The DSP explanations are great, with less math. Although if are trained in signals and systems already and just need to take the jump to DSP, Understanding DSP by Lyons is supposed to be the best (haven't read it myself).
These are the books which helps u a lot as a beginner...
1>Andre Marion, “An introduction to image processing”, Chapman
and Hall, 1991.
2>Gregory A. Baxes, “Digital Image Processing, principles and
applications”, John Wiley & Sons, 1994.(very good book..but i donot have )
3>Edward R. Dougherty and Charles R. Giardina, “Image processing continuous
to discrete”, Prentice Hall, 1987.