An Intelligent Vision System (IVS) like Huawei's is designed to provide comprehensive video surveillance and analytics capabilities, integrating various intelligent functions to enhance security and operational efficiency. Based on the typical features of such systems:

• A: Head counting: This is a common intelligent analysis function, often categorized under crowd analysis. It allows the system to count the number of people in a designated area, useful for statistics, crowd control, and retail analytics.
• B: Alarm linkage: IVS platforms are integral to larger security solutions. They support alarm linkage, meaning that upon detecting an event (e.g., intrusion, abnormal behavior), the system can trigger actions in other integrated security components, such as sounding an alarm, activating emergency lighting, or notifying security personnel.
• C: Abnormal behavior detection: This is a core capability of intelligent video analytics. IVS can identify and alert on various predefined abnormal behaviors, such as loitering, fighting, unauthorized entry, or unusual movement patterns, significantly enhancing proactive security.
• D: Automatic alarm reporting: When an intelligent analysis module detects an event that meets alarm criteria, the IVS automatically generates an alarm and reports it to the relevant security center or personnel through various channels, including platform alerts, email, or SMS, ensuring timely response.

All these functions are standard and essential capabilities offered by modern Intelligent Vision Systems.

Optical fiber uses light pulses to transmit data, offering significantly lower attenuation and much greater bandwidth capacity compared to electrical cables. This allows for reliable video and control signal transmission over very long distances, typically dozens to hundreds of kilometers, without the need for repeaters. This makes it the ideal choice for long-distance applications.

Coaxial cables and twisted pair cables, both electrical conductors, suffer from much higher signal attenuation and electromagnetic interference over distance, severely limiting their unrepeated transmission range to a few hundred meters or a few kilometers at most for video signals. Power cables are primarily designed for power delivery and are not suitable for high-bandwidth video and control signal transmission over long distances without specialized and often repeated systems.

Option A is correct: The channel capacity (number of cameras) for both DVRs and NVRs is a specification that varies by model and manufacturer.

Option B is correct: DVRs (Digital Video Recorders) are designed to connect to analog cameras and convert their analog signals to digital for storage. NVRs (Network Video Recorders) connect to IP (network) cameras, receiving already digitized and encoded video streams over a network.

Option C is correct: The primary function of both DVRs and NVRs is to record and store video footage from connected cameras.

Option D is incorrect: While DVRs encode analog video signals into a digital format for storage, NVRs primarily store video streams that have already been encoded by the IP cameras themselves. The NVR typically does not perform the initial encoding for storage; it receives and manages pre-encoded digital streams.

The depth of field (DoF) is the range of distances in front of and behind the main subject that appear acceptably sharp in an image. Several factors influence DoF, including aperture, subject distance, and focal length.

• Focal Length: A longer focal length (telephoto or long-focus lens) inherently results in a shallower depth of field (smaller DoF) compared to shorter focal lengths, assuming the same aperture and subject distance. This is because longer lenses magnify the background blur more significantly.
• Focal Length: Conversely, a shorter focal length (wide-angle lens) inherently provides a greater depth of field (larger DoF). Wide-angle lenses are known for keeping more of the scene, from foreground to background, in acceptable focus.

Therefore, options A and C correctly describe these relationships.

A larger CMOS sensor size generally means that each individual photosite (pixel) on the sensor is larger. Larger photosites have a greater surface area to capture incoming photons. This increased photon collection capability directly translates to higher light sensitivity and better low-light performance, as more signal can be generated from less light. Consequently, a larger CMOS sensor typically exhibits better photosensitive performance, lower noise levels, and improved dynamic range compared to smaller sensors with the same resolution or smaller pixels. Therefore, the statement is true.

Reference: https://www.imaging-resource.com/PRODS/sony-a7s-ii/sony-a7s-iiA.HTM (General principles of sensor size and performance are widely documented across various imaging technology resources)

✅ Option B (Correct)

Reasoning: High Definition (HD) television and video standards typically define 720p as the minimum resolution for an HD signal. A 720p resolution corresponds to 1280x720 pixels. Cameras capable of recording at this resolution or higher are classified as HD cameras.

