IMAGE DETECTOR

In the image detector according to the present invention, a signal processing block generates a video signal by processing a pickup image signal corresponding to an image of an object which is picked up by an image pickup block and a motion detection block detects variations per unit time of luminance or a color of a portion or a whole of an image formed on the basis of the video signal as character variables of the image. A character analyzing block divides the video signal generated by the signal processing block into signals at durations each having the same character variable of the image detected by a motion detection block, and adds, to each of the divided video signals, an importance degree determined according to the character variables of the image and a duration of the signal, thereby making it possible to save memory capacities, accelerate retrieval of pickup images and enhance utilization efficiencies of transmission systems for lessening loads.