Performance of a TV image analysis system as a microdensitometer

The performance of a TV image analysis system combined with an automated microscope (the Leitz TAS plus) as a microdensitometer and morphometric device was investigated. There was a strict linear correlation (r greater than .99) between the physically defined optical transmission values and the resulting electronic signals from the plumbicon TV camera for the whole area displayed on the monitor. The shading of the optoelectronic system had a coefficient of variation (CV) of 1.42% for measurements in the center of the displayed area, but a CV of 3.55% for measurements over the whole monitor area. Densitometric measurements remained stable 15 minutes after putting the microscope lamp into operation (T less than 0.075%, remeasuring every two minutes). The geometric distortion, measured as different ferret diameters of ideally round latex particles, ranged from +/- 0.5% to +/- 1.0% deviation over the entire displayed area. These results indicate that densitometric and morphometric measurements with this equipment are sufficiently precise and reproducible when performed in the center of the area displayed on the monitor.