The goal of this study was to develop a calibrated on-line technique to ext
ract as much diagnostically-relevant information as possible from conventio
nal video-format echograms. The final aim is to improve the diagnostic pote
ntials of medical ultrasound. Video-output images were acquired by a frame
grabber board incorporated in a multiprocessor workstation. Calibration ima
ges were obtained from a stable tissue-mimicking phantom with known acousti
c characteristics. Using these images as reference, depth dependence of the
gray level could fairly be corrected for the transducer performance charac
teristics: for the observer-dependent equipment settings and for attenuatio
n in the examined tissues. Second-order statistical parameters still displa
yed some nonconsistent depth dependencies. The results obtained with two ec
hoscanners for the same phantom were different; hence, an a posteriori norm
alization of clinical data with the phantom data is indicated. Prior to pro
cessing of clinical echograms, the anatomical reflections and echoless void
s were removed automatically. The final step in the preprocessing concerned
the compensation of the overall attenuation in the tissue. A 'sliding wind
ow' processing was then applied to a region of interest (ROI) in the 'back-
scan converted' images. A number of first and second order statistical text
ure parameters and acoustical parameters were estimated in each window and
assigned to the central pixel. This procedure results in a set of new 'para
metric' images of the ROI, which can be: inserted in the original echogram
(gray value, color) or presented as a color overlay. A clinical example is
presented for illustrating the potentials of the developed technique. Depen
ding on the choice of the parameters, four Full resolution calibrated param
etric images can be calculated and simultaneously displayed within 5 to 20
seconds. In conclusion, an on-line technique has been developed to estimate
acoustic and texture parameters with a reduced equipment dependence and to
display acoustical and textural information that is present in conventiona
l echograms.