Step 1: Open your image. Put a selection around the part of the image that you would like to put the pop dots effect behind.(Inverse if you need to.)
Step 2: Press apple+J twice. Put a selection around layer 2.
Step 3: Go under the Select menu, under modify, and choose Expand. Enter 10 pixels and click OK.
Step 4: Press "D" to switch your swatches to the default colors. Options + Delete.
Step 5: Press the letter "Q" to enter Quick Mask mode. Go under the Filter menu, under Pixelate, and choose Color Halftone. CLick Ok.
Step 6: Keep running your filter until you are satisfied with the results. Tap the letter "Q" to leave quick mask mode.
Step 7: Option+Delete. Deselect your image.
