ReCAP for real-time weather map and forecast overlay recognition

Weather segments occupy a sizeable share of Australian commercial television. The nightly news in Sydney, the early-evening bulletin in Melbourne, and the late crossover in Adelaide devote generous minutes to rain radars, animated pressure charts, and forecast overlays. Producers in Brisbane wire tropical cyclone tracks before each broadcast, while Perth newsrooms splice in mining-region dust-storm imagery during winter. Forecast graphics are central to how millions of Australians read the day ahead, and they are unusually hard for automated video systems to interpret. Detecting, labelling, and extracting useful metadata is the specific problem the project/technical workstream of ReCAP was built to address.

ReCAP, an EU-funded research initiative under the Real-time Content Analysis and Processing programme, develops a stack of broadcast-quality video analysis tools. Its modules handle face recognition, logo detection, duplicate-content identification, and quality monitoring across long video assets. The platform's appeal for broadcasters is the speed at which it returns structured information while a live signal is on air. Traditional asset management waits for a recording to end before processing files; ReCAP works on the incoming stream, second by second, classifying what appears, when it appears, and how it behaves over time. That posture is what makes the weather overlay problem tractable, because the answer is rarely a single image.

Forecast graphics across Australian networks draw from shared data feeds, yet the visual presentation varies widely between Channel Nine in Sydney, the ABC in Canberra, Seven in Melbourne, and WIN in regional Queensland. ReCAP's approach is template-aware and overlay-aware rather than pixel-aware. The system treats a moving isobar chart, a colourised rain band, or a wind-arrow overlay as an object with internal structure. That distinction is what the rest of this work hinges on.

Why weather map graphics deserve dedicated attention in news workflows

Generic shot-boundary detection treats a weather segment like any other cut. The system sees a change in frame content, attributes a new summary, and moves on. That is rarely useful for a producer building a retrospective package about the recent Brisbane storm cell, or a compliance officer confirming that a heatwave warning issued in Adelaide actually aired during the 6pm bulletin. Weather graphics carry semantic meaning that goes well beyond a scene change. A forecast overlay is a labelled artefact, often tagged with a Bureau of Meteorology reference, a forecast issue time, and a region identifier. Detecting its presence, identifying which map template is in use, and recording the moment it appeared on screen is the metadata newsroom search tools actually need.

There is a practical workflow reason too. Australian news is heavily templated. Most networks share weather-graphics engines from companies like ChyronHego, Ross Video, or Vizrt, and the same template renders a thousand different maps across a year. If a producer in Hobart is looking for a specific cold-front crossing from last winter, the relevant frames share visual signatures. A system that recognises those signatures can pull every instance in seconds, even when the presenter, the studio lighting, and the lower-third ticker differ completely.

How ReCAP parses animated overlays and template layers

The technical core is a layered detector that separates the camera feed of a presenter from the rendered graphics plane broadcasters composite downstream. ReCAP does not try to read the numbers on a map. Instead, it identifies the visual characteristics of an overlay: the colour palette used for pressure systems, the trajectory lines typical of cyclone tracks, the gradient fills of temperature overlays. From there it classifies the overlay into a small taxonomy of recurring templates, recognising subsequent appearances faster against a learned reference rather than rebuilding the model from scratch.

Animation adds a second layer of difficulty. Forecast overlays are not static slides. Pressure isobars sweep across the screen, rain cells drift, temperature bands pulse, and cities label themselves in sequence. The detector handles this by analysing frame-to-frame deltas within the overlay region and treating sustained motion as confirmation that the graphic is live. Logos and station bugs that sit on top of weather graphics are handled separately, with the network bug and forecast map treated as independent objects.

Australian scenarios where overlay recognition changes the workflow

Cyclone preparation broadcasts along the Queensland coast are a high-pressure case. When a system forms in the Coral Sea and threatens the Townsville-Cairns corridor, networks run multiple bulletins per day, each with an updated track graphic that shifts by a few hundred kilometres. ReCAP can index every appearance of the cyclone track overlay, timestamp the moment a new cone was issued, and surface the corresponding frame in archive search. For a journalist preparing an end-of-season retrospective or an insurance analyst confirming the timeline of warnings, that sequence of metadata is far more valuable than a folder of unknown-length clips.

Heatwave bulletins in Adelaide and Melbourne follow a different rhythm. The graphics are often temperature-shade maps that fade between days, with subtle changes that a viewer would miss but a frame-level detector catches. ReCAP tags the moment the forecast shifts from amber to red, logs the suburbs highlighted, and lets a newsroom search pull every appearance of that warning across multiple bulletins in different states. Bushfire-season maps in regional New South Wales present yet another case, with wind-direction arrows, fire-edge outlines, and total-fire-ban icons layered against terrain.

