Exposure & Contrast¶
Equalize Adapthist¶
Applies CLAHE (Contrast Limited Adaptive Histogram Equalization) to enhance local contrast.
Details
- clip_limit — controls contrast amplification; lower values produce subtler enhancement (default: 0.01).
| Direction | Port | Type |
|---|---|---|
| Input | image |
image |
| Output | image |
image |
Properties: Clip Limit
Image Math¶
Performs pixel-wise arithmetic and logical operations on one or two images or masks.
Details
Two-input operations (connect both A and B):
- A + B — add and clip to [0, 1]
- A - B — subtract and clip to [0, 1]
- A x B (image) — element-wise multiply
- A x B (apply mask) — mask A by B:
A * (B > 0) - A AND B — mask intersection
- A OR B — mask union
- Max(A, B) — element-wise maximum
- Min(A, B) — element-wise minimum
- Blend — weighted blend:
A*v + B*(1-v)
Single-input operations (only A is required):
- Invert A —
1 - A - Normalize A — stretch to [0, 1]
- Gamma A^v —
A^vwhere v is the scalar value - Threshold A > v — binary threshold
Custom expression mode:
- Custom Expression — type any math using A, B, v as variables.
Available functions: abs, sqrt, log, log2, log10, exp, sin, cos, clip, max, min, mean, std.
Example:
A ** 2 + B,clip(A * 2, 0, 1),sqrt(A)
| Direction | Port | Type |
|---|---|---|
| Input | A (image/mask) |
image |
| Input | B (mask) |
mask |
| Output | image |
image |
| Output | mask |
mask |
Properties: Operation
Brightness / Contrast¶
Adjusts brightness and contrast interactively using a histogram with draggable Min/Max lines.
Details
Drag the red Min line and cyan Max line on the histogram to set the display window. The output image is always 8-bit with a linear stretch: output = clip((pixel - Min) / (Max - Min) * 255, 0, 255).
Works with 8-bit and 16-bit input images. For 16-bit input the histogram spans 0-65535 and the handles can be placed anywhere in that range.
Convenience controls:
- Brightness (-100 to +100) — shifts the window centre up or down
- Contrast (-100 to +100) — narrows or widens the window symmetrically
| Direction | Port | Type |
|---|---|---|
| Input | image |
image |
| Output | image |
image |
Gamma Contrast¶
Applies gamma correction to adjust image tonality non-linearly.
Details
Transforms each pixel via O = I^gamma * gain.
-
gamma — exponent controlling the curve shape (default: 1.0). Values below 1 brighten; values above 1 darken.
-
gain — multiplicative scaling factor applied after gamma (default: 1.0).
| Direction | Port | Type |
|---|---|---|
| Input | image |
image |
| Output | image |
image |
Properties: Gamma, Gain
Multi-Channel B&C¶
Per-channel brightness & contrast with live composite preview.
Details
Connect 1–4 grayscale channels (or a single multi-channel image) and adjust each channel's display window independently. Each channel has its own histogram with draggable min/max lines, brightness/contrast sliders, and a color button. The composite output blends all channels additively.
Works as a single-channel B&C node when only one input is connected.
| Direction | Port | Type |
|---|---|---|
| Input | ch1 |
image |
| Input | ch2 |
image |
| Input | ch3 |
image |
| Input | ch4 |
image |
| Output | ch1 |
image |
| Output | ch2 |
image |
| Output | ch3 |
image |
| Output | ch4 |
image |
| Output | composite |
image |