By: Paul Chivers
Question: What should I use as a proper scale?
Answer: It is essential to include some type of scaling device in photographs for fragmentation analysis. It's recommended to use any solid scaling device with a contrasting color to the material which can be laid down flat on the material in question. White is usually a good choice.
Range rods, yard/meter sticks and customized frames can all be used. We discourage the use of balls as they can expand and contract with changes in temperature and altitude. Be sure to position the scaling device horizontally in your image.
When there is a significant slope to the material you should use two scaling devices placed horizontally, one in the foreground and the other higher up the slope. WipFrag can utilize the two scales to apply perspective correction compensating for the slope of the material.
WipWare also offers the WLS-30 Light Scale, which projects a pair of green laser dots a fixed distance apart onto the material. This scaling method avoids the need to climb over the material to position and retrieve scaling devices. If tilt correction is required when using a Light Scale, the lasers should be re-calibrated to aim high in the field of view and combined with a physical scale placed in the foreground.Tweet