Help for Vision Autonomous

Our team is currently trying to use Vision for Autonomous but we are now in an issue, we don’t know how to measure the height of an image. We have read a million of pages and we haven’t found any way to do this. If someone knows how to do this PLZ help
The Image: https://drive.google.com/open?id=0By2qiPqkPF-tNWttSnNxbWJnaU0

Are you trying to measure the image itself in pixels? Open it in any editing software. (paint, GIMP etc.) The image is 102 px wide by 66 px high.
If you are trying to see how high each of the outlines are, you want to know what you are looking at. Assuming this is the outline of the boiler reflective tape, the lower one is 2" tall and the upper one is 4" tall with 4" between them. You need to use math to convert from pixels to real world inches, and it will vary depending on how far you are from the target.

The white lines are the borders of the reflective tape of the boiler, and we want to know the height from the bottom of the image and the height and wide of the shape.

Is this one of the pages you read?
Identifying and processing the targets

The section titled “Measurements” explains the classic formula for turning pixel measurements into real-world units/distance. You need to know the real-world dimensions of your target, the image size of your target (pixels), the camera image size (pixels) and the FOV of the camera (degrees).

You might want to consider using a convex hull algorithm or use bounding rectangles. Then you can get nice polygons and get the vertices. Using those, you can get the specs of the shape in pixels.