G11-2025

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h1. Multi‑Projector System — Project Wiki

h2. Overview

Our goal is to build a two‑projector system that displays seamless still images on a flat screen, where the projected areas overlap and must be blended. Implementation is in Python (OpenCV). Prior to implementation, we document the problem and a viable solution approach.  [[#Scope]]  [[#Work-Packages]]  [[#Team]]

h3. Problem background (why blending matters)

Overlapped regions become over‑illuminated; alpha‑blending with proper masks evens illumination across seams. (See slides: “What is alpha‑blending?”)  [[Alpha‑blending]]  

h2(#Scope). Scope & assumptions

* Start from a *planar* screen with **two** projectors; optical axes *perpendicular* to the screen.

* Work with **still images** first (not video).

* Expected overlapped area is approximately rectangular; target a *linear* drop of mask intensity from 1→0 across the overlap.

* Use Python + OpenCV; iterate from simple to refined.

(From project brief and simplified requirements.) 

h2(#Objectives). Objectives

* Describe the problem and identify a potential solution before coding.

* Apply geometric reasoning (lines/planes in 3D; ray‑plane/ray‑cylinder intersections) as needed.

* Prototype masking that yields smooth, artifact‑free blending.

(From “Objective”, “Skills required”, and problem formulation.)

h2(#Key-Concepts). Key concepts & references

* [[Alpha‑blending]] — concept and examples.

* Forward (screen→projector) and inverse (projector→screen) ray tracing for overlap detection and mask generation.

* “Smooth” masks prevent scratches along mask boundaries.

h2(#Work-Packages). Work packages (WPs)

* *WP1 – Geometry & Calibration*  

  Define screen and projector geometry; set initial positions; document assumptions and coordinate frames. Deliverable: short calibration note and diagram.

* *WP2 – Overlap Detection*  

  Use forward/inverse ray tracing to detect dual‑illumination pixels on the screen. Deliverable: mask preview images for each projector.

* *WP3 – Mask Generation & Blending*  

  Implement linear (then smoothed) alpha masks across the overlap; verify no “scratches” at boundaries. Deliverable: blended still‑image demo.

* *WP4 – Experimentation & Evaluation*  

  Record test setups, parameters, and visual results; checklist for “uniform illumination”.

* *WP5 – Documentation*  

  Maintain this wiki; Doxygen comments in code; weekly log.

h2(#Milestones). Milestones & deliverables

* M1: Geometry & calibration draft (WP1).  

* M2: Overlap detection working on synthetic image (WP2).  

* M3: Smooth masks + blended demo on screen (WP3).  

* M4: Evaluation report + next‑step plan (WP4, WP5).

h2(#Team). Team & roles (click a name to open their profile)

|_. Role |_. Amount |_. Who |

| Advisor | 1 | [[Members/Great-Gilbert-Soco|Great Gilbert Soco]] |

| PL, Project Leader | 1 | [[Members/Koki|Koki]] |

| PM, Project Manager | 1 | [[Members/Noah|Noah]] |

| Redmine – supporter of PM | 1 | [[Members/Nonoka|Nonoka]] |

| Developers | 2–3 | [[Members/Deng|Deng]], [[Members/Great-Gilbert-Soco|Gilbert]] |

| Doxygen Leader | 1 | [[Members/Amirul-Haziq-Bin-Airol-Hairrie|Hachiko (Haziq)]] |

| Doxygen, commenters | 2 | [[Members/Jordan|Jordan]], [[Members/Hazel|Hazel]], [[Members/Sota|Sota]] |

| Wiki Leader | 1 | [[Members/Great-Gilbert-Soco|Gilbert]] |

| Wiki Developers | 2 | [[Members/Zoya|Zoya]], [[Members/Phillip-Anderson|Phillip Anderson]] |

| Jira Research Team | 2 | [[Members/Zack|Zack]], [[Members/Phillip-Anderson|Phillip Anderson]] |

p=. _Tip:_ create each profile page the first time you click a name.  

p=. _Back to top:_ [[#Top|↑]]

h2(#Alpha-blending). Alpha‑blending (notes)

Overlapped areas without masks are brighter; masks weight each projector so the sum equals uniform brightness. Smooth masks eliminate boundary scratches; see examples in the slides.  

h2(#Links). Project links

* Requirements & assumptions: this page, sections [[#Scope]] and [[#Objectives]].  

* Design notes & diagrams: (create) [[Design-Notes]]  

* Experiments log & photos: (create) [[Experiments-Log]]  

* Code repo / file list: (link later)