❌ Why the other choices are incorrect:

• Option A is incorrect: 2048p refers to a horizontal resolution of approximately 2048 pixels, often associated with 2K cinema standards. While it is an HD resolution, it is not the minimum standard for HD.
• Option C is incorrect: 1080p, also known as Full HD, represents a resolution of 1920x1080 pixels. This is a common and higher-quality HD standard, but it is not the minimum HD resolution; 720p precedes it as the entry-level HD standard.
• Option D is incorrect: 560p is a resolution lower than 720p and does not meet the criteria for High Definition (HD) video standards. It would be considered standard definition (SD) or sub-HD.

The statement is TRUE. In camera optics, the focal length of a lens has an inverse relationship with the field of view (FOV). A longer focal length lens (e.g., a telephoto lens) magnifies the subject, bringing distant objects closer, but it achieves this by narrowing the angle of view. This results in a smaller area of the scene being captured, hence a narrower field of view. Conversely, a shorter focal length lens (e.g., a wide-angle lens) captures a broader scene, leading to a wider field of view.

Video security systems employ various storage methods depending on the scale, requirements, and type of cameras (analog vs. IP).

• A: Disk array: These are enterprise-grade storage solutions (e.g., SAN, NAS, RAID systems) commonly used in large-scale surveillance deployments to provide high capacity, redundancy, and centralized management for video archives.
• B: Digital video recorder (DVR): DVRs are fundamental components in traditional analog video surveillance systems, recording video from analog cameras onto internal hard drives.
• C: Cloud storage: Cloud-based storage is an increasingly popular option, particularly for IP camera systems, offering scalability, remote access, disaster recovery, and reduced on-premise hardware requirements (often part of VSaaS offerings).
• D: Network video recorder (NVR): NVRs are specifically designed for IP camera systems, recording digital video streams from IP cameras over a network to internal or external storage devices.

All listed options represent commonly utilized storage methods in modern and legacy video security infrastructures.

✅ Option A (Correct)

Reasoning: Cloud storage provides easy capacity expansion, allowing users to scale storage resources up or down on demand without manual hardware procurement or configuration, ensuring elasticity and meeting evolving needs.

✅ Option B (Correct)

Reasoning: Cloud providers manage the underlying storage infrastructure, including hardware and software maintenance, security, and backups, significantly simplifying management for users and reducing operational overhead.

✅ Option C (Correct)

Reasoning: Cloud storage services are highly customizable on demand, enabling users to provision specific storage types, performance tiers, and data management policies to precisely align with application requirements and budget constraints.

❌ Why the other choices are incorrect:

• Option D is incorrect: Cloud storage typically operates on a pay-as-you-go model, converting capital expenditures (CapEx) to operational costs (OpEx). This, combined with scalability and resource optimization, often makes it more cost-effective than traditional on-premises solutions, especially for variable workloads, rather than inherently high cost.

RAID 1, also known as mirroring, replicates data identically across two or more disks. While it provides high data availability and redundancy, it does not employ a parity mechanism for data verification or reconstruction. If a discrepancy occurs between the mirrored copies, RAID 1 can detect the error but lacks an inherent mathematical method (like parity) to determine the correct data block without external intervention or heuristics.

Why the other choices are incorrect:

• Option A: RAID 5 utilizes distributed parity across all disks. This parity information is used to verify data integrity and reconstruct lost data from a single disk failure.
• Option B: RAID 3 uses byte-level striping with a dedicated parity disk. The parity disk stores checksums that can be used for data verification and reconstruction in case of a single data disk failure.
• Option D: RAID 6 employs dual distributed parity. This means it has two independent parity sets, allowing it to verify data integrity and withstand the failure of up to two disks simultaneously.