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Practical Vision Systems · Lesson 16

Capstone: A Parking-Occupancy Prototype

Let us build a practical parking-occupancy prototype.

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Capstone: A Parking-Occupancy Prototype explained visually

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Let us build a practical parking-occupancy prototype. English captions are optional and start off. The complete transcript follows the written lesson.

Lesson overview

What you will learn

Let us build a practical parking-occupancy prototype.

  1. Define the decision
  2. Connect geometry and detections
  3. Evaluate the full system
  4. A worked example
01

Define the decision

Let us build a practical parking-occupancy prototype. The output is a state for each parking space: occupied, empty, or requiring review. Start by annotating the parking regions in a fixed camera view. Define which vehicle position counts as occupying a space and how to handle vehicles between spaces. Those rules determine what the system is supposed to predict.

02

Connect geometry and detections

Next, detect vehicles and connect each detection to the parking geometry. A ground-contact approximation can be more useful than the box center. Tracking may reduce brief fluctuations, but temporal smoothing also delays genuine changes. Measure that delay. If the camera moves, the parking regions may no longer align, so the system needs a way to detect or review that condition.

03

Evaluate the full system

Evaluate complete recording sessions that were not used for development. Include empty spaces, arrivals, departures, occlusion, shadows, and difficult lighting. Report per-space errors and transition timing, not only detector accuracy. Keep a small set of reviewed examples for every important failure type. This project brings together camera geometry, annotations, detection, tracking, and honest evaluation while leaving a clear path for future improvement.

04

A worked example

If a car leaves at ten:zero:zero but smoothing keeps the space marked occupied until ten:zero:five, the system has a five-second transition delay. That may be acceptable for some applications and unacceptable for others. The requirement should be decided before declaring the system successful.

Worked example

If a car leaves at 10:00:00 but smoothing keeps the space marked occupied until 10:00:05, the system has a five-second transition delay. That may be acceptable for some applications and unacceptable for others. The requirement should be decided before declaring the system successful.

Knowledge check

Quick check: test your understanding

Try it yourself: Write a one-page prototype specification with inputs, outputs, occupancy rules, test sessions, error measures, and known limitations.

Check the reasoning

Include a review state and camera-movement handling. Separate detector errors from geometry errors and timing errors so improvements target the actual cause.

Why is detector accuracy alone insufficient for this project?

The final occupancy decision also depends on region geometry, association rules, temporal behavior, and camera stability.

How would you solve the practice case?

Include a review state and camera-movement handling. Separate detector errors from geometry errors and timing errors so improvements target the actual cause.

What does the worked example show?

If a car leaves at 10:00:00 but smoothing keeps the space marked occupied until 10:00:05, the system has a five-second transition delay. That may be acceptable for some applications and unacceptable for others. The requirement should be decided before declaring the system successful.

Further reading

Programming Computer Vision with Python — Jan Erik Solem.

Original ToolsInVision teaching examples. Editorial approach · Suggest a correction

Accessible referenceLesson 16 transcript223 words · Video transcript · Matches the published narration and captionsOpen transcript

Let us build a practical parking-occupancy prototype. The output is a state for each parking space: occupied, empty, or requiring review. Start by annotating the parking regions in a fixed camera view. Define which vehicle position counts as occupying a space and how to handle vehicles between spaces. Those rules determine what the system is supposed to predict.

Next, detect vehicles and connect each detection to the parking geometry. A ground-contact approximation can be more useful than the box center. Tracking may reduce brief fluctuations, but temporal smoothing also delays genuine changes. Measure that delay. If the camera moves, the parking regions may no longer align, so the system needs a way to detect or review that condition.

Evaluate complete recording sessions that were not used for development. Include empty spaces, arrivals, departures, occlusion, shadows, and difficult lighting. Report per-space errors and transition timing, not only detector accuracy. Keep a small set of reviewed examples for every important failure type. This project brings together camera geometry, annotations, detection, tracking, and honest evaluation while leaving a clear path for future improvement.

If a car leaves at ten:zero:zero but smoothing keeps the space marked occupied until ten:zero:five, the system has a five-second transition delay. That may be acceptable for some applications and unacceptable for others. The requirement should be decided before declaring the system successful.