Spliced Screen Scheme of Emergency Command Center: Multi-signal Access and Collaborative Display

From heterogeneous signal aggregation architecture, three views of joint business, multi-agent conflict processing, to data freshness alarm and drill acceptance script, "collaboration" is changed from verification list to designable mechanism

The most dangerous thing about the emergency command center is not "not seeing the picture", but "seeing the expired and fake real-time".Frozen screen images, stop watch boards, and meetings that were not prompted after interruption-these may only be experience problems in ordinary monitoring centers, which may lead to wrong decisions in emergency command. The core difference between the emergency command center and the public security and traffic police command center is not in the quantitative level of "more signals", but in three things:Heterogeneous signals converge across network domains, the content seen by local/remote/agents may not be the same during multi-department meetings, and conflicts when multiple agents operate large screens at the same time must be manageable.. These three things will in turn change the aggregation structure, the rules of seating and the way acceptance is done. This article and the public security, traffic police to form a series:Please refer to the public security article for general methodologies such as on-site investigation, reverse of the number of rows and columns on the screen wall, centralized and distributed trade-offs, installation and operation, etc. Please refer to the traffic police article for the conversion of the number of decoded roads, concurrent bandwidth accounting and full load acceptance methods.. This article only expands the emergency-specific "convergence architecture, three views of consultation, agent conflict mechanism, data freshness alarm, multi-room linkage and drill acceptance script".

1. three working modes: peacetime, wartime, consultation, three sets of display tasks

The display system of the emergency command center does not "always display the same content", but switches with the working state. The signal requirements, operation logic and display layout of the three modes are very different. The scheme design should draw three sets of layout drafts first, and then derive the screen wall scale and signal capacity.

The draft layout of the three modes should be drawn at the proposal stage, rather than "on-site" when it is accepted ". The purpose of the draft layout is to determine "which contents occupy the main screen area, which occupy the auxiliary screen area, and which are previewed in the seats" in each mode, thus deducing the partition design and signal capacity requirements of the screen wall.

Panorama of 2. emergency unique signal sources: more than monitoring and conferencing

The signal source of the emergency command center is much more complicated than that of the ordinary monitoring center. In addition to surveillance video and video conferencing, there are a large number of emergency-specific signals. The scheme design should first make a full list, and then classify it according to "network domain" and "access mode.

Three special requirements for emergency signals

First, multi-channel map transmission is transmitted back at the same time. When the incident is handled, there may be 2-3 drones, multiple groups of individual soldiers, and multiple cloth ball control return pictures at the same time. The plan should confirm: the upper limit of the number of concurrent access channels of the map transmission platform; Processing capacity for simultaneous transcoding of multi-channel map transmission; Whether the bandwidth of satellite link and public network link supports multi-channel simultaneous backhaul; Whether the delay difference between the picture transmission picture and the local monitoring picture displayed on the same screen is acceptable.

Second, multi-sector meetings are connected at the same time. During the joint consultation, the fire, medical, public security, transportation and other departments may be connected to the meeting at the same time. The plan should confirm: the number of concurrent ports of the conference bridge device; Protocol compatibility of conference terminals of different departments (SIP/H.323); During multi-party conference, the local large screen can display several conference pictures at the same time. Who is responsible for audio mixing and echo control.

Third, the readability of high-resolution static images. Satellite remote sensing maps, disaster range maps, and GIS annotation maps are often high-resolution static maps. After the screen is displayed, it is necessary to confirm whether the key annotation is readable when the picture is enlarged to single screen or cross-screen display. The picture refresh method is push or pull; When the static picture and the dynamic video are on the same screen, whether a separate display area is required.

3. heterogeneous signal aggregation architecture: network domain isolation is the premise, unified scheduling is the goal

"Heterogeneous signal convergence" is not to plug all signal lines into the same processor, butNetwork Security IsolationUnder the premise of, let the signals of different network domains realize unified scheduling in the display layer. This is the most underestimated link in the design of the emergency command center.

