Exposure calculation device for a camera
First Claim
1. An exposure calculation device for a camera comprising a photometric means which performs photometry on the light from an object to be photographed and outputs a photometric signal related to the brightness thereof and a calculation means which calculates an exposure value based at least upon said photometric signal output from said photometric means, said exposure calculation device further comprising:
- a condition change-over means by which a permission condition in which it permits light from an object to be photographed to reach said photometric means and a prevention condition in which it prevents light from an object to be photographed from reaching said photometric means are switched over; and
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a storage means which stores a first photometric signal which is output by said photometric means when change to said permission condition is performed by said condition change-over means and a second photometric signal which is output by said photometric means when change to said prevention condition is performed by said condition change-over means;
wherein,said calculation means calculates said exposure value based upon the value obtained by subtracting said second photometric signal from said first photometric signal.
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Abstract
In an exposure calculation device for a camera including a photometric sensor which performs photometry on the light from an object to be photographed and outputs a photometric signal related to the brightness thereof and a calculation device which calculates an exposure value based upon the photometric signal, the calculation device calculates the exposure value based upon the value obtained by subtracting a compensation value signal from the photometric signal from the object to be photographed. This compensation value signal is the stored photometric signal obtained when a condition change-over device is in its condition to prevent light from an object to be photographed from reaching the photometric device, i.e. is the signal value due to the noise component or generated as a function of temperature.
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Citations
33 Claims
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1. An exposure calculation device for a camera comprising a photometric means which performs photometry on the light from an object to be photographed and outputs a photometric signal related to the brightness thereof and a calculation means which calculates an exposure value based at least upon said photometric signal output from said photometric means, said exposure calculation device further comprising:
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a condition change-over means by which a permission condition in which it permits light from an object to be photographed to reach said photometric means and a prevention condition in which it prevents light from an object to be photographed from reaching said photometric means are switched over; and
;a storage means which stores a first photometric signal which is output by said photometric means when change to said permission condition is performed by said condition change-over means and a second photometric signal which is output by said photometric means when change to said prevention condition is performed by said condition change-over means;
wherein,said calculation means calculates said exposure value based upon the value obtained by subtracting said second photometric signal from said first photometric signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An exposure calculation device for a camera comprising a photometric means which performs photometry on the light from an object to be photographed and outputs a photometric signal related to the brightness thereof and a calculation means which calculates an exposure value based at least upon said photometric signal output from said photometric means, said exposure calculation device further comprising:
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a temperature detection means which detects the temperature in the camera; and
;a noise component value detection means which obtains the value of the noise component in said photometric signal corresponding to the temperature detected by said temperature detection means;
wherein,said calculation means calculates said exposure value based upon the value obtained by subtracting said noise component value obtained by said noise component value detection means from said photometric signal output from said photometric means. - View Dependent Claims (10, 11)
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12. An exposure calculation device for a camera comprising a photometric means which performs photometry on a plurality of divided regions to which the light from an object to be photographed is incident and outputs a photometric signal related to the brightness of said region, and a calculation means which calculates an exposure value based at least upon said photometric signals output from said photometric means, said exposure calculation device further comprising:
a classification means which quantizes at a predetermined resolution the photometric signals obtained by performing photometry upon an object to be photographed having a uniform brightness, and then classifies said plurality of regions into a plurality of groups of regions each having the same quantized photometric signal value; and
;a storage means which, for each of said groups of regions classified by said classification means, stores one compensation value corresponding to the magnitude of said photometric signal;
wherein,said calculation means compensates according to said compensation values the photometric signals obtained by performing photometry by said photometric means for an object to be photographed, and calculates an exposure value based upon said photometric signals after compensation. - View Dependent Claims (13, 14, 15)
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16. An exposure calculation device for a camera comprising a photometric means which performs photometry on a plurality of divided regions to which the light from an object to be photographed is incident and outputs a photometric signal related to the brightness of said region and a calculation means which calculates an exposure value based at least upon said photometric signal output from said photometric means, said exposure calculation device further comprising:
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storage means which stores compensation values for each of said photometry outputs, said compensation values assigned to a plurality of groups of regions into which said plurality of regions are classified, each of said regions in the same group having the same characteristics, in accordance with characteristic difference between individual ones of the photometry outputs from said plurality of regions, wherein said calculation means compensates said photometry signal obtained by performing photometry on an object to be photographed by said photometry means according to said compensation value, said compensation value being assigned to the group including the region from which said photometry signal is outputted and stored in said storage means for each regions, said calculation means calculates an exposure value in accordance with the photometry signal thus compensated. - View Dependent Claims (17)
