The Sharpen Edges filter
You can use the Sharpen Edges filter to adjust the sharpness of your images. It works by determining the edges of elements in the image based on the degree to which one color in an image contrasts with another.
To sharpen the edges in an image
Select an image file.
On the Window menu, click Image Editor.
Click the Sharpen Edges filter.
In the Sharpen Edges dialog box, drag the Sharpening slider to define the number of pixels (from 1 to 10) to retouch the edge.
Use the Edge Detection slider to adjust how strong the contrast of edges must be before a pixel is within the range to be sharpened.
Be careful not to over-sharpen the image. If you do, you will reveal imperfections by making JPEG artifacts more visible.