearestHTPosCentroid = 
      ComponentMeasurements[#, "Centroid"] & /@ myNearestHTPos;

5. Plotted the centroid and the head and tail points joined points with the original movie:

    myCentroidJoinedLarvaColMovie = 
      Table[Show[myMaskedMovie[[frame]], 
        ListLinePlot[{myCentroidPos[[
           frame]], {myHeadAndTailTracks[[1, frame, 
            2, {2, 3}]]}, {myHeadAndTailTracks[[2, frame, 2, {2, 3}]]}}, 
         PlotMarkers -> {myOrangeCircMark, myCyanCircMark, 
           myRedCircMark}], 
        ListPlot[{Flatten[myCentroidPos[[1 ;; frame]], 1], 
          myHeadAndTailTracks[[1, 1 ;; frame, 2, {2, 3}]], 
          myHeadAndTailTracks[[2, 1 ;; frame, 2, {2, 3}]]}, 
         PlotStyle -> {Lighter[Orange, 0.3], Darker[Cyan, 0.005], Red}, 
         Joined -> True]], {frame, 1, Length@myHeadAndTailTracks[[1]], 
        1}];