How much do you want freezer cases and shelves to know about you? All a retailer needs is a camera and specialized software to gather key information about who you are and how you react to its products. Someone out there is interested in how you react to everything… even mundane frozen food.

I spent a day wandering the aisles of the National Retail Federation’s Big Show, an industry conference for, well, the retail industry. Vendors where there offering everything a retailer could need from complex e-commerce software and analytics to paper bags. One trend in physical stores is to watch you, the customer, and tailor your experience accordingly.

Here, for example, is a freezer case with two features that probably aren’t yet at your local grocery store. What you’ll notice is that the glass is a screen, catching your attention with breakfast pizza bagel animations and other promotions. It’s also a touchscreen, letting customers learn more about the products within without opening the door.

What the shopper probably doesn’t notice is the camera at the top, which is watching you. In this case, it analyzes shoppers’ faces to tally up how many of each gender passed by, and their facial expressions when looking at the product. (If this data was live from the camera at the conference, which I don’t think it was, Kraft was handing out free cheese in front of the case, so that would account for the smiles.)

The data on the other end of these systems can be quite complex, but here’s a very simple version that mega-food-company Kraft Heinz had on display.

This technology could be used for more than keeping score: you could also, for example, change the promotions or what information you push to someone as they walk by.

I missed this display, where shelves update in real time and push promotions based on the age and gender of the person it sees on camera.