HDR Imaging Techniques & Technologies 2 — Questions and Answers
Question 1: Which tone mapping operator preserves local contrast by processing image regions independently rather than globally?
- Global Reinhard operator
- Local tone mapping operator (Correct answer)
- Gamma correction
- Linear scaling
Correct answer: Local tone mapping operator
Local tone mapping operators analyze and compress dynamic range in spatial regions, preserving fine detail and local contrast better than global methods.
Question 2: What is the primary advantage of using a logarithmic response curve in HDR image sensors?
- Increases color saturation
- Matches human visual system's wide dynamic range perception (Correct answer)
- Reduces noise in highlights
- Improves frame rate
Correct answer: Matches human visual system's wide dynamic range perception
Logarithmic sensors mimic the human eye's response to light, capturing a wide range of luminance values in a way that matches natural perception.
Question 3: In HDR video capture, what does the term 'clipping' refer to?
- Trimming video duration
- Loss of detail when luminance exceeds sensor capacity (Correct answer)
- Applying a color grade
- Reducing bit depth
Correct answer: Loss of detail when luminance exceeds sensor capacity
Clipping occurs when incoming light exceeds the sensor's maximum recordable value, resulting in overexposed highlights with no recoverable detail.
Question 4: Which imaging technology uses multiple exposures captured simultaneously through a beam splitter to achieve HDR in a single frame?
- Rolling shutter
- Global shutter
- Optical beam-splitting multi-sensor (Correct answer)
- Pixel binning
Correct answer: Optical beam-splitting multi-sensor
Optical beam-splitting multi-sensor systems split incoming light and expose multiple sensors at different settings simultaneously, enabling true single-frame HDR.
Question 5: What is 'spatiotemporal' HDR reconstruction in video?
- Using GPS data to anchor color space
- Combining frames across time and space to build HDR sequences (Correct answer)
- Applying temporal anti-aliasing only
- Averaging frames to reduce noise
Correct answer: Combining frames across time and space to build HDR sequences
Spatiotemporal HDR reconstruction merges pixel data from multiple exposures across both spatial location and time to produce high dynamic range video sequences.
Question 6: Which perceptual phenomenon makes HDR images appear more three-dimensional compared to SDR?
- Chromatic aberration
- Luminance-driven depth cues and contrast gradients (Correct answer)
- Reduced color gamut
- Higher frame rate
Correct answer: Luminance-driven depth cues and contrast gradients
Extended luminance range in HDR images enhances natural depth cues such as atmospheric haze and specular highlights, creating a stronger sense of three-dimensionality.
Question 7: What role does 'scene-referred' imaging play in an HDR pipeline?
- It applies output-specific tone mapping early
- It preserves absolute scene luminance values before display rendering (Correct answer)
- It converts images to sRGB immediately
- It limits dynamic range for broadcast
Correct answer: It preserves absolute scene luminance values before display rendering
Scene-referred imaging retains the original, physically accurate luminance of the scene throughout the pipeline, enabling flexible HDR mastering for multiple output targets.
HDR Imaging Techniques & Technologies 2
Which tone mapping operator preserves local contrast by processing image regions independently rather than globally?