Routine segments also benefit. A regular 6.45pm Sydney crossing with the same presenter week after week is a stream of recurring graphics, and ReCAP learns the rhythm quickly. After a few weeks the platform can predict, with reasonable accuracy, when the next rain-radar sweep will appear and tag it accordingly. The same consistency principle applies elsewhere too: anyone buying your first laptop learns that reliable detection is the foundation for everything built on top of it.

Quality monitoring during cyclone bulletins and live crossings

Overlay recognition is only useful if the underlying video is usable. Australian broadcasters push live signals through complex chains of compression, satellite uplink, and contribution encoders. A regional feed from Hobart can pass through several encoders before reaching a Sydney playout centre, and each pass can introduce subtle artefacts. ReCAP's quality monitoring module sits on the same stream as the overlay detector and reports on bitrate, resolution, and frame integrity at the same moment an animated overlay is recognised. A cyclone warning broadcast during this pipeline has no margin for failure.

The integration matters because the worst overlay rendering errors tend to appear at the worst moments. Heavy rain at the camera site, a temporary drop in uplink capacity, and a presenter juggling three graphics layers all stress the system simultaneously. ReCAP logs every dip in quality and correlates it with the overlay that was on screen. A producer reviewing a missed warning can see that a band of frames had a quality drop, that the rain-radar overlay was on screen, and that the lower-third regional ticker briefly desynced.

Sports broadcasts, race meetings and rain-delay graphics

Sport is another large source of forecast-overlay-style graphics in Australia. Cricket matches at the MCG and SCG regularly pause for rain, and the on-screen graphics that explain a rain delay are essentially weather overlays rendered over a feed that is not news. The Melbourne Cup carnival at Flemington runs a four-day forecast overlay sequence each morning, with track-rating graphics, wind-direction indicators, and rain probability sliders. AFL matches at Docklands and Adelaide Oval include wind indicators that are miniature forecast graphics in their own right. None of these are traditional newsroom scenes, but each contains a graphical layer that ReCAP's overlay detector handles the same way.

The benefit for sports producers is in archive retrieval and highlight packaging. A documentary producer looking back at the wet 1990s Ashes series can search for rain-delay overlays across dozens of archived broadcasts and pull every relevant frame in minutes. Surf lifesaving broadcasts along the NSW coast, the Ironman events at Port Macquarie, and the Sydney-to-Hobart yacht race start coverage all generate their own classes of overlay, each of which becomes searchable once classified.

Bitrate and resolution consistency in fast-changing scenes

Animated weather graphics are some of the most demanding visual content a broadcaster handles. Frame-to-frame deltas are large, the colour palette changes continuously, and the bitrate required to encode a clean transition is significantly higher than for a talking-head shot. ReCAP's quality monitoring reports resolution and bitrate consistency on a per-frame basis, and weather overlays are among the scenes where the report shows the most variation. For a network engineering team tuning an encoder for the evening news, that data is gold.

A practical walkthrough of how the system handles fast-changing overlays, including resolution dropouts and bitrate spikes during animated temperature sweeps, is documented in resolution and bitrate consistency, a recent post on the project's blog. It is worth reading alongside the technical documentation because it shows what the metrics look like during a real broadcast, complete with animated overlays.

A useful rule of thumb has emerged from the early deployments: a sustained bitrate drop during an animated overlay is rarely a problem with the overlay itself. It is almost always an upstream encoder struggling with the scene complexity, and knowing that distinction saves engineering teams hours of misdirected troubleshooting when a regional bulletin looks soft.

Integration with media asset management and archive retrieval

The long-term value of recognising weather overlays is in archive retrieval. Most Australian broadcasters have decades of news footage indexed only by date, by bulletin, and sometimes by reporter. Adding overlay-aware metadata turns that archive into a searchable resource. A researcher studying how cyclone warnings evolved over thirty years, a climate communication team at the Bureau of Meteorology, or a marketing group at a regional network pulling together a compliance piece can all find what they need.

ReCAP publishes its metadata in standard formats compatible with major media asset management platforms, including those used by Network Ten in Melbourne and Seven in Adelaide. That compatibility means a broadcaster can keep its existing archive infrastructure and still benefit from the overlay-aware fields ReCAP generates. For an Australian broadcaster with a long heritage archive, that non-disruptive integration is the difference between a research project and a production tool.

The next phase of work extends the overlay taxonomy to agricultural forecasts, marine wind charts, and the specialised aviation graphics used in regional pilot briefings. Regional broadcasters in Darwin, Cairns, and the Tasmanian west coast are expected to participate in the next round of demonstrations.

For an Australian newsroom planning a deployment, the practical starting point is small. Pick one bulletin that runs a templated weather segment every weekday, run ReCAP against a month of archived footage, and review how cleanly the system recognises the recurring rain-radar and forecast-temperature overlays. That single test reveals more about the platform's fit than any longer evaluation script. It also surfaces the kinds of templates the broadcaster will want to teach the system in the weeks that follow, and it sets the baseline for the kind of overlay-aware archive the network will carry forward into the next decade of Australian broadcasting.