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18. An exposure calculation device for a camera comprising a photometric means which performs photometry on a plurality of divided regions to which the light from an object to be photographed is incident, and outputs a photometric signal related to the brightness of said region, and a calculation means which calculates an exposure value based at least upon said photometric signals output from said photometric means, said exposure calculation device further comprising:
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a compensation means which decides whether or not said plurality of photometric signals includes an excessive value signal having a brightness higher than a predetermined value, and which performs, when said plurality of photometric signals does include such an excessive value signal having a brightness higher than a predetermined value, compensation by reducing the values of said excessive value signal and of the signals from a plurality of regions in the neighborhood of the region corresponding to said excessive value signal by predetermined amounts;
wherein,said calculation means calculates an exposure value based upon the values of said photometric signals after compensation by said compensation means. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. An exposure calculation apparatus for a camera comprising a photometric member, which performs photometry on the light from an object to be photographed and outputs a photometric signal related to the brightness thereof, and a calculation device, which calculates an exposure value based at least upon said photometric signal output from said photometric member, said exposure calculation apparatus further comprising:
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a condition change-over device that switches between a permission condition in which light from an object to be photographed is permitted to reach said photometric member and a prevention condition in which light from an object to be photographed is prevented from reaching said photometric member; and a storage device that stores a first photometric signal output by said photometric member when said condition change-over device switches to said permission condition and a second photometric signal output by said photometric member when said condition change-over device switches to said prevention condition, wherein said calculation device calculates said exposure value based upon the value obtained by subtracting said second photometric signal from said first photometric signal.
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30. An exposure calculation apparatus for a camera comprising a photometric member, which performs photometry on the light from an object to be photographed and outputs a photometric signal related to the brightness thereof, and a calculation device, which calculates an exposure value based at least upon said photometric signal output from said photometric member, said exposure calculation apparatus further comprising:
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a temperature detection device that detects the temperature in the camera; and a noise component value detection device that obtains the value of the noise component in said photometric signal corresponding to the temperature detected by said temperature detection device, wherein said calculation device calculates said exposure value based upon the value obtained by subtracting said noise component value obtained by said noise component value detection device from said photometric signal output from said photometric member.
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31. An exposure calculation apparatus for a camera comprising a photometric member, which performs photometry on a plurality of divided regions to which the light from an object to be photographed is incident and outputs a photometric signal related to the brightness of said region, and a calculation device, which calculates an exposure value based at least upon said photometric signals output from said photometric member, said exposure calculation apparatus further comprising:
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a classification device that quantizes at a predetermined resolution the photometric signals obtained by performing photometry upon an object to be photographed having a uniform brightness, and then classifies said plurality of regions into a plurality of groups of regions each having the same quantized photometric signal value; and a storage device that, for each of said groups of regions classified by said classification device, stores one compensation value corresponding to the magnitude of said photometric signal, wherein said calculation device compensates according to said compensation values the photometric signals obtained by performing photometry by said photometric member for an object to be photographed and calculates an exposure value based upon said photometric signals after compensation.
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32. An exposure calculation apparatus for a camera comprising a photometric member, which performs photometry on a plurality of divided regions to which the light from an object to be photographed is incident and outputs a photometric signal related to the brightness of said region, and a calculation device, which calculates an exposure value based at least upon said photometric signals output from said photometric member, said exposure calculation apparatus further comprising:
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storage device that stores compensation values for each of said output photometry signals, said compensation values assigned to a plurality of groups of regions into which said plurality of regions are classified, each of said regions in the same group having the same characteristics, in accordance with characteristic difference between individual ones of the output photometry signals from said plurality of regions, wherein said calculation device compensates said photometry signal obtained by performing photometry on an object to be photographed by said photometric member according to said compensation value, said compensation value being assigned to the group including the region from which said photometry signal is outputted and stored in said storage device for each region, and said calculation device calculates an exposure value in accordance with the photometry signal thus compensated.
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33. An exposure calculation apparatus for a camera comprising a photometric member, which performs photometry on a plurality of divided regions to which the light from an object to be photographed is incident and outputs a photometric signal related to the brightness of said region, and a calculation device, which calculates an exposure value based at least upon said photometric signals output from said photometric member, said exposure calculation apparatus further comprising:
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a compensation device that decides whether said plurality of photometric signals includes an excessive value signal having a brightness higher than a predetermined value, and that performs, when said plurality of photometric signals does include such an excessive value signal having a brightness higher than a predetermined value, compensation by reducing the values of said excessive value signal and of the signals from a plurality of regions in the neighborhood of the region corresponding to said excessive value signal by predetermined amounts, wherein said calculation device calculates an exposure value based upon the values of said photometric signals after compensation by said compensation device.
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Specification