Tutorial: AKVIS Noise Buster

How It Works

AKVIS Noise Buster reduces both luminance and color noise on images without spoiling other aspects of the photo. The software can work independently as a standalone program and as a plug-in to a photo editor.

Compare the fragment below before and after filtration with AKVIS Noise Buster.


Before AKVIS Noise Buster	After AKVIS Noise Buster

Follow the instructions below to reduce noise on a picture using AKVIS Noise Buster.

Step 1. Run the standalone edition of AKVIS Noise Buster or open your photo editor (if you work with the plugin version of AKVIS Noise Buster).
Step 2. Open an image.
- If you work with the standalone edition:

The dialog box Select File to Open appears if you double-click on the empty workspace of the program or if you click on the button on the Control Panel. You can also drag the required image into the workspace of the program. The program supports images in the JPEG, TIFF, BMP, PNG, and RAW formats (CRW, NEF, ORF, PEF etc - see the full list here). You can also drag the required image into the workspace of the program.

- If you work with the plugin:

Open an image in your photo editor by calling the command File -> Open or using the key combination Ctrl+O (or +O on Macintosh).
Step 3. In plug-in version only: call the AKVIS Noise Buster plug-in. For this purpose call the command Filter –> AKVIS –> Noise Buster in Adobe Photoshop; Effects –> Plugins -> AKVIS –> Noise Buster in Corel Paint Shop Pro; Effects –> AKVIS –> Noise Buster in Corel Photo-Paint.

Step 4. Once the program is open, it will begin processing the image using the default settings (the Automatic Filtering preset).
Auto Filtering automatically chooses the best settings for particular kinds of noise by adjusting 4 noise suppression parameters.
The result of the filtration will be shown in the Preview Window of the Before tab.
The Preview Window is represented by a dotted frame. You can drag the frame or draw it anew on any part of the image, thus analysing different parts of the photo.

You can compare the filtered result with the original image by left clicking in the preview area.
It's possible to change the size of the quick preview area in the program's Preferences .
To process the entire image, press the button . Filtering of the entire image also starts when the After tab is pressed.
After processing it is possible to switch between Before/After tabs by pressing the left mouse button anywhere in the image window.

Step 5. If the result of automatic filtration is not wholly satisfying you can adjust the settings to achieve the best result.

The task of noise reduction is to find the golden mean between suppressing noise and keeping detail. Besides, it is important to take into account the psychological characteristics of visual perception: when comparing the original and the filtered photo pay your attenti not only to details but to the overall impression as well. A certain amount of noise does not necessarily spoil a picture, while some smoothness of a photo may add to the visual effect (especially in portrait retouching where it is not desirable to see the skin structure in detail).

Noise on any color picture can be divided into: luminance noise and color noise.

Luminance noise is perceived as dark dots or small blots, color noise represents color spots on areas having a different color. Another name for color noise is chroma noise.

The Histogram below the Settings is a graphical depiction of the noise level and noise components of the original picture. The gray area shows the luminance noise; the red area shows the color noise. The more the histogram is shifted to the right, the higher the noise level is. And vice versa, if the histogram is shifted to the left, the image has a low noise level. The height of the histogram displays the number of pixels having this noise level. When adjusting the parameters, pay attention to the right part of the histogram, as it shows the amount of highly noised pixels. The amount of pixels in the left part shows low noised pixels that are a part of the picture, its natural background.

To reduce noise of each type (Luminance Noise / Color Noise) there are two parameters to manipulate: Noise Level and Smooth Level.

Noise Level. The parameter defines which elements of the image are to be considered noise (luminance or color) and which are to be considered important details. At high value of the parameter small details can be defined as noise and, therefore, be smoothed.
Smooth Level. The parameter sets the extent to which the elements defined as noise should be smoothed. The higher the parameter, the smoother the filtration result. However, at high values of the parameter, an image can lose detail and look flat. High values of the parameter Smooth Level for color noise can produce an alteration of colors and loss of small color details.

Note: On a grayscale photo there is no color component and therefore no color noise. To suppress noise on a grayscale photo it is enough to regulate the parameters of the Luminance Noise.

Attention! The Histogram is only a graphic representation of the picture's noise level. It does not change as you change the settings. The histogram helps you estimate the noise level and decide what parameters should be adjusted.

Fade. This parameter sets the mixing ratio of the filtered image and the original. The parameter values vary between 0 and 100%. At 100% all elements of the photo defined as noise are smoothed in accordance with the value of the parameter Smooth Level. As you move the slider to the left (i.e. reduce the value of the parameter), the original image noise mixes into the filtered image; at 0% there is no filtration at all. In most cases a certain amount of original noise adds to the natural look of an image and allows restoring small details.

In addition to these main (noise reduction) parameters there is the Improve Detail group of the parameters:

Microdetail. The parameter restores small details on the image. The default value usually offers a satisfactory result, but it is possible to increase the value of the parameter to improve sharpness.
Edge Intensity. The parameter makes the edges and borders more visible without revealing noise. The higher the value, the stronger the effect - the edges become clear and well-defined.
Sharpness. The parameter changes the contrast of adjacent pixels. Use this parameter carefully, it can return digital noise to the image.

Step 6. To process the entire image, press the button .

Step 7. You can also use the post-processing tools on the After tab: the Smart Blur tool and the History Brush tool .
Attention! If you change the parameters and run the image processing again, the changes made with these tools will be lost.
- The Smart Blur tool smoothes out grain and noise while preserving outlines and fine details. It is available only under Home Deluxe and Business licenses.
  
  Fragment of the Original Image After Processing with the Smart Blur tool
- The History Brush tool restores areas to their original state. This tool is available for everyone.
  
  Fragment of the Original Image After Processing with the History Brush

Step 8. It is possible to save the settings you like as a preset and use them in the future. The presets are also helpful when working in the batch processing mode.
To save a preset, enter a name for the preset into the Presets field and press the button Save. If you change the values of the parameters, you can always come back to the default settings of the preset by pressing the button Reset.
To delete a preset, select it from the list and press Delete.
To process an image with the settings of a certain preset, you should select it from the drop-down menu and press the button .
Step 9. In plug-in version only: to apply the filtration result to the image and close the plug-in's window, press the button .
Step 10. Save the processed image.
- If you work with the plugin:

Call the Save As dialog box using the command File -> Save As, enter a name for the file, choose the format and indicate the target folder.

- If you work with the standalone edition:

Click on the button to open the Save as dialog box. Enter a name for the file, choose the format (TIFF, BMP, JPEG or PNG) and indicate the target folder.
Step 11. The standalone edition of AKVIS Noise Buster allows printing the image. For this purpose press the button , adjust print settings and press the button Print.
Step 12. Close the program AKVIS Noise Buster.