Nov
11
2010

Extract Any Object From An Image Using Channels

For a Digital Manipulation to look real and believable it is very important that the subject being extracted from the stock is flawless. In this Tutorial I will cover a handy trick to achieve the flawless extraction using quick selection tool and channels. Here I would be using a stock photo of a Desert Dancer provided by Marcus Ranum.

Extract Any Object From An Image Using Channels

1. To extract the dancer from its background we need to make sure that the contrast between the background and the dancer is high.  Move to the channels palette shown below to choose from different channels.

Extract Any Object From An Image Using Channels

2. Next goto the channels and check each channel separately, the shortcuts are Red – Ctrl+1, Blue - Ctrl+2, Green – Ctrl+3 , RGB – Ctrl+~.The objective here is to find a channels that gives the maximum amount of variation of the Dancer as compared to its background. Hence in this case we will choose the Blue Channel. . Make sure that only one channel is active at a time.

Extract Any Object From An Image Using Channels

3. Select the quick selection tool and the brush size as 60px and  start selecting the background. This will make a rough Raw selection around the Dancer.

Extract Any Object From An Image Using Channels

4. To fine tune the selection alter the brush size and make finer selections. I have marked the areas that need finer tuning with Red Circles. The brush sizes that i have used ranged frm 1px to 3 px depending on the thickness of the object to be selected.

Extract Any Object From An Image Using Channels

5. Once selected make sure that all channels are visible and the currently selected channel is RGB. Then revert to the layer view with the Dancer Layer selected and your selection from the channels view still intact. Hit delete and voila! You will now be left with a perfectly selected dancer with somewhat jagged edges.

Extract Any Object From An Image Using Channels

6. To give a smooth finish goto select>modify>feather. Put 1 px and hit OK. Now press ctrl+shift+i to invert the selection and hit delete. So now you will be left with a curvier dancer with smoother finish. Here is what my dancer looked like.

Extract Any Object From An Image Using Channels

Additional Tip :

You can also fine tune your selection in the quick  selection mode by clicking on refine edge.  And to remove any unwanted parts use the eraser tool.

I hope you enjoyed this tutorial and learnt how to extract objects quickly and precisely.

1 Comment + Add Comment

  • Useful guide! Thank you very much! Even a rookie like myself succeeded in the task, following these easy steps!

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