1. A picture processing apparatus, comprising: infrared picture producing means for producing an infrared picture designating a heat distribution of a measured area in which one or more persons surrounded by environments stay, the infrared picture being composed of a plurality of pixels having temperatures of the measured area as pixel values; infrared picture storing means for storing the infrared picture produced by the infrared picture producing means; partitioned block representative temperature calculating means for partitioning the infrared picture stored in the infrared picture storing means into a plurality of picture blocks and calculating average temperatures of the picture blocks as representative temperatures of the picture blocks; picking-out temperature determining means for determining a temperature range for each of the picture blocks according to each of the representative temperatures calculated by the partitioned block representative temperature calculating means; human-area picking out means for picking out one or more human-areas from each of the picture blocks partitioned by the partitioned block representative temperature calculating means on condition that temperatures of pixels in each of the picture blocks are within the temperature range determined by the picking-out temperature determining means, and the persons being placed in the human-areas; representative point calculating means for calculating a representative point of each of the human-areas picked out by the human-area picking out means; personal characteristic data extracting means for extracting pieces of personal characteristic data designating characters of the persons from the infrared picture stored in the infrared picture storing means according to the human-areas picked out by the human-area picking out means, the representative points calculated by the representative point calculating means and the environments; environmental characteristic data extracting means for extracting pieces of environmental characteristic data designating characters of the environments from the infrared picture stored in the infrared picture storing means; and picture information detecting means for detecting pieces of personal information pertaining to the persons or pieces of environmental information pertaining to the environments according to the personal characteristic data extracted by the personal characteristic data extracting means and the environmental characteristic data extracted by the environmental characteristic data extracting means.