Patent Number: 
Section: claims

1. An imaging apparatus comprising: an image sensing unit adapted for sensing an electromagnetic wave image of a subject; and  a controller adapted for generating a first signal for permitting an irradiating unit to irradiate an electromagnetic wave and a second signal for initializing said image sensing unit, so as to overlap a first period and a second period,  wherein the first period is an interval between a timing when the first signal is outputted from said controller and a timing when the electromagnetic wave is outputted from said irradiating unit, and  wherein the second period is an interval between a timing when the second signal is outputted from said controller and a timing when the initialization of said image sensing unit has been completed. 2. An apparatus according to  claim 1 , wherein said controller controls so that one of the first signal and the second signal starts after the other has started and before it has stopped. claim 1 3. An apparatus according to  claim 1 , wherein said image sensing unit has a photo-electric conversion device which outputs a signal in accordance with an electromagnetic wave and the second period is an interval between a timing when the second signal, for initializing said photo-electric conversion device, is outputted from said controller and a timing when the initialization of said photo-electric conversion device has been completed. claim 1 4. An apparatus according to  claim 3 , wherein the second period is an interval for a pre-discharge of said photo-electric conversion device. claim 3 5. An apparatus according to  claim 1 , wherein said image sensing unit has a grid which absorbs scattered rays from the subject, and said controller generates a third signal for driving said grid so as to overlap the first, the second and a third period, wherein the third period is an interval between a timing when the third signal is outputted from said controller and a timing when the initialization of said grid has been completed. claim 1 6. An apparatus according to  claim 5 , wherein the initialization of said grid is that a position and a moving speed of said grid should reach a target. claim 5 7. An apparatus according to  claim 1 , wherein said image sensing unit has a photo-electric conversion device which outputs a signal in accordance with an electromagnetic wave and a grid which absorbs scattered rays from the subject, and said controller generates a third signal for driving said grid so as to overlap the first, the second and a third period, wherein the third period is an interval between a timing when the third signal is outputted from said controller and a timing when the initialization of said grid has been completed. claim 1 8. An apparatus according to  claim 1 , wherein said controller generates the first signal so that an irradiation of the electromagnetic wave starts at a timing when a fourth period is elapsed after said controller has received a fourth signal which instructs a start of imaging, the fourth period being the longer one of the first and second period. claim 1 9. An apparatus according to  claim 5 , wherein said controller generates the first signal so that an irradiation of the electromagnetic wave starts at timing when a fourth period is elapsed after said controller has received a fourth signal which instructs a start of imaging, the fourth period being the longest one of the first, second and third period. claim 5 10. An imaging system comprising: an irradiating unit adapted for irradiating an electromagnetic wave;  an image sensing unit adapted for sensing an electromagnetic wave image of a subject using the electromagnetic wave; and  a controller adapted for generating a first signal for permitting said irradiating unit to irradiate the electromagnetic wave and a second signal for initializing said image sensing unit, so as to overlap a first period and a second period,  wherein the first period is an interval between a timing when the first signal is outputted from said controller and a timing when the electromagnetic wave is outputted from said irradiating unit, and  wherein the second period is an interval between a timing when the second signal is outputted from said controller and a timing when the initialization of said image sensing unit has been completed. 11. A method adapted to an imaging apparatus including an image sensing unit adapted for sensing an electromagnetic wave image of a subject, comprising a step of: controlling a controller to generate a first signal for permitting an irradiating unit to irradiate an electromagnetic wave and a second signal for initializing the image sensing unit, so as to overlap a first period and a second period,  wherein the first period is an interval between a timing when the first signal is outputted from the controller and a timing when the electromagnetic wave is outputted from the irradiating unit, and  wherein the second period is an interval between a timing when the second signal is outputted from the controller and a timing when the initialization of the image sensing unit has been completed. 12. A method according to  claim 11 , wherein in said controlling step, one of the first signal and the second signal is started after the other has started and before it has stopped. claim 11 13. A method according to  claim 11 , wherein the image sensing unit has a photo-electric conversion device which outputs a signal in accordance with an electromagnetic wave and the second period is an interval between a timing when the second signal, for initializing the photo-electric conversion device, is outputted from the controller and a timing when the initialization of the photo-electric conversion device has been completed. claim 11 14. A method according to  claim 13 , wherein the second period is an interval for a pre-discharge of the photo-electric conversion device. claim 13 15. A method according to  claim 11 , wherein the image sensing unit has a grid which absorbs scattered rays from the subject, and said controlling step includes controlling the controller to generate a third signal for driving the grid so as to overlap the first, the second and a third period, wherein the third period is an interval between a timing when the third signal is outputted from the controller and a timing when an initialization of the grid has been completed. claim 11 16. A method according to  claim 15 , wherein the initialization of the grid is that a position and a moving speed of the grid should reach a target. claim 15 17. A method according to  claim 11 , wherein the image sensing unit has a photo-electric conversion device which outputs a signal in accordance with an electromagnetic wave and a grid which absorbs scattered rays from the subject, and said controlling step includes controlling the controller to generate a third signal for driving the grid so as to overlap the first, the second and a third period, wherein the third period is an interval between a timing when the third signal is outputted from the controller and a timing when an initialization of said grid has been completed. claim 11 18. A method according to  claim 11 , wherein in said controlling step, the first signal is generated so that an irradiation of the electromagnetic wave starts at a timing when a fourth period is elapsed after the controller has received a fourth signal which instructs a start of imaging, the fourth period being the longer one of the first and second period. claim 11 19. A method according to  claim 15 , wherein in said controlling step, the first signal is generated so that an irradiation of the electromagnetic wave starts at a timing when a fourth period is elapsed after the controller has received a fourth signal which instructs a start of imaging, the fourth period being the longest one of the first, second and third period. claim 15 20. A computer-readable storage medium which stores a program for executing a method adapted to an imaging apparatus including an image sensing unit adapted for sensing an electromagnetic wave image of a subject, the method comprising a step of: controlling a controller to generate a first signal for permitting an irradiating unit to irradiate an electromagnetic wave and a second signal for initializing the image sensing unit, so as to overlap a first period and a second period,  wherein the first period is an interval between a timing when the first signal is outputted from the controller and a timing when the electromagnetic wave is outputted from the irradiating unit, and  wherein the second period is an interval between a timing when the second signal is outputted from the controller and a timing when the initialization of the image sensing unit has been completed. 