AI-900 Practice Question: Describe features of computer vision workloads on Azure
A retail company wants to build a system that can verify the identity of customers by comparing their live photo with an uploaded government-issued ID photo. Which Azure Computer Vision service should they use to perform the face comparison?
⚠ Common exam trap
Many exam-takers confuse the general-purpose Azure Computer Vision - Image Analysis service with the specialized Face API, assuming that any computer vision service can perform face comparison, when in fact only the Face API provides dedicated face verification functionality.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Azure Face API
The Azure Face API is specifically designed for face detection, verification, and comparison tasks. It can compare a live photo against a reference photo (such as a government-issued ID) using its 'Verify' operation, which returns a confidence score indicating whether the two faces belong to the same person. This makes it the correct choice for identity verification scenarios.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Azure Computer Vision - Image Analysis
Why it's wrong here
Azure Computer Vision - Image Analysis is a general-purpose visual understanding service. It can detect faces in an image and return attributes like age, emotion, or whether a person is wearing glasses, but it does not create an identity signature or compare two separate face images to determine whether they belong to the same person. Therefore, it lacks the core 1:1 face verification capability required here.
When this WOULD be correct
A company wants to automatically generate captions for product images and detect common objects like 'car' or 'tree' in photos. In that scenario, Azure Computer Vision - Image Analysis would be the correct service because it provides image description and object detection features.
- ✓
Azure Face API
Why this is correct
Azure Face API is the correct choice because it provides a dedicated face verification endpoint that performs 1:1 matching. The service detects facial landmarks in a live photo, extracts a unique face embedding, and compares it against a reference photo (such as an ID document) to compute a similarity score against a configurable confidence threshold. This is precisely the identity-verification scenario the retail company needs.
- ✗
Azure Custom Vision
Why it's wrong here
Azure Custom Vision is a model training service for building custom image classifiers or object detectors from your own labeled datasets. While you could theoretically train a model to recognize a specific person's face, it does not offer a prebuilt, turnkey face verification endpoint with facial landmark detection, similarity scoring, and confidence thresholds. It also requires extensive training data and management, making it unsuitable for out-of-the-box identity verification against an ID photo.
When this WOULD be correct
A company needs to build a custom model to identify specific animal species in wildlife camera images, where no pre-built service exists. Azure Custom Vision would be correct because it allows training a tailored image classifier with their own labeled dataset.
- ✗
Azure Form Recognizer
Why it's wrong here
Azure Form Recognizer is a document intelligence service that extracts text, tables, and key-value pairs from forms and documents using OCR and layout analysis. It processes document structure and printed or handwritten content but does not analyze facial features or compare images of people. Hence, it is completely unrelated to the face verification requirement.
When this WOULD be correct
A company needs to automatically extract data (e.g., name, ID number, expiration date) from scanned government-issued IDs and then validate that data against a database. In that case, Form Recognizer would be the correct service for document data extraction.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The AI-900 exam frequently reuses these exact scenarios with slightly different constraints.
✓Azure Face APICorrect answer▾
Why this is correct
Azure Face API is the correct choice because it provides a dedicated face verification endpoint that performs 1:1 matching. The service detects facial landmarks in a live photo, extracts a unique face embedding, and compares it against a reference photo (such as an ID document) to compute a similarity score against a configurable confidence threshold. This is precisely the identity-verification scenario the retail company needs.
✗Azure Computer Vision - Image AnalysisWrong answer — click to see why▾
Why this is wrong here
Azure Computer Vision - Image Analysis can extract tags, descriptions, and objects from images, but it does not provide face comparison or verification capabilities. The question specifically requires comparing a live photo with an ID photo, which is a face verification task that only the Face API supports.
★ When this WOULD be the correct answer
A company wants to automatically generate captions for product images and detect common objects like 'car' or 'tree' in photos. In that scenario, Azure Computer Vision - Image Analysis would be the correct service because it provides image description and object detection features.
Why candidates choose this
Candidates may assume that 'Computer Vision' encompasses all vision tasks, including face comparison, because the service name sounds comprehensive. They might not realize that face-specific operations are delegated to a separate dedicated service (Face API).
✗Azure Custom VisionWrong answer — click to see why▾
Why this is wrong here
Azure Custom Vision is designed for training custom image classification or object detection models, not for pre-built face verification tasks like comparing a live photo to an ID photo. The question requires a ready-to-use face comparison service, which Custom Vision does not provide out of the box.
★ When this WOULD be the correct answer
A company needs to build a custom model to identify specific animal species in wildlife camera images, where no pre-built service exists. Azure Custom Vision would be correct because it allows training a tailored image classifier with their own labeled dataset.
Why candidates choose this
Candidates may think 'Custom Vision' can be adapted for any image task, including face comparison, overlooking that Azure already offers a dedicated, pre-built Face API for such scenarios.
✗Azure Form RecognizerWrong answer — click to see why▾
Why this is wrong here
Azure Form Recognizer is designed to extract text and structure from documents (e.g., forms, invoices), not to compare faces or verify identity against a photo.
★ When this WOULD be the correct answer
A company needs to automatically extract data (e.g., name, ID number, expiration date) from scanned government-issued IDs and then validate that data against a database. In that case, Form Recognizer would be the correct service for document data extraction.
Why candidates choose this
Candidates may mistakenly think Form Recognizer can handle ID verification because it processes ID documents, but it lacks facial comparison capabilities.
Analysis generated from the official AI-900blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Go deeper
Related to this question
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Azure Machine Learning Studio
Key term
Confidence score
A confidence score is a number (often between 0 and 1 or 0 and 100%) that tells you how likely it is that an AI model's prediction or answer is correct.
Key term
Service
A service is a software component or system that performs a specific function and is available to be used by other programs or users over a network.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This AI-900 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the AI-900 exam.