Apparatus and method for processing image signal and imaging equipment

Abstract

An image pickup device picks up an image. An image signal in association with the image is filtered in a time axis direction using a digital low-pass filter to generate an image signal having a reduced dynamic resolution power, which is equivalent to an image signal that would be obtained at a longer exposure time. The filtered signal is then subjected to frame skipping processing to generate an output image signal having a preferred frame period. The resultant signal is equivalent to one obtained by a slow shooting.

1 - 14 . (canceled)  
   
   
       15 . An imaging equipment comprising: 
 an image pickup device having an image pickup element for forming an image signal of a dynamic resolution power, said image pickup device having a read period longer than a minimum frame period within which said image pickup element operates;    a digital low-pass filter configured to filter the image signal in a time axis direction thereof to lower the dynamic resolution power for an image based on the image signal;    a processor configured to perform frame skipping on the filtered image signal to form an output image signal having a preferred output frame period; and    a controller configured to control (a) the generation of said image signal by said image pickup device, (b) the filtering characteristic of said digital low-pass filter, (c) the reading by said image pickup element and (d) the frame skipping of said processor; said controller controlling said image pickup device and said processor so that, when the frame period of said output image signal is longer than n (n is an integer) times the minimum frame period but shorter than (n+1) times the minimum frame period, said image pickup device sets the read period of said image pickup device to 1/n times the output frame period and said processor performs frame skipping after every n frames.    
   
   
       16 . The imaging equipment according to  claim 15 , wherein 
 said digital low-pass filter includes a one-frame delay unit supplied with a signal DV e , where DV e =(1−k) DV b +k DV f , and DV b  is the image signal from the image pickup element, DV f  is the output from said one-frame delay unit, k is a coefficient within a range from 0-1 and said signal DV e  is supplied to said processor.    
   
   
       17 . An imaging method comprising the steps of: 
 forming an image signal of a dynamic resolution power from a pickup device having a read period longer than a minimum frame period within which an image pickup element operates;    filtering the image signal in a time axis direction thereof to lower the dynamic resolution power for an image based on the image signal; and    performing frame skipping on the filtered image signal to form an output image signal having a preferred output frame period;    the read period being set to 1/n times the output frame period and frame skipping being performed after every n frames when the frame period of said output image signal is longer than n (n is an integer) times the minimum frame period but shorter than (n+1) times the minimum frame period.    
   
   
       18 . The imaging method according to  claim 17 , wherein 
 the image signal is filtered by a one-frame delay of a signal DVe, where DV e =(1−k)DV b +k DV f , and DV b  is the image signal, DV f  is the result of said one-frame delay, k is a coefficient within a range from 0-1, and said signal DV e  is subjected to said frame skipping.