Photographing control apparatus and method
A photographing control apparatus that controls a sensor for accumulating and reading out electric charge in order to obtain an image, includes: a deciding unit adapted to decide a frame period showing an image photographing interval, based on an input of an input unit; a determining unit adapted to determine, based on the frame period decided by the deciding unit, whether accumulation and reading out of electric charge not for use in an image generating process is set in the frame period; and a control unit adapted to control the sensor based on the determination by the determining unit.
1. A photographing control apparatus that controls a sensor for accumulating and reading out electric charge in order to obtain an image, comprising:
a deciding unit adapted to decide a frame period showing an image photographing interval, based on an input of an input unit;
a determining unit adapted to determine, based on the frame period decided by the deciding unit, whether accumulation and reading out of electric charge not for use in an image generating process is set in the frame period; and
a control unit adapted to control the sensor based on the determination by the determining unit.
2. The photographing control apparatus according to claim 1 , wherein the determining unit includes:
a calculating unit adapted to calculate a first accumulation period during which electric charge for obtaining the image is accumulated, based on the frame period decided by the deciding unit;
a comparing unit adapted to compare the first accumulation period with a reference period constituting a reference; and
a changing unit adapted to set accumulation and reading out of electric charge not for use in the image generating process, and change the first accumulation period to a second accumulation period that is shorter than the first accumulation period, if it is determined by the comparing unit that the first accumulation period is greater than the reference period.
3. The photographing control apparatus according to claim 2 , wherein the first accumulation period is a charge accumulation period for when accumulation and reading out of electric charge are alternately performed repeatedly.
4. The photographing control apparatus according to claim 3 , wherein
the sensor detects irradiated radiation as electric charge, and
in a case where accumulation and reading out of electric charge when radiation is irradiated is performed once, and accumulation and reading out of electric charge when radiation is not irradiated is repeated k−1 times, with a number of the repetitions in the frame period being a positive integer, the changing unit sets an accumulation period of electric charge not for use in the image generating process so that,
Tw 2= Tf 10−( k·Tw 1+( k+ 1)· Tr ), and
Tw1>Tx
are satisfied, where Tx is an irradiation period of radiation, Tr is a readout period related to reading out of electric charge, Tf 10 is the frame period, Tw 1 is the second accumulation period, and Tw 2 is the accumulation period of electric charge not for use in the image generating process.
5. The photographing control apparatus according to claim 4 , wherein the reference period is,
Tc=Tx+Tr/k
where Tc is the reference period.
6. The photographing control apparatus according to claim 4 , wherein the calculating unit calculates the first accumulation period using,
Tw 11= Tf 10/ k−Tr
where Tw 11 is the first accumulation period.
7. The photographing control apparatus according to claim 3 , wherein in a case where accumulation and reading out of electric charge when a first radiation is irradiated, accumulation and reading out of electric charge when a second radiation is irradiated, and accumulation and reading out of electric charge when radiation is not irradiated are performed as the repetition in the frame period, the changing unit sets an accumulation period of electric charge not for use in the image generating process so that,
Tw 6= Tf 12−(2 Tw 5+3 Tr ), and
Tw5>Tx
are satisfied, where Tx is an irradiation period of the first radiation and the second radiation, Tr is a readout period related to reading out of electric charge, Tf 12 is the frame period, Tw 5 is the second accumulation period, and Tw 6 is the accumulation period of electric charge not for use in the image generating process.
8. The photographing control apparatus according to claim 7 , wherein the reference period is,
Tc=Tx+Tr/ 3
where Tc is the reference period.
9. The photographing control apparatus according to claim 7 , wherein the calculating unit calculates the first accumulation period using,
Tw 15= Tf 12/3− Tr
where Tw 15 is the first accumulation period.
10. The photographing control apparatus according to claim 3 , wherein in a case where accumulation and reading out of electric charge when a first radiation is irradiated, accumulation and reading out of electric charge when radiation is not irradiated, accumulation and reading out of electric charge when a second radiation is irradiated, and accumulation and reading out of electric charge when radiation is not irradiated are performed as the repetition in the frame period, the changing unit sets an accumulation period of electric charge not for use in the image generating process so that,
Tw 9= Tf 13−(2·( Tw 7+ Tw 8)+5 Tr ), and
Tw7>Txl, Tw8>Txh
are satisfied, where Txl is an irradiation period of the first radiation, Txh is an irradiation period of the second radiation, Tr is a readout period related to reading out of electric charge, Tf 13 is the frame period, Tw 7 is the second accumulation period when the first radiation is irradiated, Tw 8 is the second accumulation period when the second radiation is irradiated, and Tw 9 is the accumulation period of electric charge not for use in the image generating process.
11. The photographing control apparatus according to claim 10 , wherein the reference period is,
Tc 1= Txl+Tr/ 4, and
Tc 2= Txh+Tr/ 4,
where Tc 1 is the reference period in a case of the first irradiation, and Tc 2 is the reference period in a case of the second irradiation.
12. The photographing control apparatus according to claim 10 , wherein the calculating unit calculates the first accumulation period using,
Tw 18= Tf 13/4− Tr+ ( Txl−Txh )/2, and
Tw 20= Tf 13/4 −Tr+ ( Txh−Txl )/2
where Tw 18 is the first accumulation period in a case of the first radiation, and Tw 20 is the first accumulation period in a case of the second radiation.
13. The photographing control apparatus according to claim 12 , the comparing unit compares,
Tc1>Tw18, and
Tc2>Tw20.
14. The photographing control apparatus according to claim 7 , wherein the first radiation results from a low voltage and the second radiation results from a high voltage.
15. A control method of a photographing control apparatus that controls a sensor for accumulating and reading out electric charge in order to obtain an image, comprising the steps of:
deciding a frame period showing an image photographing interval, based on an input of an input unit;
determining, based on the frame period decided by the deciding step, whether accumulation and reading out of electric charge not for use in an image generating process is set in the frame period; and
controlling the sensor based on the determination in the determining step.
16. A computer program of instructions stored in a computer-readable medium, the program causing a computer to perform a method comprising the steps of:
deciding a frame period showing an image photographing interval, based on an input of an input unit;
determining, based on the frame period decided by the deciding step, whether accumulation and reading out of electric charge not for use in an image generating process is set in the frame period; and
controlling a sensor based on the determination in the determining step.