Electronic Camera

Abstract

Disclosed herein is an electronic camera for generating an image having a wide dynamic range by synthesizing two image pickup signals of different exposure amount generated by using an electronic shutter function and means for shutting off light, shading of image pickup signals resulting from difference in charge accumulating time among the pixels of image pickup device due to operation from opened state to closed state of the means for shutting off light being corrected by a shading correction means to form a synthesized image without an occurrence of false color due to shading. Also provided is an electronic camera generating two image pickup signals of different exposure amount by two shots of picture taking each using a flash emission in combination, at least one of an electronic shutter of image pickup device and means for shutting off light, as well as an emission of the flash emission means, being controlled to equalize between the two shots of picture taking ratio of exposure by normal light excluding light from the flash emission means and ratio of emission amount by the light from the flash emission means so that the two image pickup signals can be readily generated as having a predetermined exposure amount ratio in every part of a frame of picture even when a flash emission is used in combination.

1 . An electronic camera comprising:
 a single image pickup device having an electronic shutter function capable of desirably controlling exposure amount by controlling charge accumulating time; and   means for shutting off light from a light receiving surface of the image pickup device; and   image pickup signal of smaller exposure amount generated by using the electronic shutter function of said image pickup device;   image pickup signal of larger exposure amount thereafter generated by controlling charge accumulating time of the image pickup device by the means for shutting off light;   the two image pickup signals synthesized to obtain an image having an increased wide dynamic range;   said electronic camera effecting control of charge accumulating time of the image pickup device by said means for shutting off light through operation from opened state to closed state of the means for shutting off light and further comprising:   shading correction means for correcting shading resulting from difference in charge accumulating time among the pixels of the image pickup device occurring due to the operation toward said closed state of the means for shutting off light.   
   
   
       2 . An electronic camera comprising:
 a single image pickup device having an electronic shutter function capable of desirably controlling exposure amount by controlling charge accumulating time; and   means for shutting off light from a light receiving surface of the image pickup device; and   image pickup signal of smaller exposure amount generated by using the electronic shutter function of said image pickup device;   image pickup signal of larger exposure amount thereafter generated by controlling charge accumulating time of the image pickup device by the means for shutting off light;   the two image pickup signals synthesized to obtain an image having an increased wide dynamic range;   said means for shutting off light comprising a focal-plane shutter, shutter charge of the focal-plane shutter effected immediately after a completion of electronic shutter's operation of said image pickup device in the state where charge accumulating operation of the image pickup device being halted, and charge accumulating operation of the image pickup device started after completion of the shutter charge so as to effect control of a charge accumulating time by a normal focal-plane shutter operation.   
   
   
       3 . An electronic camera comprising:
 a single image pickup device having an electronic shutter function capable of desirably controlling exposure amount by controlling charge accumulating time;   means for shutting off light from a light receiving surface of the image pickup device;   means for generating from said image pickup device two image pickup signals of the same object differing from each other in exposure amount; and   synthesizing means for obtaining an image having an increased wide dynamic range by performing synthesis of the two image pickup signals obtained by the means for generating image pickup signal; and   said means for generating image pickup signal:   generating image pickup signal of larger exposure amount by controlling charge accumulating time of the image pickup device by the means for shutting off light after generating image pickup signal of smaller exposure amount by using the electronic shutter function of the image pickup device if charge accumulating time of the image pickup device for obtaining image pickup signal of larger exposure amount is set as shorter than a time period required for readout of all the pixels of the image pickup device; and   generating image pickup signal of larger exposure amount by using the electronic shutter function of the image pickup device instead of said means for shutting off light if charge accumulating time of the image pickup device for obtaining image pickup signal of larger exposure amount is set as longer than the time period required for readout of all the pixels of the image pickup device.   
   
   
       4 . An electronic camera having a function for performing synthesis of two image pickup signals obtained by
 performing by a single image pickup device two shots of picture taking of different exposure amount of the same object to obtain an image having an increased wide dynamic range, said electronic camera comprising:   a photometric device having a separate entity from the image pickup device; and   means for setting charge accumulating time of the image pickup device at a second shot of picture taking corresponding to a previously set exposure amount ratio of the two shots of picture taking based on an exposure amount measured by said photometric device at a first shot of picture taking.   
   
   
       5 . An electronic camera having a function for performing synthesis of two image pickup signals obtained by performing by a single image pickup device two shots of picture taking of different exposure amount of the same object to obtain an image having an increased wide dynamic range, said electronic camera comprising:
 means for setting diaphragm stop value of lens fixed at said two shots of picture taking.   
   
