ComfyUI Node: Luminance Stack Processor (3 Stops)

Luminance Stack Processor (3 Stops):

The LuminanceStackProcessor3Stops node is designed to enhance the dynamic range of images by combining multiple exposures into a single high dynamic range (HDR) image. This process, known as exposure bracketing, involves capturing images at different exposure levels and merging them to create a final image that retains details in both the shadows and highlights. The node is particularly useful for scenes with a wide range of brightness levels, allowing you to produce images with greater detail and depth. By leveraging advanced algorithms such as "detail injection," the node ensures that the resulting HDR image is both visually appealing and true to the original scene. This node is an essential tool for AI artists looking to create images with enhanced luminance and contrast, providing a more realistic and immersive visual experience.

Luminance Stack Processor (3 Stops) Input Parameters:

ev_plus_2

This parameter represents the image captured at +2 exposure value (EV), which is typically brighter than the base exposure. It helps in capturing details in the shadow areas of the scene. The input should be an image file or data that corresponds to this exposure level.

ev_0

The ev_0 parameter is the base exposure image, which is captured at the normal exposure level. This image serves as the reference point for the HDR process and is crucial for maintaining the overall balance of the final image. It should be an image file or data that represents the standard exposure.

ev_minus_2

This parameter is the image captured at -2 EV, which is generally darker than the base exposure. It is essential for capturing details in the highlight areas of the scene. The input should be an image file or data that corresponds to this exposure level.

exposure_step

The exposure_step parameter defines the interval between the different exposure levels. It is typically set to 2.0, which means each exposure is two stops apart. This parameter helps in determining the range of exposures to be combined.

exposure_adjust

This parameter allows for fine-tuning the overall exposure of the final HDR image. It is set to 0.0 by default, meaning no additional adjustment is applied. Adjusting this value can help in achieving the desired brightness level in the final image.

hdr_algorithm

The hdr_algorithm parameter specifies the algorithm used for merging the exposures. The default is "detail_injection," which focuses on preserving fine details in the HDR image. This choice affects the quality and appearance of the final image.

auto_calibrate

This boolean parameter, when set to True, enables automatic calibration of the exposure levels to ensure optimal results. It is useful for correcting any discrepancies in the exposure values and achieving a balanced HDR image.

debevec_exposure_comp

The debevec_exposure_comp parameter is used for exposure compensation during the HDR process. It is set to -8.0 by default and helps in adjusting the exposure levels to prevent overexposure or underexposure in the final image.

debevec_anti_banding

This boolean parameter, when set to True, activates anti-banding measures to reduce the appearance of banding artifacts in the HDR image. It is particularly useful in scenes with smooth gradients or uniform areas.

Luminance Stack Processor (3 Stops) Output Parameters:

hdr_image

The hdr_image is the final output of the node, representing the high dynamic range image created by merging the input exposures. This image retains details in both the shadows and highlights, providing a more realistic and visually appealing representation of the scene. The output is typically an image file or data that can be further processed or used in various applications.

Luminance Stack Processor (3 Stops) Usage Tips:

• Ensure that the input images are aligned and free from motion blur to achieve the best results. Using a tripod during capture can help maintain alignment.
• Experiment with the exposure_adjust parameter to fine-tune the brightness of the final HDR image, especially if the initial result is too bright or too dark.
• Utilize the auto_calibrate feature to automatically correct exposure discrepancies, which can be particularly helpful when working with images captured under varying lighting conditions.

Luminance Stack Processor (3 Stops) Common Errors and Solutions:

3-Stop HDR processing failed

• Explanation: This error occurs when the HDR processing encounters an issue, such as misaligned images or incompatible input data.
• Solution: Check that the input images are correctly aligned and in the appropriate format. Ensure that the exposure values are consistent and that the images are free from significant motion blur. If the problem persists, try adjusting the exposure_step or hdr_algorithm parameters to see if different settings resolve the issue.