Image pickup apparatus

Abstract

An image pickup apparatus including: CCD image pickup device; a light blocking plate for shutting out light incident upon the image pickup device; an exposure period controlling section for setting exposure time by controlling the light blocking plate and the image pickup device; a dark signal storing section for storing dark signals obtained from the image pickup device in a state where light is shut out by the light blocking plate; a subtracting section for subtracting the dark signals from main image pickup signals of the image pickup device; a defect detecting section for detecting defects from the subtracted image pickup signals outputted from the subtracting section; and a defect correcting section for performing correction of the detected fault pixels. It is thereby possible to achieve an image pickup apparatus capable of detecting and correcting at high accuracy those fault pixels occurring afterwards because of changes due to the passage of time or those fault pixels transiently occurring under certain modes.

What is claimed is:  
     
         1 . An image pickup apparatus comprising: 
 an image pickup device;    a light blocking means for shutting out light incident upon the image pickup device;    a subtraction means for subtracting a dark signal obtained as an output signal of the image pickup device when shutting out the incident light from a main image pickup signal obtained from the image pickup device at the time of a main image taking;    a correction means for correcting defect signals occurring due to fault pixels of said image pickup device with respect to the subtracted image pickup signal from the subtraction means; and    a control means for controlling said light blocking means consecutively before or after the main image taking so as to obtain a dark signal of a time duration corresponding to the number of occurrence of externally caused fault pixels of said image pickup device.    
     
     
         2 . The image pickup apparatus according to  claim 1 , wherein said control means controls said light blocking means in accordance with an exposure time of the main image taking.  
     
     
         3 . The image pickup apparatus according to  claim 1 , further comprising a temperature detection means for detecting a temperature of said image pickup device, wherein said control means controls said light blocking means in accordance with the temperature detected at said temperature detection means.  
     
     
         4 . An image pickup apparatus comprising: 
 an image pickup device;    a detection means for detecting fault pixels of the image pickup device from image pickup signals of a selected frame by selecting a predetermined frame from image pickup signals consecutively outputted as a plurality of frames from the image pickup device;    a storage means for storing locations of the detected fault pixels;    a correction means for correcting image pickup signals from said image pickup device on the basis of the locations of the fault pixels stored at the storage means; and    a control means for controlling timing at which said fault pixel detection means detects fault pixels.    
     
     
         5 . The image pickup apparatus according to  claim 4 , wherein said fault pixel detection means detects fault pixels at every predetermined number of frames.  
     
     
         6 . The image pickup apparatus according to  claim 4 , wherein said fault pixel detection means detects fault pixels only at the first frame of a number of consecutive frames.  
     
     
         7 . The image pickup apparatus according to  claim 4 , wherein said fault pixel detection means detects fault pixels at predetermined time intervals or during an intermission of photographing after a main photographing.  
     
     
         8 . The image pickup apparatus according to  claim 4  further comprising a motion detection means for detecting a motion in image within a frame, wherein said fault pixel detection means detects fault pixels with respect to a frame or a region within frame of which a motion quantity detected by said motion detection means exceeds a predetermined value.  
     
     
         9 . An image pickup apparatus comprising: 
 an image pickup device;    a storage means for previously storing the locations of fault pixels of the image pickup device;    an edge detection means for detecting edges in image from image pickup signals outputted from said image pickup device;    a fault pixel detection means for detecting fault pixels of the image pickup device from a frame or a region in frame having a value of edges less than a predetermined value on the basis of an output from the edge detection means; and    a defect correction means for obtaining locations of fault pixels by adaptively switching between said fault pixel detection means and the storage means based on an output from said edge detection means so as to correct image pickup signals corresponding to the obtained locations of the fault pixels.    
     
     
         10 . The image pickup apparatus according to  claim 9  further comprising an edge reduction means for forming an image having reduced edges on said image pickup device, wherein said fault pixel detection means detects fault pixels in a state where edges are reduced by said edge reduction means.  
     
     
         11 . An image pickup apparatus comprising: 
 an image pickup device;    a detection means for detecting fault pixels of the image pickup device from image pickup signals outputted from the image pickup device;    a storage means for storing locations of the detected fault pixels; and    a defect correction means for correcting image pickup signals corresponding to the locations of the fault pixels stored at the storage means;    wherein said fault pixel detection means detects fault pixels corresponding to one frame by image pickup signals of a plurality of frames and stores the locations of the fault pixels to said storage means.