Microsoft Certified Azure AI Fundamentals · Free Practice Question Medium
Question 2
Which description best captures how a digital color image is represented for processing?
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A
The image is stored as a continuous function that maps pixel coordinates to normalized color values between 0 and 1.
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B
The image is split into three separate grids, each corresponding to red, green, or blue intensities with values typically ranging from 0 to 255.
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C
Every pixel is stored as a hexadecimal string that directly encodes its color.
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D
Each pixel is defined by a single intensity value that is later mapped to a color using an external palette.
Reveal correct answer
Correct answer: B
Explanation
Understanding Digital Color Image Representation
Digital color images are typically represented using the RGB (red, green, blue) color model. This model is fundamental to most image processing tasks, as it provides a straightforward way to encode and manipulate color information on a pixel-by-pixel basis.
How the RGB Model Works
In this representation, an image is divided into three separate matrices or grids, each corresponding to one of the three primary colors: red, green, and blue. Every pixel in the image has three associated values—one for each channel. These values are typically integers ranging from 0 to 255, where 0 indicates the absence of that color component and 255 represents the maximum intensity. By combining these three values, the full color of each pixel is defined, allowing for the accurate reconstruction of the original image.
Why This Representation is Standard
The RGB representation is widely adopted because it aligns with how electronic displays work, where colors are produced by varying the intensity of red, green, and blue light. This method provides a balance between precision and computational efficiency, making it highly effective for digital image processing. It also facilitates a range of operations, such as filtering, segmentation, and color correction, which are essential in computer vision applications.
Why Other Descriptions are Less Suitable
Other descriptions might suggest that an image is stored as a continuous function mapping pixel coordinates to normalized values or as a single intensity value per pixel combined with an external palette, or even as hexadecimal strings. However, these methods either oversimplify the complexity of color representation or do not align with the standard practices used in image processing. The continuous function representation, for instance, is more theoretical and less practical for digital systems, while a single intensity value per pixel is typically associated with grayscale images, not color images. Representing every pixel as a hexadecimal string is not a common processing format due to inefficiencies in mathematical manipulation and storage.
Implementation Considerations
When processing digital images, it is essential to understand the underlying RGB structure. This knowledge enables the development of effective algorithms for tasks such as filtering, edge detection, and object recognition. The standardized 0–255 intensity range allows for consistent operations across various platforms and programming environments, ensuring that image manipulation tasks are both predictable and replicable.
Microsoft Documentation References and Further Readings
A.
This description suggests a continuous model often used in theoretical formulations or certain advanced imaging applications. However, most digital images are discretized into a grid of pixels with integer values (typically 0 to 255). Continuous representations are more abstract and not the standard for practical image storage and processing.
B.
This is the standard representation of a digital color image known as the RGB format. Each pixel is represented by three numerical values indicating the intensity of red, green, and blue. This approach is widely used because it allows independent manipulation of each channel for various image processing tasks.
C.
While hexadecimal notation is a common way to display color values in web development and digital design, it is not the primary internal representation for image processing. Internally, images are typically stored as numerical arrays rather than as strings. Using hexadecimal strings would be less efficient for computational processing.
D.
This describes a paletted or indexed color image, not a true-color image. In indexed images, a palette maps intensity values to colors, but most digital color images use separate channels for red, green, and blue. This method is less common in high-fidelity image processing.
Discussion
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