Five levels of convergence architecture

Network domain isolation: cannot "one line is all connected in"

The emergency command center usually involves multiple network domains: video private network (monitoring), government extranet (business system, GIS), conference private network (video conference), Internet (public opinion, partial image transmission), satellite network (remote area image transmission). These network domains have different security levels and isolation requirements,You can't simply plug all the signal lines into the same processor.。

The correct approach is to complete the access and decoding/collection of signals in each network domain, and "ferry" the signals allowed to be shared to the network domain where the display system is located through security isolation devices (network gates, one-way optical gates, video security access gateways), and then uniformly scheduled by the processor of the display system. The selection and deployment location of isolation equipment shall be determined according to the network security level protection requirements applicable to the project and the regulations of the competent department. The plan shall specify "which signals can cross domains, through which equipment, and whether the signals after cross domains are classified/transcoded".

Access mode: four types of paths are configured separately

Different forms of signals have different ways of accessing the display system, and the corresponding equipment is also different:

• IP video stream (monitoring, partial image transmission): Access through the decoder. The coding format compatibility (H.264/H.265), protocol compatibility (GB/T 28181, ONVIF, RTSP) and concurrent decoding capability of the decoder are the key points of verification. The conversion method of decoding the number of roads refers to the traffic police.
• HDMI/SDI signal (meeting terminal, local computer): Access through the input board of the matrix or processor. It is necessary to confirm the input interface type, resolution support and transmission distance (long distance requires HDBaseT or optical fiber).
• Application screen (GIS, Kanban, business system): The application screen is converted into video signal access through the acquisition workstation or encoder. The acquisition resolution, refresh rate and multi-window acquisition capability shall be confirmed.
• Conference Input Output: The screen output of the conference terminal is connected to the display system, and the local screen is transmitted back to the conference terminal. Confirm the interface type and bidirectional transmission capability of the conference terminal.

4. Federation Business Three Views: Local, Remote, Seats, What Do You See

The joint consultation is the most complex display scenario of the emergency command center. Its core is not "put the picture on the big screen",The content, scope and update logic of the three views of the local screen wall, remote venue and agent preview are different, and must be designed and accepted separately.。

Content differences of three views

Three directions of picture sharing

Local → Remote: The local agent shares the designated screen or screen wall area to the remote conference site. Key verification points: whether the sharing range is controllable (full screen/single window/designated area); Whether the text seen at the remote end after sharing is readable (video conference compression may cause text blurring); Whether the local screen wall is affected during sharing.

Remote → Local: The remote venue screen returns to the local large screen. Key points of verification: the resolution and frame rate of the returned picture; How many can be displayed locally when multiple venues return at the same time; The layout relationship between the returned picture and the local picture (independent window/replacement/picture-in-picture).

Seat → large screen: The agent pushes the preview screen to the designated area of the large screen. Key verification points: response time of push; whether to automatically adjust the layout during push; conflict handling when multiple agents push at the same time (see the next section).

Audio Responsibility Boundary: You can't just talk about images

"Visible but inaudible" is a high-frequency problem in joint business, while audio is often classified as a "conference system matter", resulting in blurred responsibilities between large-screen integrators and conference system manufacturers. A list of audio responsibilities should be specified in the plan:

• Pickup: Who provides the microphone in the local conference room, how large the coverage area is, and whether the pickup partition is supported.
• Echo suppression: Whether the conference terminal or the audio processor is responsible; whether the large-screen sound reinforcement and the conference audio share the sound box.
• Sound reinforcement: Who provides the speaker in the local conference room? Which channel does the remote sound output from.
• Mixing: In a multi-department conference, whether the mixing of multi-party audio is done by the conference bridge device or the local audio processor.

5. multi-agent collaboration: conflict types, processing policies, and operation logs

The emergency command center has a large number of seats and frequent operations. When multiple seats operate large screens at the same time, there must be clear rules for "who can push, push where, and listen to whom in conflict. There are no rules of "coordination", in the actual combat will become "grab the screen".

