To evaluate image screening performance based on
screening criterion J, we conducted two object detection
tasks: detecting the eye and mouth area in a face image and
the text area in a document image. The a priori
probabilities fF and PG are different in these tasks. The
face image database 121 and the UW English document
image database [ 12 1 were used for the experiments. The
right-way-up frontal face image consists of 128x 1 20
pixels. Eight face images were used to take a set of
subimages { W} for learning and another eight face images
were used to take subimages for testing. In the document
image database, 36 grayscale images were used for learning
samples, and the other 36 were used for test samples.
These images contain text areas, tables, figures, line
drawings, etc. Because the original size of each image was
large, all images were reduced in size by twelve percent so
that a masked subimage consisting of 30x30 pixels could
cover a few lines in the text area.