You could use the Pen Tool to make a selection around each letter in turn, once you have the path, go to select, modify and expand by one pixel, then hit Shift + Backspace to fill the selection with black.
Not in PS unless you're ready for a long job.
But if you have Illustrator (or CorelDraw) you can import that picture and use the trace feature.
Then use the nodes to 'rectify' the text.
I did it quickly in CorelDraw and exported the picture as a PNG to get this:
I'm not doing my best thinking in the morning Ged...
I tried with select/modify and contract it 2 px, making a new selection and paint it with the brush several times (color fill with alt+del doesn't work well) and then again select/expand but the result isn't any good so I proposed AI or CD...
Knowing how you created this would have helped so with no other option I'm going to guess it was hand drawn with a brush of some description.
If that is the case then check the properties of the brush, especially the 'Spacing' setting.....for some annoying reason Adobe decided it was a good idea to have a certain amount of 'spacing' on the default brushes, and furthermore another good idea that you cannot completely remove it.....genius. (And no, unchecking it just makes things worse!...even more genius.)
Despite that, setting this property to its lowest does smooth out the brush considerably...
- Create Layer underneath original of the same background color
- Create selection of text and turn to Layer Mask
- Change Text Layer to solid black (mask preserves letter)
- Use Select and Mask on the Layer mask with using sliders of smoothness a tad, feather a tad and turn up the contrast