Permission matrix: three levels of permissions

Conflict Types and Handling Strategies

Multi-agent operation conflicts are not "who is right and who is wrong", but need to preset processing strategies. Common conflict types and handling methods are as follows:

Operation log: tracing "who did what at what time"

The agent operation of the emergency command center shall be marked, and the log shall at least include: operator identity, operation time, operation type (review/screen/layout modification/plan switching), operation object (signal source, window, plan), and operation result (success/failure/adjudicated). The retention period and audit requirements of the log shall be determined in accordance with the equivalent insurance requirements applicable to the project and the regulations of the competent department. The log is not only the basis for retrospection, but also the evidence for judging "who operates first" when dealing with conflicts.

6. data freshness and frozen screen alarm: the most dangerous "false real-time" in emergency scenarios"

This is the key design point that distinguishes the emergency command center from the ordinary monitoring center. The frozen screen of the ordinary monitoring center may only be an experience problem, and the frozen screen of the emergency command center may lead to wrong decisions-the commander thinks he is seeing the real-time scene, but in fact the screen has stopped updating for several minutes.

Three sources of data freshness

Video stream timestamp: The time stamp carried by the camera or platform in the video stream can be extracted by the display system after decoding and compared with the current time. If the timestamp stops updating or the deviation from the current time exceeds a threshold, it is determined as "possible screen freezing".

Platform Heartbeat/Status: Video networking platform for online status monitoring of front-end equipment. When the device is offline or the stream is interrupted, the platform can push the state change, and the display system displays the "signal interruption" mark in the corresponding window accordingly.

Business data timestamp: Data sources (such as weather, hydrology, and emergency resources) usually have a data update time ". The display system or collection terminal shall be able to read the timestamp and display the prompt "Data may expire" when the data exceeds the update cycle and is not refreshed.

Alarm Threshold and Display Mode

Inspection Location and Responsibility Division

Frozen screen detection can be achieved in three locations:Platform side(Video networking platform detects device status and streaming status),Decoding/processing side(the decoder or processor detects the timestamp and frame update of the input stream),Display terminal side(Screen or broadcast control software detection screen update). In the plan, it should be clear which link is responsible for the detection, so as to avoid "all three parties think that the other party is detecting".

For data kanban, expiration detection is more dependentCollection end or business systemProvides a data timestamp. If the business system does not provide a timestamp, the display system cannot determine whether the data has expired-in this case, it should be clear in the scheme that "the business system provides the data update time interface" instead of letting the display system "guess".

7. multi-room linkage: division and routing of the lobby, conference room, decision-making room and duty room

Emergency command center is often not a single room, but "command hall meeting room decision room duty room" multi-room coordination. The core of multi-room linkage is not "all rooms show the same content",Different rooms undertake different tasks, and content division, signal routing and rights management need to be designed separately.。

The technical realization of multi-room linkage usually relies onDistributed architecture or video conferencing/streaming gateway: The pictures in the hall can be pushed to the conference room through the coding node, the pictures in the conference room can be returned to the hall, and the decision room can "read only" the pictures in other rooms without reverse pushing. The plan should be clear: which rooms can push each other, which can only receive one-way, how to manage permissions, and whether the delay of cross-room push is acceptable.

8. Screen Wall and Architecture Matching: Special Considerations for Emergency Scenarios

The general methodology of screen wall row number backstepping, patchwork selection, centralized and distributed trade-offs has been developed in detail in the public security chapter and will not be repeated here. Emergency scenarios require additional attention to three points:

• Multi-room display consistency. If the hall, conference room and decision room all display the same GIS situation or data billboard, the color, brightness and scaling ratio of the screen walls of each room should be as consistent as possible to avoid "the same picture looks different in different rooms". The plan should confirm the brand/model/batch consistency of each room screen and whether it supports uniform color calibration.
• The patchwork sensitivity of the conference room. The conference room is often used for close-up viewing of map annotations and collaborative plotting, and the impact of patchwork on content continuity is more pronounced than in the lobby. The need for close-up viewing should be given priority in the selection of stitching on the screen wall of the conference room. For specific grade judgment, please refer to the special article on stitching.
• Brightness adjustment range. The emergency command center needs to take into account both daytime consultation (bright ambient light) and night duty (dark ambient light). The screen body should support a wide range of brightness adjustment, and the grayscale and uniformity are not seriously degraded in the low light state. Brightness selection method reference brightness feature article.

