gray2rgb — Convert grayscale images to RGB in MATLAB and RunMat.
gray2rgb(I) replicates an M-by-N grayscale image across red, green, and blue channels to produce M-by-N-by-3 truecolor output. Type handling and shape behavior follow MATLAB semantics.
Syntax
RGB = gray2rgb(I)Inputs
| Name | Type | Required | Default | Description |
|---|---|---|---|---|
I | Any | Yes | — | Grayscale input image. |
Returns
| Name | Type | Description |
|---|---|---|
RGB | NumericArray | RGB image with replicated grayscale channels. |
Errors
| Identifier | When | Message |
|---|---|---|
RunMat:gray2rgb:TooManyInputs | More than one input argument is supplied. | gray2rgb: too many input arguments |
RunMat:gray2rgb:InvalidInput | Input cannot be interpreted as an MxN grayscale image. | gray2rgb: invalid input |
RunMat:gray2rgb:Internal | RGB output tensor construction fails internally. | gray2rgb: internal conversion failure |
How gray2rgb works
- Accepts MxN grayscale images.
- Preserves host tensor dtype metadata.
Example
Replicate Gray To RGB
RGB = gray2rgb(I);Expected output:
% RGB is MxNx3Using gray2rgb with coding agents
Open a RunMat example with live inputs, then ask the agent to explain how gray2rgb changes the result.
Run a small gray2rgb 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 gray2rgb is executed, line by line, in Rust.
- View the source for gray2rgb 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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