SD Webui Vectorscope CC

This is an Extension for the Automatic1111 Webui, which performs a kind of Offset Noise* natively, allowing you to adjust the brightness, contrast, and color of the generations.

Sample Images

How to Use

After installing this Extension, you will see a new section in both txt2img and img2img tabs. Refer to the parameters and sample images below and play around with the values.

Note: Since this modifies the underlying latent noise, the composition may change drastically. Using the Ones scaling seems to reduce the variations.

Parameters

• Enable: Turn on/off this Extension
• Alt: Modify an alternative Tensor instead, causing the effects to be significantly stronger
• Brightness: Adjust the overall brightness of the image
• Contrast: Adjust the overall contrast of the image
• Saturation: Adjust the overall saturation of the image

Color Channels

• Comes with a Color Wheel for visualization
• You can also click and drag on the Color Wheel to select a color directly

Channel	Lower	Higher
R	Cyan	Red
G	Magenta	Green
B	Yellow	Blue

Buttons

• Reset: Reset all settings to the default values
• Randomize: Randomize Brightness, Contrast, Saturation, R, G, B

Style Presets

• Use the Dropdown to select a Style then click Apply Style to apply
• To save a Style, enter a name in the Textbox then click Save Style
• To delete a Style, enter the name in the Textbox then click Delete Style
  • Deleted Style is still in the styles.json in case you wish to retrieve it
• Click Refresh Style to update the Dropdown if you edited the styles.json directly

Advanced Settings

• Process Hires. fix: By default, this Extension only functions during the txt2img phase, so that Hires. fix may "fix" the artifacts introduced during txt2img. Enable this to process Hires. fix phase too.
  • This option does not affect img2img

Noise Settings

let x denote the Tensor ; let y denote the operations

• Straight: All operations are calculated on the same Tensor
  • x += x * y
• Cross: All operations are calculated on the Tensor opposite of the Alt. setting
  • x += x' * y
• Ones: All operations are calculated on a Tensor filled with ones
  • x += 1 * y
• N.Random: All operations are calculated on a Tensor filled with random values from normal distribution
  • x += randn() * y
• U.Random: All operations are calculated on a Tensor filled with random values from uniform distribution
  • x += rand() * y
• Multi-Res: All operations are calculated on a Tensor generated with multi-res noise algorithm
  • x += multires() * y
• Abs: Calculate using the absolute values of the chosen Tensors instead
  • x += abs(F) * y

Scaling Settings

Previously, this Extension offsets the noise by the same amount each step. But due to the denoising process, this may produce undesired outcomes such as blurriness at high Brightness or noises at low Brightness. Thus, I added a scaling option to modify the offset amount.

Essentially, the "magnitude" of the default Tensor gets smaller every step, so offsetting by the same amount will have stronger effects at later steps. This is reversed on the Alt. Tensor however.

• Flat: Default behavior. Same amount each step.
• Cos: Cosine scaling. (High -> Low)
• Sin: Sine scaling. (Low -> High)
• 1 - Cos: (Low -> High)
• 1 - Sin: (High -> Low)

In my experience, 1 - Sin works better for the default Tensor while 1 - Cos works better for the Alt. Tensor

Alt. Disabled

Alt. Enabled

Notice the blurriness and the noises on Flat scaling

Sample Images

• Checkpoint: UHD-23
• Pos. Prompt: (masterpiece, best quality), 1girl, solo, night, street, city, neon_lights
• Neg. Prompt: (low quality, worst quality:1.2), EasyNegative, EasyNegativeV2
• Euler a; 20 steps; 7.5 CFG; Hires. fix; Latent (nearest); 16 H.steps; 0.6 D.Str.; Seed:3814649974
• Straight Abs.

Base
Extension Disabled

Dark
Brightness: -3; Contrast: 1.5

Bright
Brightness: 2.5; Contrast: 0.5; Alt: Enabled

Chill
Brightness: -2.5; Contrast: 1.25
R: -1.5; B: 2.5

Mexican Movie
Brightness: 3; Saturation: 1.5
R: 2; G: 1; B: -2

Notice the significant differences even when using the same seed

Roadmap

• Extension Released
• Add Support for X/Y/Z Plot
• Implement different Noise functions
• Add Randomize functions
• Append Parameters onto Metadata
  • You can enable this in the Infotext section of the Settings tab
• Style Presets
• Implement Color Wheel & Color Picker
• Implement better scaling algorithms
  • Fix the Brightness issues kinda
• Add API Docs
• Add Infotext Support (by. catboxanon)
• ADD HDR Script
• Add Gradient features

X/Y/Z Plot Support
(Outdated Contrast Value)

X/Y/Z Plot w/ Randomize

The value is used as the random seed
You can refer to the console to see the randomized values

API

You can use this Extension via API by adding an entry in the alwayson_scripts of your payload. An example is provided. The args are sent in the following order:

• [Enable, Alt, Brightness, Contrast, Saturation, R, G, B, Process Hires. Fix, Noise Settings, Scaling Settings]

bool, bool, float, float, float, float, float, float, bool, str, str

Known Issues

• Does not work with DDIM, UniPC samplers
• Has little effect when used with certain LoRAs

HDR

BETA

Discussion Thread

• In the Script Dropdown at the bottom, there is now a new option: High Dynamic Range
• This script will generate multiple images ("Brackets") of varying brightness, then merge them into 1 HDR image
• Do provide feedback in the thread!
• Highly Recommended to use a deterministic sampler and high enough steps. Euler (not Euler a) worked the best in my experience.

Settings

• Brackets: The numer of images to generate
• Gaps: The brightness difference between each image
• Automatically Merge: When enabled, this will merge the images using a OpenCV algorithm and save to the HDR folder in the outputs folder; When disabled, this will return all images to the result section, for when you have a more advanced program such as Photoshop to do the merging.
  • All the images are still saved to the outputs folder regardless

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Offset Noise TL;DR

The most common version of Offset Noise you may have heard of is from this blog post, where it was discovered that the noise functions used during training were flawed, causing Stable Diffusion to always generate images with an average of 0.5.

ie. Even if you prompt for dark/night or bright/snow, the overall image still looks "grey"

Technical Explanations

However, this Extension instead tries to offset the latent noise during the inference phase. Therefore, you do not need to use models that were specially trained, as this can work on any model. Though, the results may not be as good as using properly trained models.

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What is Under the Hood

After reading through and messing around with the code, I found out that it is possible to directly modify the Tensors representing the latent noise used by the Stable Diffusion process.

The dimensions of the Tensors is (X, 4, H / 8, W / 8), which can be thought of like this:

X batch of noise images, with 4 channels, each with (W / 8) x (H / 8) values

eg. Generating a single 512x768 image will create a Tensor of size (1, 4, 96, 64)

Then, I tried to play around with the values of each channel and ended up discovering these relationships. Essentially, the 4 channels correspond to the CMYK color format, hence why you can control the brightness as well as the colors.

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Vectorscope?

The Extension is named this way because the color interactions remind me of the Vectorscope found in Premiere Pro's Lumetri Color. Those who are experienced in Color Correction should be rather familiar with this Extension.

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^{Yes. I'm aware that it's just how digital colors work in general.
We've come full circle (*ba dum tss) now that a Color Wheel is actually added.}