Overview
Tone mapping compresses bright and dark image values so rendered or captured HDR content fits a standard display while retaining useful contrast.
CoreSource checked
Tone Mapping
Maps high-dynamic-range color values into a displayable range.
Quick Facts
Compact metadata for implementation and discovery.
- Category
- Rendering
- Difficulty
- Intermediate
- Family
- Image Formation
- Tier
- Core
- Status
- Verified
- Review
- Source Checked
- Sources
- 1
- Formulas
- 1
- Relationships
- 1
- Code example
- Ready
- Visualization
- Ready
Core Concepts
dynamic range compressionexposuredisplay transformcolor mapping
Quick facts
Complexity
Runtime and memory behavior at a glance.
Best
O(pixels)
Average
O(pixels)
Worst
O(pixels)
Space
O(1)
When to Use
- Use when real-time graphics needs dynamic range compression.
- Use when the input matches the assumptions behind image Formation.
When Not to Use
- Avoid when the effect costs more than the visual improvement for the target hardware.
- Avoid when a simpler algorithm gives the required result with less setup.
What It Does
- Maps high-dynamic-range color values into a displayable range
- Uses dynamic range compression and exposure to guide the work.
- Produces rendered image.
Use Cases
- Real-time graphics
- Offline rendering
- Lighting and visibility effects
Inputs
- Scene geometry
- Materials
- Camera and lighting state
Outputs
- Rendered image
- Visibility or shading buffers
Key Formulas (1)
Reinhard tone map
colorout = colorin / (1 + colorin)
color_out = color_in / (1 + color_in)Compresses high values into a displayable range.
Pseudocode
- 1.Prepare the inputs and state needed for Tone Mapping.
- 2.Apply the dynamic range compression step while the stopping condition has not been met.
- 3.Update intermediate state and discard invalid candidates.
- 4.Return rendered image.
Canonical Example
- Input
- Tone Mapping input
- Output
- Rendered image
- Explanation
- Tone Mapping applies dynamic range compression to produce rendered image.
Implementation Notes
- Keep the data space for positions, normals, and samples explicit in the implementation.
- Keep the dynamic range compression step separate enough to test independently.
Common Pitfalls
- Mixing coordinate spaces or sampling domains leads to artifacts that are hard to debug.
- Test boundary and adversarial cases, not only ideal inputs.
Interactive Mechanism Walkthrough
Spatial Primitive & Sweep-Line CanvasShow rays, samples, buffers, or shading terms that contribute to the final pixel.
Step 1 of 4: Prepare the inputs and state needed for Tone Mapping.
rendering-mechanismNotes
Tone Mapping should be used with the assumptions and tradeoffs of image Formation in mind.
Sources (1)
What each reference supports for this entry.
Reinhard et al. 2002
PaperClassic photographic tone reproduction paper for mapping HDR luminance to display range.
Open sourceExplore Next
Good next jumps from the relationship graph, ranked for useful discovery.
Relationships
View full relationship pageOften paired withPath Tracing
Path-traced images commonly need tone mapping before display.
Related Algorithms
Tags
GraphicsImage ProcessingFilteringVisualization