Speckle is believed to be a significant degrading factor in ultrasonic images, and likely impairs the detectability of low contrast tumors and clinical scans. One method of reducing speckle, termed frequency diversity processing, uses multiple, narrow-band filters applied to the received RF signal. For this study, several images of targets from a contrast detail phantom were acquired and stored on floppy disks, by digitizing the RF from a mechanically translated transducer. Digital filtering techniques were used to process the images by breaking the RF spectrum into several overlapping bands. Each processed image was computed as both the incoherent and coherent average of the individual narrow-band images. The filters were designed with individually variable weights to broaden and whiten the original transducer spectrum. The resulting processed images showed a degradation of spatial resolution, but a significant increase in grey scale information, and a substantial improvement in the signal-to-noise ratio. The results indicate little difference between coherent and incoherent processing of the images.