# Kinect depth image to real world coordinate

Im currently using Kinect xbox 360 with MATLAB software. My current approach to convert depth image to real world coordinate is by using;

X = (j - w/2) * 320/w * M * Z

Y = (i - h/2) * 240/h * M * Z

where,
i = row,
j = column,
w = width of the photo,
h = height of the photo,

M = NUI_CAMERA_DEPTH_IMAGE_TO_SKELETON_MULTIPLIER_320x240 and
Z = distance

what i want to do is to calculate the length in meter of a human shoulder width, so i continue by using the formula

length = X2 - X1.

but still i couldnt get the appropriate answer.. Is my direction correct?