Image input apparatus having addition and subtraction processing

Abstract

Image data having a high S/N ratio is obtained even when the exposure time is relatively long. To achieve the above object, there is provided an image input apparatus in which an accumulation mode is set with the shutter open, thereby acquiring image data A 1. The shutter is then closed, and the accumulation mode is set to acquire subtraction data between the image data and black image data A 2. This processing is repeated to acquire image data A 1 and subtraction data A 2, and these subtraction data are added. These operations A 1, A 2, and A 3 are repeated a predetermined number of times to update addition data, and image processing is performed on the basis of the updated addition data.

1 - 22 . (canceled)  
     
     
         23 . An image input apparatus comprising: 
 an image pickup region including a plurality of pixels each for converting an optical image from an object into electrical image information and accumulating the electrical image information; and    a processing circuit adapted to process the electrical image information from said image pickup region,    wherein said processing circuit generates image data by performing a subtraction operation and an addition operation on the basis of a plurality of first image information read out in a time-series manner from the same pixel during one exposure operation, and a plurality of second image information sequentially read out from the same pixel in a shielded state.    
     
     
         24 . An image input apparatus comprising: 
 image pickup means for converting an optical image from an object into electrical image information and accumulating the electrical image information;    shielding means for shielding said image pickup means from incidence of the optical image; and    processing means for processing the image information from said image pickup means,    wherein said processing means comprises: 
 first image information acquiring means for acquiring first image information accumulated in said image pickup means with said shielding means open,  
 second image information acquiring means for acquiring second image information accumulated in said image pickup means with said shielding means closed,  
 subtraction processing means for executing a subtraction process between the first image information acquired from said first image information acquiring means and the second image information acquired from said second image information acquiring means,  
 repetitive executing means for repetitively executing the operations by said first image information acquiring means, said second image information acquiring means, and said subtraction processing means a predetermined number of times, and  
 addition means for adding the results of the repetitively executed subtraction process by said subtraction processing means.  
   
     
     
         25 . An image data processing method comprising: 
 an image pickup step of converting an optical image from an object into electrical image information and accumulating the electrical image information in image pickup means;    a shielding step of shielding said image pickup means from incidence of the optical image by using shielding means; and    a processing step of processing the image information from said image pickup means,    wherein the processing step comprises: 
 a first image information acquisition step of acquiring first image information accumulated in said image pickup means with said shielding means open,  
 a second image information acquisition step of acquiring second image information accumulated in said image pickup means with said shielding means closed,  
 a subtraction step of executing a subtraction process between the first image information and the second image information,  
 a repetition step of repetitively executing the first image information acquisition process, the second image information acquisition process, and the subtraction process a predetermined number of times, and  
 an addition step of adding the results of the repetitively executed subtraction process.