ComfyUI Node: Tonemap (Drago)

Tonemap (Drago):

The CV2TonemapDrago node is designed to apply the Drago tonemapping algorithm to high dynamic range (HDR) images, making them suitable for display on standard dynamic range (SDR) devices. This method is particularly effective for preserving details in both the shadows and highlights of an image, providing a more natural and visually appealing result. The Drago tonemapping algorithm is known for its ability to compress the dynamic range of an image while maintaining local contrast, making it an excellent choice for enhancing the visual quality of HDR images. By adjusting parameters such as gamma, saturation, bias, and mult, you can fine-tune the tonemapping process to achieve the desired visual effect, ensuring that your images look their best on any display.

Tonemap (Drago) Input Parameters:

image

This parameter represents the input image that you want to apply the Drago tonemapping algorithm to. The image should be in HDR format to fully utilize the capabilities of the tonemapping process.

gamma

The gamma parameter controls the gamma correction applied to the image. Gamma correction adjusts the brightness of the image, with higher values resulting in a brighter image and lower values resulting in a darker image. The default value is 1.0, with a minimum of 0.0 and a maximum of 8.0, allowing for fine-tuning in increments of 0.01.

saturation

The saturation parameter adjusts the color saturation of the image. Increasing the saturation value will make the colors in the image more vivid, while decreasing it will make the colors more muted. The default value is 1.0, with a minimum of 0.0 and a maximum of 8.0, allowing for precise control over the color intensity.

bias

The bias parameter influences the overall brightness and contrast of the image. A higher bias value will increase the brightness and contrast, while a lower value will decrease them. The default value is 1.0, with a minimum of 0.0 and a maximum of 1.0, providing a range of adjustment to suit different image characteristics.

mult

The mult parameter is a multiplier that scales the final output image. This allows you to adjust the overall intensity of the tonemapped image, making it brighter or darker as needed. The default value is 1.0, with a minimum of 0.0 and a maximum of 8.0, offering flexibility in the final image output.

Tonemap (Drago) Output Parameters:

IMAGE

The output parameter is the tonemapped image, which has been processed using the Drago algorithm. This image is now suitable for display on standard dynamic range (SDR) devices, with enhanced details in both shadows and highlights, and adjusted brightness and color saturation according to the input parameters.

Tonemap (Drago) Usage Tips:

• Experiment with the gamma parameter to find the right balance of brightness for your image, especially if the original HDR image appears too dark or too bright.
• Use the saturation parameter to enhance or mute the colors in your image, depending on the desired visual effect. Higher saturation can make the image more vibrant, while lower saturation can create a more subdued look.
• Adjust the bias parameter to fine-tune the overall contrast and brightness of the image, ensuring that important details are preserved and the image looks natural.
• The mult parameter can be used to scale the final output image, making it brighter or darker as needed. This is particularly useful if the initial tonemapping result is not at the desired intensity level.

Tonemap (Drago) Common Errors and Solutions:

TypeError: 'NoneType' object is not callable

• Explanation: This error occurs when the tonemap operation is not available in the installed version of OpenCV.
• Solution: Ensure that you have the correct version of OpenCV installed that supports the createTonemapDrago function. You may need to update or reinstall OpenCV.

ValueError: Input image must be in HDR format

• Explanation: This error occurs when the input image is not in the expected HDR format.
• Solution: Verify that the input image is in HDR format. Convert the image to HDR if necessary before applying the tonemapping algorithm.

Invalid parameter value

• Explanation: This error occurs when one or more input parameters are outside their valid range.
• Solution: Check the values of all input parameters to ensure they are within the specified ranges. Adjust any parameters that are out of range and try again.