   
       6 . The electronic camera according to  claim 5 , further comprising exposure setting means, a diaphragm stop value and/or shutter speed obtained by said exposure setting means before taking picture being used at the picture taking for obtaining image pickup signal of larger exposure amount and, at the picture taking for obtaining image pickup signal of smaller exposure amount, the same diaphragm stop value being used and shutter speed being set correspondingly to a previously set exposure amount ratio of the two shots of picture taking. 
   
   
       7 . The electronic camera according to  claim 6 , wherein said exposure setting means sets an exposure value based on photometric output of a photometric device provided separately from the image pickup device. 
   
   
       8 . The electronic camera according to  claim 6 , wherein said exposure setting means sets an exposure value based on image pickup signal of the image pickup device. 
   
   
       9 . An electronic camera having a function for performing synthesis of two image pickup signals obtained by performing by a single image pickup device two shots of picture taking of different exposure amount of the same object to obtain an image having an increased wide dynamic range, said electronic camera comprising:
 means for performing white balance correction for the two image pickup signals of different exposure amount before performing said synthesis by setting the same white balance correction value.   
   
   
       10 . The electronic camera according to  claim 9 , further comprising a white balance setting means, wherein white balance correction value obtained by said white balance setting means before picture taking is used in white balance correction by said white balance correction means. 
   
   
       11 . The electronic camera according to  claim 9 , wherein the correction value to be used in said white balance correction means is set based on image pickup signal before performing said synthesis. 
   
   
       12 . The electronic camera according to  claim 11 , wherein the correction value to be used in said white balance correction means is set based on the image pickup signal of larger exposure amount of the two image pickup signals of different exposure amount before performing said synthesis. 
   
   
       13 . An electronic camera having a function for performing synthesis of two image pickup signals obtained by performing by a single image pickup device two shots of picture taking of different exposure amount of the same object to obtain an image having an increased wide dynamic range, said electronic camera comprising:
 means for correcting white balance with respect to said synthesized image having a wide dynamic range.   
   
   
       14 . The electronic camera according to  claim 13 , further comprising a white balance setting means, wherein white balance correction value obtained by said white balance setting means before picture taking is used in white balance correction by said white balance correction means. 
   
   
       15 . The electronic camera according to  claim 13 , wherein the correction value to be used in said white balance correction means is set based on said synthesized image having a wide dynamic range. 
   
   
       16 . The electronic camera according to  claim 13 , wherein the correction value to be used in said white balance correction means is set based on image pickup signal before performing said synthesis. 
   
   
       17 . The electronic camera according to  claim 16 , wherein the correction value to be used in said white balance correction means is set based on the image pickup signal of larger exposure amount of the two image pickup signals of different exposure amount before performing said synthesis. 
   
   
       18 . An electronic camera having a function for performing synthesis of two image pickup signals obtained by performing by a single image pickup device two shots of picture taking of different exposure amount of the same object to obtain an image having an increased wide dynamic range, said electronic camera comprising:
 gain control means, gain values at said gain control means for said two image pickup signals being respectively set to values differing from each other.   
   
   
       19 . The electronic camera according to  claim 18 , wherein the gain values for said two image pickup signals are set such that the exposure amount ratio of the two image pickup signals corresponds to a previously set exposure amount ratio. 
   
   
       20 . An electronic camera having a function for performing synthesis of two image pickup signals obtained by performing by a single image pickup device two shots of picture taking of different exposure amount of the same object to obtain an image having an increased wide dynamic range, said electronic camera comprising:
 diaphragm control means, said two image pickup signals of different exposure amount being generated by changing diaphragm stop value of lens by the diaphragm control means.   
   
   
       21 . The electronic camera according to  claim 20 , further comprising means for correcting peripheral attenuation of lens, wherein correction with respect to peripheral attenuation occurring due to difference in diaphragm stop value of lens is performed for said two image pickup signals of different exposure amount generated by changing diaphragm stop value of lens by said diaphragm control means. 
   
   
       22 . The electronic camera according to  claim 20 , further comprising flash emission means, wherein the flash emission means effects flash emissions of the same emission amount at said two shots of picture taking of different exposure amount and said two image pickup signals of different exposure amount are generated by changing the diaphragm stop value of lens by said diaphragm stop value control means. 
   
   
       23 . An electronic camera comprising color image synthesizing means for forming a color image having a wide dynamic range by synthesizing a plurality of color image signals of different exposure amount, said electronic camera further comprising:
 weighting means for assigning weights to said plurality of color image signals corresponding to their respective signal level; and   means for adding the plurality of weighted color image signals; and   said weighting means setting the same weighting factor respectively for each color signal in said plurality of color image signals.   
   
   
       24 . The electronic camera according to  claim 21 , further comprising flash emission means, wherein the flash emission means effects flash emissions of the same emission amount at said two shots of picture taking of different exposure amount and said two image pickup signals of different exposure amount are generated by changing the diaphragm stop value of lens by said diaphragm stop value control means.