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172 lines
6.9 KiB
Markdown
172 lines
6.9 KiB
Markdown
---
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title: Outpainting
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---
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# :octicons-paintbrush-16: Outpainting
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## Outpainting and outcropping
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Outpainting is a process by which the AI generates parts of the image that are
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outside its original frame. It can be used to fix up images in which the subject
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is off center, or when some detail (often the top of someone's head!) is cut
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off.
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InvokeAI supports two versions of outpainting, one called "outpaint" and the
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other "outcrop." They work slightly differently and each has its advantages and
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drawbacks.
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### Outpainting
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Outpainting is the same as inpainting, except that the painting occurs in the
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regions outside of the original image. To outpaint using the `invoke.py` command
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line script, prepare an image in which the borders to be extended are pure
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black. Add an alpha channel (if there isn't one already), and make the borders
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completely transparent and the interior completely opaque. If you wish to modify
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the interior as well, you may create transparent holes in the transparency
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layer, which `img2img` will paint into as usual.
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Pass the image as the argument to the `-I` switch as you would for regular
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inpainting:
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```bash
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invoke> a stream by a river -I /path/to/transparent_img.png
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```
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You'll likely be delighted by the results.
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### Tips
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1. Do not try to expand the image too much at once. Generally it is best to
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expand the margins in 64-pixel increments. 128 pixels often works, but your
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mileage may vary depending on the nature of the image you are trying to
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outpaint into.
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2. There are a series of switches that can be used to adjust how the inpainting
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algorithm operates. In particular, you can use these to minimize the seam
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that sometimes appears between the original image and the extended part.
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These switches are:
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| switch | default | description |
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| -------------------------- | ------- | ---------------------------------------------------------------------- |
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| `--seam_size SEAM_SIZE ` | `0` | Size of the mask around the seam between original and outpainted image |
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| `--seam_blur SEAM_BLUR` | `0` | The amount to blur the seam inwards |
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| `--seam_strength STRENGTH` | `0.7` | The img2img strength to use when filling the seam |
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| `--seam_steps SEAM_STEPS` | `10` | The number of steps to use to fill the seam. |
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| `--tile_size TILE_SIZE` | `32` | The tile size to use for filling outpaint areas |
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### Outcrop
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The `outcrop` extension gives you a convenient `!fix` postprocessing command
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that allows you to extend a previously-generated image in 64 pixel increments in
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any direction. You can apply the module to any image previously-generated by
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InvokeAI. Note that it works with arbitrary PNG photographs, but not currently
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with JPG or other formats. Outcropping is particularly effective when combined
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with the
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[runwayML custom inpainting model](INPAINTING.md#using-the-runwayml-inpainting-model).
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Consider this image:
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<figure markdown>
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![curly_woman](../assets/outpainting/curly.png)
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</figure>
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Pretty nice, but it's annoying that the top of her head is cut off. She's also a
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bit off center. Let's fix that!
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```bash
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invoke> !fix images/curly.png --outcrop top 128 right 64 bottom 64
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```
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This is saying to apply the `outcrop` extension by extending the top of the
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image by 128 pixels, and the right and bottom of the image by 64 pixels. You can
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use any combination of top|left|right|bottom, and specify any number of pixels
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to extend. You can also abbreviate `--outcrop` to `-c`.
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The result looks like this:
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<figure markdown>
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![curly_woman_outcrop](../assets/outpainting/curly-outcrop-2.png)
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</figure>
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The new image is larger than the original (576x704) because 64 pixels were added
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to the top and right sides. You will need enough VRAM to process an image of
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this size.
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#### Outcropping non-InvokeAI images
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You can outcrop an arbitrary image that was not generated by InvokeAI,
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but your results will vary. The `inpainting-1.5` model is highly
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recommended, but if not feasible, then you may be able to improve the
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output by conditioning the outcropping with a text prompt that
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describes the scene using the `--new_prompt` argument:
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```bash
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invoke> !fix images/vacation.png --outcrop top 128 --new_prompt "family vacation"
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```
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You may also provide a different seed for outcropping to use by passing
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`-S<seed>`. A negative seed will generate a new random seed.
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A number of caveats:
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1. Although you can specify any pixel values, they will be rounded up to the
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nearest multiple of 64. Smaller values are better. Larger extensions are more
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likely to generate artefacts. However, if you wish you can run the !fix
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command repeatedly to cautiously expand the image.
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2. The extension is stochastic, meaning that each time you run it you'll get a
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slightly different result. You can run it repeatedly until you get an image
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you like. Unfortunately `!fix` does not currently respect the `-n`
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(`--iterations`) argument.
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3. Your results will be _much_ better if you use the `inpaint-1.5` model
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released by runwayML and installed by default by `invokeai-configure`.
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This model was trained specifically to harmoniously fill in image gaps. The
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standard model will work as well, but you may notice color discontinuities at
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the border.
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4. When using the `inpaint-1.5` model, you may notice subtle changes to the area
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outside the masked region. This is because the model performs an
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encoding/decoding on the image as a whole. This does not occur with the
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standard model.
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## Outpaint
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The `outpaint` extension does the same thing, but with subtle differences.
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Starting with the same image, here is how we would add an additional 64 pixels
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to the top of the image:
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```bash
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invoke> !fix images/curly.png --out_direction top 64
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```
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(you can abbreviate `--out_direction` as `-D`.
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The result is shown here:
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<figure markdown>
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![curly_woman_outpaint](../assets/outpainting/curly-outpaint.png)
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</figure>
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Although the effect is similar, there are significant differences from
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outcropping:
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- You can only specify one direction to extend at a time.
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- The image is **not** resized. Instead, the image is shifted by the specified
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number of pixels. If you look carefully, you'll see that less of the lady's
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torso is visible in the image.
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- Because the image dimensions remain the same, there's no rounding to multiples
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of 64.
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- Attempting to outpaint larger areas will frequently give rise to ugly ghosting
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effects.
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- For best results, try increasing the step number.
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- If you don't specify a pixel value in `-D`, it will default to half of the
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whole image, which is likely not what you want.
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!!! tip
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Neither `outpaint` nor `outcrop` are perfect, but we continue to tune
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and improve them. If one doesn't work, try the other. You may also
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wish to experiment with other `img2img` arguments, such as `-C`, `-f`
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and `-s`.
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