Helena Laboratories Corporation

James L Pauley

Henry A Garsee

Charles D Kelley

Gene A Butts

Bruce R Petty

A computer controlled diagnostic densitometer for analyzing optical density patterns of blood samples or the like scans a sample and generates an analog waveform signal representative of the scanned optical density pattern. The analog signal is amplified, digitized, stored in a memory and is later read from memory to reconstruct a visual display of the waveform for analysis. Several types of optical density pattens may be scanned which result in analog signals of different amplitudes and signal-to-background noise ratios. An improved amplification system automatically preadjusts the gain and reference value of the analog signal prior to digitization in order to substantially eliminate background noise in the signal and produce substantially full scale analog signal values. The gain and reference value preadjustments are performed by a pair of corresponding multipliers which multiply the analog signal by memory-stored digital data which is unique to the type of optical density pattern being scanned. The gain and reference voltage may also be manually preadjusted in order to assure sample-to-sample analysis consistency for samples from the same patient.

Densitometer with automatic gain and reference value adjustment of

A method of optically scanning a plurality of optical density patterns, such as blood samples or the like is provided wherein the samples are arranged in rows and each include a plurality of optical density segments extending along a first axis, and wherein the segments generally form columns of like segments along a second axis. The optical densities of a row of segments are first scanned along the first axis, following which the centerlines of each segment in the scanned row is determined along the first axis. Then, the segments of each column are scanned along the corresponding, previously determined centerline. The centerline of each segment is determined by displacing a scanning head relative to the sample along the first axis, measuring the optical density of each segment and correlating the magnitude of the measured optical density with the relative displacement between the head and the samples. The scanning of the segments along the centerlines is performed by displacing the scanning head relative to the samples along the second axis, measuring the optical density of each segment in the column being scanned and correlating the magnitude of the measured optical density with the relative displacement of the head and the samples. Voltages are generated which are proportional to the relative displacement between the head and samples along the first and second axes, and these voltages are converted to digital data and stored in memory for later use in the correlation process. A method is also provided for determining the location of each segment in an optical density pattern and for determining the length of the pattern.

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Salt Lake City, UT, United States of America

James L Pauley