ind2rgb — Convert indexed images and colormaps to RGB in MATLAB and RunMat.
ind2rgb(X, map) maps indexed image values through an N-by-3 colormap to produce truecolor RGB output. Indexing and output-shape behavior follow MATLAB semantics.
Syntax
RGB = ind2rgb(X, map)Inputs
| Name | Type | Required | Default | Description |
|---|---|---|---|---|
X | Any | Yes | — | Indexed image values. |
map | Any | Yes | — | Nx3 colormap. |
Returns
| Name | Type | Description |
|---|---|---|
RGB | NumericArray | RGB truecolor image converted from indexed image and colormap. |
Errors
| Identifier | When | Message |
|---|---|---|
RunMat:ind2rgb:TooManyInputs | More than two input arguments are supplied. | ind2rgb: too many input arguments |
RunMat:ind2rgb:InvalidInput | Inputs cannot be interpreted as numeric indexed image and numeric colormap tensors. | ind2rgb: invalid input |
RunMat:ind2rgb:InvalidColormap | The map argument is not an Nx3 colormap. | ind2rgb: map must be an Nx3 colormap |
RunMat:ind2rgb:InvalidIndex | At least one floating index value is not finite or integral. | ind2rgb: floating index values must be finite integers |
RunMat:ind2rgb:Internal | RGB output tensor construction fails internally. | ind2rgb: internal conversion failure |
How ind2rgb works
- Double and single index arrays use 1-based colormap indices.
- uint8 and uint16 index arrays use zero-based indexed-image values.
- The output appends a third RGB channel dimension.
Example
Indexed Image To RGB
RGB = ind2rgb(X, map);Expected output:
% RGB is size(X) with a third RGB channelUsing ind2rgb with coding agents
Open a RunMat example with live inputs, then ask the agent to explain how ind2rgb changes the result.
Run a small ind2rgb example, explain the result, then change one input and compare the output.
Related Image functions
Open-source implementation
Unlike proprietary runtimes, every RunMat function is open-source. Read exactly how ind2rgb is executed, line by line, in Rust.
- View the source for ind2rgb in Rust on GitHub
- Learn how the RunMat runtime works
- Found a bug? Open an issue with a minimal reproduction.
About RunMat
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