Image synthesis technology masks the hair with a mask

Hair is one of the hardest things to cover, and if the reader is a portrait photographer and uses Photoshop to synthesize the image, it must be deeply felt about the difficulty. As far as the authors know, many users are interested in this forum on the Internet. The problem most users face is that if you remove the traces of pixels around the hair, these pixels leak out the photo is the secret of using the computer to synthesize. The hair-masking method described below can be used in Photoshop and does not require any additional plug-ins, and this method works in most cases.

The first thing to point out here is that for this method to work, the background must be white or light when taken. If this is not done, it will only increase the difficulty of the task, so planning ahead is essential. All serious synthetic works require a very simple background, such as software Ultimatte AdvantEdge requires a background of blue or green. In this example, however, you will show how to use a white background. The trick here is to copy the existing color channels in the image and modify them to get a new mask channel. This saves a lot of time by using the information contained in an existing color channel to define the edges of the detail rather than using a small pen tool to depict the edges of each strand of hair on the mask. However, pen tools are still useful for depicting broad, smooth contours of a model's neck, shoulders, and arms.

1. The next steps describe how the author shoots the model and then adds a different background.

I usually use a white background when I shoot, because it's convenient for covering small hairs. In this example, the background contains some details, but you can still use the photo itself to create the mask.

2. First look at the color channel and copy the channel with the highest contrast.

In this example, the contrast between the background and the hair in the green channel is the highest, so drag it over the channel palette onto the Create new channel button to copy it.

3, the next steps are for the "Green copy" channel (when the reader completes these actions, make sure that the channel is selected).

You need to increase the contrast of the alpha channel to make the hair darker. To do this, select the menu "image" > "Apply Image". As the reader sees it, the target channel is "green copy" and the blending mode is superimposed, so this is equivalent to applying overlay mode to the alpha channel. In the Apply Image dialog box, you can select a variety of channel blending modes, but most of the time the author uses a positive overlay mode and tries to mix two color channels. The goal at this stage is to improve the contrast between the hair and the background to use the pixel information already in the photo.

4, the 3rd step makes the Mask channel appearance completely different, now needs to improve the contrast.

To do this, select the Brush tool, set the pattern to overlay, and toggle the foreground color between black and white. In overlay mode, when you use black paint, the drawing will only be used for darker pixels, while white paint is used only for lighter pixels. Overlay mode is a useful painting mode, allowing the user to use a large brush to gradually increase the color intensity around the black hair bundle without affecting the tint area. Continue painting, and be careful not to make the color intensity of the external hair bundle too large. I also want to point out that I like to use a pressure-sensitive pen and drawing board for painting, and in the "other dynamic" of the tone plate, the opacity control is set to "pen pressure".

5, next consider covering the other parts of the model.

The model's clothes are almost the same color as the background color, so the best way to isolate the rest of the model is to draw a pen path along the sleeves and neck of the garment.

6. Use the Pen tool to draw a path covering the upper part of the model, which covers the model's chin and earrings.

Then, in the Path palette, drag the path 1 to the selection by dragging it onto the "load the path as a selection" button. Fill the selection with black and use the brush tool to paint in normal mode on the other part of the face.

7, create a good mask, you need to add a new background.

Open a picture of a textured wall and drag the background image to the Model image window using the Move tool. This will add the background as a new layer. In the Layer palette, set the blending mode to "multiply", which will project the new layer onto the background layer. When layer 1 is active, select menu Edit > Free transform, and then drag the handle to scale the layer.

8. In the Channel palette, drag the green copy channel of the channel to the "Load channel as a selection" button, and then click the Add Layer Mask button in the Layer palette to convert the active selection to a layer mask.

9, the layer mask effect is very good, but still need to do some fine-tuning.

First, in the history palette, make sure that the check box "Allow Non-linear history" is selected in the History Options dialog box. Select the layer Mask, select the menu "Filter" > "Other" > "Max", then select "Filters" > "blur" > "Gaussian Blur", and then use the settings shown in the figure to make "levels" adjustments. These actions are designed to narrow the mask that covers the hair.

10. Now, the reason for setting the history palette to allow Non-linear history will appear.

In the previous step, use a "level" adjustment to improve the mask, but doing so will cause the edges of the mask around the shoulders and neck to be smooth. In the History palette, click the history state "Gaussian blur" (Note that the history status level is not dimmed), and then apply another level adjustment: Modify the layer mask, but make sure the edges around the body remain smooth. In the History palette, click in the empty box to the left of the first level, and set it to the source history state. Then select the history Brush in the tool palette and paint around the edge of the hair to restore the best hair mask status.

Here's a summary. In step 9th, modify the mask to fit the contour of the hair; step 10th sets the history state to the source state, and then reverts to the history state "Gaussian Blur", which is used as the starting point for another "level" adjustment, which is best for the other contours of the model. Then use the history brush to paint the contour of the hair to restore it to the first use of the levels adjusted state.

Category:

• PS Image Processing
• PS Mask Tutorial