AI Engineering/Phase 04/Lesson 26

Monocular Depth & Geometry Estimation

A depth map is a single-channel image where each pixel is a distance from the camera. Predicting it from one RGB frame used to be impossible without stereo or LiDAR. In 2026 a frozen ViT encoder plus a lightweight head gets within a few percent of ground truth.

Build + Use 1 hr Python

Prerequisites: Phase 4 Lesson 14 (ViT), Phase 4 Lesson 17 (Self-Supervised Vision), Phase 4 Lesson 07 (U-Net)

#Learning Objectives

Distinguish relative and metric depth and state which one each production model (MiDaS, Marigold, Depth Anything V3, ZoeDepth) solves
Use Depth Anything V3 (DINOv2 backbone) to predict depth for arbitrary single images with no calibration
Explain why monocular depth works at all from a single image (perspective cues, texture gradients, learned priors) and what it cannot recover (absolute scale, occluded geometry)
Lift 2D detections to 3D points using a depth map and pinhole camera intrinsics

Full Access lesson

Keep going. The rest of this lesson is one step away.

Unlock all 503 lessons, video, code, quizzes and every future update. Pay in your own currency with Paystack.

See plans Sign in

The text and code of this lesson are based on AI Engineering from Scratch by Rohit Ghumare, MIT licensed.