Controlling method and apparatus for an electronic camera

Claim 3

The method of claim 1 , wherein said setting step of said second exposure amount sets: said second exposure amount smaller than said first exposure amount when said luminance distribution is greater than another predetermined value.

Claim 4

The method of claim 2 , wherein said luminance distribution condition is a histogram of a relationship between a luminance value and a frequency of said first image signals at given luminance value; and said luminance distribution is a difference or a ratio of a luminance value, corresponding to A % frequency of said first image signals from the ones at the maximum luminance value, to another luminance value, corresponding to B % frequency of said first image signals from the ones at the maximum luminance value; wherein A and B satisfy 90≦A≦100 and 0≦B≦10.

Claim 5

The method of claim 2 , wherein said determining step of said gradation characteristic determines said gradation characteristic so that a gain of said gradation characteristic is larger than that of a standard gradation characteristic when said luminance distribution is smaller than a predetermined value.

Claim 6

The method of claim 2 , wherein said determining step of said gradation characteristic determines a gain of said gradation characteristic according to a prescribed condition; and wherein said gain of said gradation characteristic according to a prescribed condition is one of: a first gain larger than that of a standard gradation characteristic when said luminance distribution is smaller than said predetermined value; or a second gain not more than that of said standard gradation characteristic when said luminance distribution is smaller than said predetermined value.

Claim 7

The method of claim 1 , wherein said determining step of said second exposure amount and said gradation characteristic determines said second exposure amount and said gradation characteristic according to said luminance distribution condition so that an average luminance of luminous regions, each having distribution frequency higher than a predetermined frequency, of said image is set as a reference luminance of said second exposure amount and said gradation characteristic.

Claim 8

The method of claim 1 , wherein said determining step of said second exposure amount and said gradation determines said second exposure amount and said gradation characteristic according to said luminance distribution condition so that a luminance of a center portion of said image is set as a reference luminance of said second exposure amount and said gradation characteristic.

Claim 9

The method of claim 1 , wherein said determining step of said second exposure amount and said gradation determines said second exposure amount and said gradation characteristic according to said luminance distribution condition so that an average luminance of entire said image is set as a reference luminance of said second exposure amount and said gradation characteristic.

Claim 10

The method of claim 1 , wherein said determining step of said second exposure amount and said gradation characteristic further comprising the steps of: obtaining second image signals from said image sensor by having said image sensor detect said image with said second exposure amount; detecting another luminance distribution condition of said second image signals; determining said gradation characteristic according to said another luminance distribution condition.

Claim 11

A camera, comprising: an exposure amount determining means for determining a first exposure amount of photographing; an image sensor for converting image information to electric signals so a to obtain image signals; a detection means for detecting a luminance distribution of said image signals; said exposure amount determination means for determining a second exposure amount of photographing according to said luminance distribution; and a gradation characteristic determination means for determining a gradation characteristic of said image signals in relation to said second exposure amount of photographing; wherein said exposure amount determining means determines said second exposure amount larger than said first exposure amount when said luminance distribution is smaller than a predetermined value.

Claim 12

A camera, comprising: an exposure amount determining means for determining a first exposure amount of photographing; an image sensor for converting image information to electric signals so a to obtain image signals; a detection means for detecting a luminance distribution of said image signals; said exposure amount determination means for determining a second exposure amount of photographing according to said luminance distribution; and a gradation characteristic determination means for determining a gradation characteristic of said image signals in relation to said second exposure amount of photographing; wherein said exposure amount determining means determines said second exposure amount larger than said first exposure amount when said luminance distribution is smaller than a predetermined value.

Claim 13

The camera of claim 10 , wherein said exposure amount determination means and said gradation characteristic determination means determine said second exposure amount and said gradation characteristic respectively according to said luminance distribution condition so that an average luminance of luminous regions, each having distribution frequency higher than a predetermined frequency, of said image is set as a reference luminance of said second exposure amount and said gradation characteristic.

Claim 14

The camera of claim 10 , wherein said exposure amount determining means determines said second exposure amount smaller than said first exposure amount when said luminance distribution is greater than another predetermined value.

Claim 15

The camera of claim 12 , wherein said luminance distribution condition is a histogram of a relationship between a luminance value and a frequency of said first image signals at given luminance value; and said luminance distribution is a difference or a ratio of a luminance value, corresponding to A % frequency of said first image signals from the ones at the maximum luminance value, to another luminance value, corresponding to B % frequency of said first image signals from the ones at the maximum luminance value; wherein A and B satisfy 90≦A≦100 and 0≦B≦10.

Claim 16

The camera of claim 12 , wherein said gradation characteristic determines said gradation characteristic so that a gain of said gradation characteristic is larger than that of a standard gradation characteristic when said luminance distribution is smaller than a predetermined value.

Claim 17

The camera of claim 12 , wherein said gradation characteristic determination means determines a gain of said gradation characteristic according to a prescribed condition; and wherein said gain of said gradation characteristic according to a prescribed condition is one of: a first gain larger than that of a standard gradation characteristic when said luminance distribution is smaller than said predetermined value; or a second gain not more than that of said standard gradation characteristic when said luminance distribution is smaller than said predetermined value.

Claim 18

The camera of claim 10 , wherein said exposure amount determining means determines said second exposure amount and said gradation characteristic according to said luminance distribution condition so that a luminance of a center portion of said image is set as a reference luminance of said second exposure amount and said gradation characteristic.

Claim 19

The camera of claim 16 , further comprising: a control means for controlling said image sensor so as to output said image signals from said image sensor; wherein said control means controls said image sensor so that said image sensor outputs first image signals according to a first exposure amount, and that said image sensor outputs second image signals according to a second exposure amount after said exposure amount determination means determines said second exposure amount wherein said second exposure amount is said exposure amount of photographing.

Claim 20

The camera of claim 10 , wherein said exposure amount determining means determines said second exposure amount and said gradation characteristic according to said luminance distribution condition so that an average luminance of entire said image is set as a reference luminance of said second exposure amount and said gradation characteristic.