9. Walkthrough Acceptance Script: Locking the Entire Scenario with a Complete Walkthrough

The "coordination" capability of the emergency command center cannot pass the sub-item demonstration and acceptance. A complete business drill must be used to run the whole process of "event triggering → reading signals → organizing consultation → sharing pictures → abnormal recovery → exiting the plan. The following is a walkthrough script template, which can be adjusted according to the actual project.

10. Quotation Boundary: The Six Most Missed Contingency Items

If the quotation of the emergency command center is only compared with the unit price of the screen body and the processor, the later addition is almost inevitable. The following six items are the most easily missed boundaries in the quotation.

• Safety isolation equipment. Whether the network gate, one-way optical gate, and video security access gateway required for cross-domain convergence are included in the quotation. This part of the equipment is often expensive and needs to be selected according to the requirements of equal insurance.
• Figure transfer platform docking and transcoding. Platform-side interface authorization, transcoding server or multi-channel concurrent access license may be required for docking of unmanned aerial vehicles, individual soldiers and distributed ball control platforms. It should be clear who will bear this part of the workload and costs.
• Conference bridging and audio processing. Conferencing bridge equipment (MCU), audio processor, echo suppression equipment, sound reinforcement equipment required for multi-sector conferences, are included in the quotation. A list of audio responsibilities shall be attached to the offer.
• Multi-room linkage of routing equipment. Encoding nodes, decoding nodes, streaming media servers or distributed nodes required for signal routing between halls, conference rooms and decision rooms are included in the offer.
• Custom development of data freshness alerts. If the business system does not provide a data timestamp interface, you need to customize the development of the collection terminal or docking interface, which is easy to be missed.
• Organization and rectification of drill acceptance. The workload of script preparation, organization and execution, problem rectification and re-inspection of drill acceptance often exceeds the scope of "installation and debugging. The quotation shall specify how many rounds of drill acceptance are included and how the rectification scope is defined.

XI. Common Misunderstandings of Emergency Plan

• Myth 1: Connect all signals directly to the same processor. Signals of different network domains are directly physically connected without security isolation, which violates the security isolation requirements and may be rejected by the security review during acceptance. Cross-domain convergence must be isolated before the signal enters the display system.
• Myth 2: Think that "the picture is still there" is "the data is real-time". The frozen screen and the stop watch look no different from the normal screen, but may have expired for a few minutes. Data freshness alarm must be designed for emergency scenarios, and "real-time with pictures" cannot be defaulted ".
• Myth 3: What you see locally is what you see remotely ". The local screen wall may contain business data that is not suitable for external transmission. You must confirm the sharing scope before sharing it to the remote end. The contents and boundaries of the local, remote and seat views are different and must be designed separately.
• Myth 4: Multi-seat collaboration only depends on "oral agreement". "Listen to the host during the meeting" if there is no technical implementation (permission lock, application/approval process), the screen will still be grabbed in actual combat. The permission matrix and conflict handling policies must be written into the scenario and tested in the walkthrough.
• Myth 5: only discuss the image on the wall, not the audio. "Visible but inaudible" in the federation is a high-frequency problem. The responsibility boundaries of sound pickup, echo suppression, sound reinforcement and sound mixing must be clearly written, and the audio effect must be measured in the drill.
• Myth 6: Multi-room linkage only measures "can you see". The push/return/read-only permissions between the lobby, conference room, and decision room, as well as the layout impact, delay, and bandwidth load during push, all need to be tested in the exercise, instead of just looking at "the picture can come over".
• Myth 7: Exercise acceptance becomes a "sub-demonstration". The drill is divided into several independent links of "watching monitoring", "meeting merchants" and "measuring freezing screen". It is impossible to verify the whole process coordination of "event triggering → review → consultation → sharing → recovery. The walkthrough must run through it and inject exceptions into it.

XII. FAQ

XIII. Conclusion