Adding or removing noise

The term "noise" in photography refers to unwanted single pixels or groups of pixels that do not belong in the photo. The noise can be caused various factors. Usually, the problems are either introduced electronically by the camera itself or caused by file formats such as JPEG. Noise appears as colored specks within the photo. You can display the noise best by zooming in. For example, you might see specks of red, pink, green, and yellow in a photo of a clear blue sky.

Corel PaintShop Pro gives you many ways to remove various types of noise, and it even lets you add noise to an otherwise "clean" photo. You can make the following corrections by applying them to a selection or an entire image:

In addition, you can use the One Step Noise Removal and the Digital Noise Removal commands. For more information, see To remove digital noise quickly and To use advanced options for removing digital noise.

To add noise

Edit workspace 

1	Choose Adjust Add/Remove Noise Add Noise.

You can use black-and-white noise pixels by marking the Monochrome check box. To use colored pixels, unmark the check box.

To remove scratches automatically

Edit workspace 

1	Choose Adjust Add/Remove Noise Automatic Small Scratch Removal.

To limit the correction to a specific area, make a selection. The command works better when applied to a selection than when applied to an entire image.

To sharpen video capture images

Edit workspace 

1	Choose Adjust Add/Remove Noise Deinterlace.

You should apply the Deinterlace command before you resize the image. Resizing adds or removes pixels from the image, which makes it more difficult to identify scan lines. If your image has already been resized, you must return it to the original size as closely as possible so that each scan line is 1 pixel high. Using the zoom control in the dialog box, you can zoom until you can see how many pixels make up one scan line, and then you can resize the image so that each scan line is 1 pixel high. For example, if the enlarged image has scan lines that are 2 pixels high, you would resize it by 50 percent. Note that resizing the image causes it to lose clarity.

To remove artifacts from JPEG images

Edit workspace 

1	Choose Adjust Add/Remove Noise JPEG Artifact Removal.

You can apply the JPEG Artifact Removal command to a file in any format. For example, if you have saved a JPEG file to the Corel PaintShop Pro (.pspimage) format, you can still apply the command.

Because JPEG compression discards image information, the ability to restore JPEG images is limited.

To remove moire patterns

Edit workspace 

1	Choose Adjust Add/Remove Noise Moire Pattern Removal.

After you have removed the moire pattern, you may be able to use the Sharpness commands in the Adjust menu to restore detail and remove blurriness without reintroducing the pattern. The Sharpness commands work best when you choose a Fine details setting in the Moire Pattern Removal dialog box that is slightly higher than needed to remove the pattern.

To remove single-pixel specks

Edit workspace 

2	Choose Adjust Add/Remove Noise Despeckle.

To remove noise while preserving edges

Edit workspace 

2	Choose Adjust Add/Remove Noise Edge Preserving Smooth.

Although you can apply the Edge Preserving Smooth command to the entire image, the command works best when you select the problem area.

To remove distinct areas of noise

Edit workspace 

2	Choose Adjust Add/Remove Noise Median Filter.

Although you can apply the Median Filter command to the entire image, the command works best when you select the problem area.

To remove multipixel specks

Edit workspace 

2	Choose Adjust Add/Remove Noise Salt and Pepper Filter.

Although you can apply the Pepper Filter command to the entire image, the command works best when you select the problem area.

You can remove all specks that are smaller than the Speck size value by marking the Include all lower speck sizes check box.

You can intensify the strength of the correction by marking the Aggressive action check box.

To remove noise while preserving textures

Edit workspace 

2	Choose Adjust Add/ Remove Noise Texture Preserving Smooth.

Although you can apply the Texture Preserving Smooth command to the entire image, the command works best when you select the problem area.

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