Start from the shop car park model (free sign-up), or draw your own plan. What a car park's security cameras see depends a great deal on whether they hang on the shop wall or on poles. In this article, on a simulated shop car park, your AI chooses where the cameras go and where they look with suggest_cameras, and checks the placed cameras with get_visibility, using the same tools an AI calls over MCP. Every figure and picture below is their result.
1. What was checked
The simulated shop is 34 × 14 m, with a pavement 2.5 m wide along its front and beyond it a car park of 40 × 30 m (44 stalls, one of them for wheelchair users). Planting runs down both sides, with four trees 5 m tall on each, and the street is to the south (the same model as in the article on how many cars fit).
- What must be seen, and its weight. The car park (weight 1), the pavement along the shop front (2), the pavement at the door (a metre either side of the automatic door, 3) and the car entrance (the cross aisle's last 3 m before the street, and the street pavement across it, 3). The ground is counted on a 0.5 m grid.
- Where cameras may go. The shop's outer walls 3 m up (100 candidates); not inside the shop, nor on the site's edges, where no fence is drawn. Poles are 5 m tall (assumed).
- The camera. 90° across and 60° up and down, seeing 30 m (assumed).
2. The shop wall alone
The AI added one camera at a time where it sees the most, and swapped cameras at the end to see more.
| Cameras | Share seen (weighted) |
|---|---|
| 1 | 54.8% |
| 2 | 79.1% |
| 3 | 85.9% |
| 4 | 87.5% (88.4% after swaps) |
| Place | Seen by the four | Seen by no candidate |
|---|---|---|
| Car park | 90.7% | 8.3% |
| Shop front pavement | 100% | 0% |
| At the door | 100% | 0% |
| Car entrance | 6.1% | 88.9% |
- All four cameras the AI chose are on the shop's front wall.
- What they miss is the strip 2.5 m wide along the street (100 m²) and the car entrance: more than 30 m from the shop wall, out of reach of every candidate on it.
- The figure in the band above the plan is the share of the whole site, including the shop's inside and the street.
3. Two poles at the street
With two poles 5 m tall at the street ends of the planting, west and east, the AI chose six cameras.
| Place | Four on the wall | Six, on the wall and poles |
|---|---|---|
| Car park | 90.7% | 99.7% |
| Shop front pavement | 100% | 100% |
| At the door | 100% | 100% |
| Car entrance | 6.1% | 78.8% |
| In all (weighted) | 88.4% | 98.9% |
- Four of the six are on the shop wall and two on the poles: the west pole's camera looks east along the strip by the street, and the east pole's camera looks down west-north-west over the south-east part of the lot.
- The blind spots left come to 5.5 m², at the west edge of the car entrance, right by the west pole.
- The AI placed the six cameras with one
edit_spacechange and checked them withget_visibility; counted again with the placed cameras, the shares are the same.
4. At the detail to observe a person
Beyond whether a place is seen at all, the AI also counted at the detail at which a person's actions can be made out. The tool's description gives 62.5 px per metre for the "observe" level of IEC 62676-4 (the standard's own text was not checked). A camera 1920 px across with a 90° view has that detail out to 15.36 m.
| Where cameras may go | Cameras | Share seen (weighted) | Car park | Car park seen by no candidate |
|---|---|---|---|---|
| Shop wall | 4 | 42.6% | 36.7% | 58.3% |
| Shop wall and four poles | 8 | 78.1% | 74.3% | 21.4% |
- Besides the two poles at the street, two more were added midway down the planting (south of the third trees). Of the eight cameras the AI chose, four are on the shop wall and four on the middle poles (two on each); it used neither pole at the street.
- 21.4% of the car park is more than 15.36 m from the wall and from every pole, so at this detail no candidate sees it: this is the middle of the lot. To see it this well, put a pole in the lot or use cameras with more pixels.
- With 3840 px across (4K), 62.5 px per metre reach 30.72 m, and the camera's 30 m range limits it first: the six on the wall and the poles at the street see 98.9%, as in section 3.
- The plan draws the placed cameras seeing out to 15.36 m.
5. How to use this, and what it does not know
- No parked cars are drawn. What a car hides is not counted; with the lot full, less is seen than this.
- Seen means in view and in sight. Light at night, glare, and whether a number plate can be read or a face told apart are not calculated; the detail is counted by distance alone.
- Assumptions. The lens (90° × 60°, 30 m), the poles' 5 m and the pixels are assumed. Ask again with your cameras' own figures.
- Put up a notice. The Q&A of Japan's Personal Information Protection Commission (Q1-13) says that a business that uses a security camera to take images in which a person can be identified should specify the purpose as far as it can and use the images only for it. Where people cannot easily tell that a camera is taking their picture, the business should take steps such as a “security camera in operation” notice (Act on the Protection of Personal Information, Article 20(1)).
Tools used
suggest_cameras: chooses where the cameras go and where they look (what must be seen and its weight, where cameras may go, the detail), and counts again what the placed cameras seeedit_space: places the cameras chosen (one change)get_visibility: checks what the placed cameras seeget_view_image: draws what is seen and the blind spots on the plan
