Re: minor projection measurements?

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Re: minor projection measurements?

Charles P. Daghlian

If you can use a circular selection, these macros (first one taken from Wayne)
will count the number of rays crossing the selection. Be sure to mak the image
binary first. You could easily modify this to use the various line selection
tools and then make use of the get.Profile  command.

var xcenter, ycenter, radius, steps; //global variables

  macro "Circular Selection Tool -C00b-B11-O11cc-F6622" {
        getCursorLoc(x, y, z, flags);
        xcenter = x; ycenter = y;
        getBoundingRect(x2, y2, w, h)
        if (selectionType==1 && x>x2-4 && x<x2+w+4 && y>y2-4 && y<y2+h+4)
            move(w, h);
            create(xcenter, ycenter);

    // move existing circular selection until mouse released
    function move(width, height) {
        x2=-1; y2=-1;
        while (true) {
            getCursorLoc(x, y, z, flags);
            if (flags==0) return;
            if (x!=x2 || y!=y2)
                makeOval(x-width/2, y-height/2, width, height);
            x2=x; y2=y;

    // draw circular selections until mouse released
    function create(xcenter, ycenter) {
       radius2 = -1;
       while (true) {
            getCursorLoc(x, y, z, flags);
            if (flags==0) {
                getBoundingRect(x, y, width, height);
                if (width==0 || height==0)
                    run("Select None");          
            dx = (x - xcenter);
            dy = (y - ycenter);
            radius = sqrt(dx*dx + dy*dy);
            if (radius!=radius2)
                  makeOval(xcenter-radius, ycenter-radius, radius*2, radius*2);
            radius2 = radius;

macro "Plot Circular Selection [p]"{
degrees = getNumber("Angle between points = ?" 4);
steps = 360/degrees;
 values = newArray(steps);
 for (i = 0; i<steps; i++){
   angleInRadians = (6.2832/steps) * i;
   offsetX = cos(angleInRadians) * radius; //radius from circular selection
   offsetY = sin(angleInRadians) * radius;
    x = xcenter + offsetX;
    y = ycenter + offsetY;
    value = getPixel(x,y);
    values[i] = value;
objects = 0;
thisValue = -1;
lastValue = -1;
     for (i=0; i<steps; i++){
          //print(j+"  "+values[j]);
        thisValue = values[i];
        if (thisValue == 255 && lastValue == 0) objects = objects+1;
        lastValue = thisValue;
print(objects+" objects were found");

****Mike wrote:
Hi, Does anyone know if Image J has the ability to measure the number of
projections on the perimeter of an object?

For example, I have created binary images of cells growing on a substrate. Some
are neuronal in shape. I'd like to measure the number of projections (e.g.
axons) emanating from the cell body.

Any suggestions on how to do this?


Mike McIntyre
****End of quote.