METHOD AND DEVICE FOR AGGREGATION DECISION

PURPOSE:To decide aggregation without being affected by variance in the contrast of an aggregation image by obtaining a variation coefficient from the distribution state of picture elements whose brightness levels are not 0 among picture elements in the contour of a differential image. CONSTITUTION:The aggregation image on a microplate 7 is picked up by a TV camera 12 and stored in an image memory 13, and the differential image is obtained by a differential processor 14. Then the contour and area of the image are obtained by an image processor 15. Then a standard deviation calculation device 16 obtains the standard deviation S of picture elements whose brightness levels are >=0 to obtain the variation coefficient CV. Those coefficient CV and area are supplied to a plotter 18 and plotted. This operation is carried out for many samples. On the other hand, plural visual deciding persons make decisions and their results are plotted. Then a boundary determining device 20 determines a straight line which divides a positive and a negative area and stores it in a memory 21. Then the straight line on the plotter 18 which is obtained from an undecided aggregation image is compared with a criterion stored in a memory 21 by a comparing device to make a decision.