21. An imaging apparatus comprising: an irradiating unit for irradiating an electromagnetic wave:  a grid which is arranged in irradiating path of the electromagnetic wave;  a grid moving unit for moving said grid in the irradiating path;  an image sensing unit for converting the electromagnetic wave to image data, said image sensing unit having a plurality of image sensing elements;  a storage device for storing combinations of a first time interval which is a time interval between a timing when an irradiation permission signal is sent to said irradiating unit and a timing when an irradiation starts, a second time interval which is a time interval between a timing when said grid moving unit starts driving of said grid and a timing when said grid reaches a target position and a target speed, and a third time interval in which said image sensing unit is initialized, so that each of the combinations of the first time interval, the second time interval and the third time interval corresponds to each of a plurality of image sensing conditions;  an image sensing condition instructing device for inputting an image sensing condition; and  a controller for controlling said irradiating unit, said grid moving unit and said image sensing unit,  wherein, said controller selects a combination of the first time interval, the second time interval and the third time interval corresponding to the image sensing condition instructed by said image sensing condition instructing device, and controls so that a timing when said irradiating unit starts an irradiation, a timing when said grid reaches the target position and the target speed, and a timing when an initialization driving of said image sensing unit is completed coincide with each other, based an the selected combination. 22. An apparatus according to  claim 21 , wherein said controller transmits the irradiation permission signal, a driving start signal of said grid moving unit and a start signal of the initialization driving at a timing for coincidence of a timing when said irradiating unit starts an irradiation, a timing when said grid reaches the target position and the target speed, and a timing when an initialization driving of said image sensing unit is completed. claim 21 23. An apparatus according to  claim 21 , further comprising an image sensing instruction unit for inputting an image sensing request signal, wherein said controller controls so that a longest time in the first time interval, the second time interval and the third time interval corresponding to the image sensing condition instructed by said image sensing condition instructing device coincide with a time interval between a timing when the image sensing request signal is inputted and a timing when said irradiating unit starts irradiation. claim 21 24. An apparatus according to  claim 21 , wherein said controller controls to stop a moving control of said grid moving unit after an actual irradiation time is elapsed from the timing when said irradiating unit starts an irradiation, and to start reading of a signal from said image sensing unit after a predetermined time elapsed from the timing when the moving control has been stopped. claim 21 25. An apparatus according to  claim 21 , further comprising an electromagnetic wave detecting device for detecting an amount of the electromagnetic wave, wherein said controller controls to stop a moving control of said grid moving unit based on an output signal of said electromagnetic wave detecting device. claim 21 26. An imaging apparatus comprising: an irradiating unit for irradiating an electromagnetic wave;  an image sensing unit for converting the electromagnetic wave to image data, said image sensing unit having a plurality of image sensing elements;  a storage device for storing combinations of a first time interval which is a time interval between a timing when an irradiation permission signal is sent to said irradiating unit and a timing when an irradiation starts, and a second time interval in which said image sensing unit is initialized, so that each of the combinations of the first time interval and the second time interval corresponds to each of a plurality of image sensing conditions;  an image sensing condition instructing device for inputting an image sensing condition: and  a controller for controlling said irradiating unit and said image sensing unit,  wherein, said controller selects a combination of the first time interval and the second time interval corresponding to the image sensing condition instructed by said image sensing condition instructing device, and controls so that a timing when said irradiating unit starts an irradiation and a timing when an initialization driving of said image sensing unit is completed coincide with each other, based on the selected combination. 27. An apparatus according to  claim 26 , wherein said controller transmits the irradiation permission signal and a start signal of the initialization driving at a timing for coincidence of a timing when said irradiating unit starts an irradiation and a timing when an initialization driving of said image sensing unit is completed. claim 26 28. An imaging apparatus comprising: a grid which is arranged in irradiating path of the electromagnetic wave;  a grid moving unit for moving said grid in the irradiating path;  an image sensing unit for converting the electromagnetic wave to image data, said image sensing unit having a plurality of image sensing elements;  a storage device for storing combinations of a first time interval which is a time interval between a timing when said grid moving unit starts driving of said grid and a timing when said grid reaches a target position and target speed, and a second time interval in which said image sensing unit is initialized, so that each of the combinations of the first time interval and the second time interval corresponds to each of a plurality of image sensing conditions;  an image sensing condition instructing device for inputting an image sensing condition; and  a controller for controlling said grid moving unit and said image sensing unit,  wherein, said controller selects a combination of the first time interval and the second time interval corresponding to the image sensing condition instructed by said image sensing condition instructing device, and controls so that a timing when said grid reaches the target position and the target speed and a timing when an initialization driving of said image sensing unit is complete coincide with each other, based on the selected combination. 29. An apparatus according to  claim 28 , wherein said controller transmits a driving start signal of said grid moving unit and a start signal of the initialization driving at a timing for coincidence of a timing when said grid reaches the target position and the target speed and a timing when an initialization driving of said image sensing unit is completed. claim 28