Surveillance Video Analysis Case Study

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Video Transcript

This case involved a woman going into a school after hours and recording a private conversation.

She went into this reception area and the reception area is normally locked after school hours, and she was able to sneak into the reception area after someone had exited. The reception desk was unattended, so she was just standing there by herself, and then she heard a conversation coming from the superintendent's office, which is in a hallway coming off of the reception area. She walked over to the hallway and recorded the conversation because she was in a private area recording and conversation. Without getting consent with any of the involved parties, she was charged with criminal trespassing and eavesdropping. A lot of the basis for her charges were the security camera footage of the reception area. Now, the security camera in the reception area has a blind spot where the hallway is. So while you can see her leaving the reception area and going towards the hallway, there's not conclusive video camera evidence that she was actually in the hallway. So her positioning relative the hallway was a very important component of this case. My client approached me with the cell phone footage that she had recorded and the security camera footage, and essentially said, can you triangulate her position and determine whether or not she was actually in this hallway recording this conversation?

We went up to the school where this happened and collected a series of three dimensional scans of the reception area and the hallway extensively photographed, everything documented where the security camera footage was taken from, and the three dimensional scan data allowed us to position the frames from her cell phone video in three dimensional space.

The first step in this was to determine where was her camera in three dimensional space. After answering that question, we'll get into, okay, how was her body positioned? And because we have three dimensional scan data of the hallway and the reception area, and we have this video footage that she was taking, we know that there was 19 seconds where she was outside of the line of sight of the security camera footage. We'll look at her camera footage during those 19 seconds and see, okay, she is looking at this specific feature within the hallway. Since we know the parameters of her camera, we're able to position virtual camera within the three dimensional space based on our scan data and determine exactly where her camera is going to be. And we determined that she had positioned her camera beyond the threshold to the hallway. Now, the secondary analysis involves taking a character in three dimensional space scaled to her exact height and weight, and the first question would be, could she have been holding the phone and standing outside the hallway? And then is there evidence that would be putting her within the hallway?

There were two instances in which her phone was in the hallway, and though the first instance, it's likely that she was in the hallway, but we're giving her the benefit of the doubt and saying if she was standing in the reception area and she had been holding her hand out, she could have potentially captured this footage and not been physically in the hallway. Now, the second time she exited the reception area, she's holding her phone such that it is angled upwards at her shoulder. So you can actually see within the video camera footage, you can see her sweatshirt, you can see her hair. So we know that she was standing with her arms crossed with the camera pointing up towards her, and you can conclusively see that her body is in the hallway based on the anatomical landmarks. In addition to the landmarks that are documented within the hallway, working with a visualization team that is extremely competent and able to analyze these to a very high degree of certainty, it's compelling both from an engineering standpoint and that we know that there's a very small margin of error, and just from a visualization standpoint, it looks really good.

A jury can look at this and they're able to conceptualize it. Instead of having someone go up and just describe physics to them, you have something that actually makes sense in three dimensional space.