AST Digital Magazine July 2017 Digital-July | Page 24

Volume 14 The purpose of the mesh face-mask is to simu- late some of the issues associated with H.264 and H.265 image compression. It is not a perfect analogy, but the mask does a respectable job of damaging fine details and mucking up clean lines between colors. Have your clients wear both the sunglasses and the face-mask at the same time while performing the exercise. They may look like a Martian, but they will be gaining valuable information... like NASA astro- nauts training for a mission. If they choose not to wear the sunglasses and mesh face-mask, make sure they know the ob- served detail and clarity for each measured PPF will be better than what security cameras can de- liver. When they are not wearing the sunglasses and face-mask, the results will be more a recording made with a high-end camcorder or DSLR cam- era. Security cameras have to make compromises to keep their prices down and to efficiently utilize hard-drive space. High-end camcorders and DSLRs do not have to make such compromises. Laser Range-Finder? Many hunters, golfers and outdoor enthusiasts already own a laser range-finder. They certainly make measuring distances fast and easy. This is the laser range-finder I use. If you do not have access to one of these, additional measur- ing options are discussed below. July 2017 Edition Why the cheetah? One of the props I use is a lifelike cheetah. I chose it because as the resolution becomes less and less, the cheetah starts to look more and more like a dog. This seems to help some people recognize the significant contribution of image detail during an incident investigation. If they aren’t capturing enough detail to recog- nize one species from another, how are they ever going to distinguish one human from an- other? Stop Reading... You are done, go try it!! For you over-achievers, here is additional infor- mation you may find useful... The HEED Index has nothing to do with FoV The HEED Index has nothing to do with a cam- era’s field-of-view (FoV). It is useful for under- standing the amount of detail a person can see compared to the visual acuity terms describing it. In other words, the HEED Index is a point-to- point tool useful in describing the amount of detail you can expect from a properly installed, high-quality surveillance camera. It is not useful for describing the coverage area (square footage or field-of-view) of a particular camera. Increasing camera resolution changes defini- tion? Please note that the distance from the object 24