JP2010028856A - Imaging method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus and imaging method capable of reducing costs of the imaging apparatus by reducing storage capacity of a memory by reading images within an imaging range corresponding to a zoom magnification from a solid-state imaging device during digital zooming. <P>SOLUTION: During digital zooming, a digital zoom setting section 22 sets a vertical imaging range of a CMOS image sensor 13 in accordance with a zoom magnification, and the CMOS image sensor 13 performs imaging within the set imaging range. When the zoom magnification is changed, a maximum exposure time of the CMOS image sensor 13 is arithmetically operated on the basis of zoom magnifications before and after the change in such a manner that a shutter signal after the change does not interfere with a read signal before the change, and an exposure time of the CMOS image sensor 13 is set so as not to exceed the arithmetically operated maximum exposure time. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image pickup apparatus and an image pickup method for performing digital zoom for enlarging an image picked up by an XY address type solid-state image pickup device.

  2. Description of the Related Art An imaging device that performs digital zoom for enlarging an image captured by a solid-state imaging device, such as a video camera, a digital camera, and an imaging unit of a mobile phone, is known. In a conventional imaging device, an image captured by a solid-state imaging device is stored in a memory, and then an image in a zoom range is cut out and enlarged (see Patent Documents 1 and 2).

JP 2003-179799 A JP 2003-153078 A

  However, in the conventional imaging device, the image captured by the solid-state imaging device is stored in the memory, and then the image in the zoom range is cut out and subjected to the enlargement process. Therefore, the storage capacity of the memory increases, which results in the cost of the imaging device There was a problem that became high.

  The present invention has been made in view of such circumstances, and its purpose is to reduce the storage capacity of the memory by reading an image in the imaging range corresponding to the zoom magnification from the solid-state image sensor during the digital zoom operation. Thus, an imaging apparatus and an imaging method that can reduce the cost of the imaging apparatus are provided.

In the first imaging method of the present invention, an exposure time is controlled by a shutter signal for starting exposure and a readout signal for ending exposure that scan a plurality of pixels arranged in a matrix in the vertical direction. When the exposure time setting step for setting the exposure time of the address type solid-state image sensor and the digital zoom operation mode for enlarging the image captured by the solid-state image sensor are selected, the zoom magnification is set, and the set zoom magnification is set. And a digital zoom step of enlarging an image captured by the solid-state image sensor, wherein the imaging range is set in the vertical direction of the solid-state image sensor in accordance with the zoom magnification set in the digital zoom step. The exposure of the imaging range set in the range setting step and the imaging range setting step is set in the exposure time setting step. A driving step for driving the solid-state imaging device by outputting a driving signal for scanning the shutter signal and the readout signal so that the exposure time is set, and the exposure time setting step includes a zoom magnification in the digital zoom step. Is changed so that the shutter signal that scans the imaging range according to the zoom magnification after the change does not interfere with the readout signal that scans the imaging range according to the zoom magnification before the change. A calculation step of calculating a maximum exposure time of the solid-state imaging device based on a zoom magnification, and setting the exposure time of the solid-state imaging device so as not to exceed the maximum exposure time calculated in the calculation step; To do.

The first imaging device of the present invention scans a plurality of pixels arranged in a matrix and a shutter signal for discharging accumulated signal charges and starting exposure in units of rows in the vertical direction of the plurality of pixels. A shutter scanning circuit; and a readout scanning circuit that scans a readout signal for reading out the accumulated signal charges after completion of exposure in the vertical direction of the plurality of pixels, by the shutter signal and the readout signal. An XY address type solid-state imaging device whose exposure time is controlled, an exposure time setting means for setting the exposure time of the solid-state imaging device, and a digital zoom operation mode for enlarging an image captured by the solid-state imaging device are selected. And a digital zoom means for setting a zoom magnification and enlarging an image picked up by the solid-state image sensor at the set zoom magnification. An imaging apparatus, an imaging range setting unit that sets an imaging range in a vertical direction of the solid-state imaging device according to a zoom magnification set by the digital zoom unit, and exposure of an imaging range set by the imaging range setting unit Driving means for driving the solid-state imaging device by outputting a drive signal for scanning the shutter signal and the readout signal so as to perform the exposure time set by the exposure time setting means, and the exposure time setting means When the zoom magnification is changed by the digital zoom means, the shutter signal that scans the imaging range according to the changed zoom magnification does not interfere with the readout signal that scans the imaging range according to the zoom magnification before the change. To calculate the maximum exposure time of the solid-state imaging device based on the zoom magnification before and after the change Has a step, and setting the solid exposure time of the image pickup device so as not to exceed the maximum exposure time calculated by said calculating means.

Further, in the second imaging method of the present invention, the exposure time is controlled by a shutter signal for starting exposure and a readout signal for ending exposure that scan a plurality of pixels arranged in a matrix in the vertical direction. -Digital zoom for setting a zoom magnification when a digital zoom operation mode for enlarging an image captured by a Y address type solid-state image sensor is selected, and enlarging an image captured by the solid-state image sensor at the set zoom magnification An imaging method including a step, wherein when the digital zoom operation mode is selected, the maximum exposure time of the solid-state image sensor is set to a predetermined time shorter than the vertical scanning period of the readout signal, and the set maximum exposure time is set The exposure time setting step for setting the exposure time of the solid-state imaging device so as not to exceed, and the digital zoom step. An imaging range setting step for setting the imaging range in the vertical direction of the solid-state imaging device according to the zoom magnification that has been set, and an exposure set in the exposure time setting step for exposure of the imaging range set in the imaging range setting step A drive signal for scanning the shutter signal and the readout signal so as to be performed in time, and a drive step for driving the solid-state imaging device, wherein the digital zoom step is performed after the change when the zoom magnification is changed. Based on the maximum exposure time set in the exposure time setting step so that the shutter signal that scans the imaging range according to the zoom magnification does not interfere with the readout signal that scans the imaging range according to the zoom magnification before the change. A maximum change rate setting step for setting a maximum change rate of the zoom magnification, and the maximum change rate setting step And wherein the changing the zoom magnification so as not to exceed the maximum rate of change set.

Further, the second imaging device of the present invention scans a plurality of pixels arranged in a matrix and a shutter signal for discharging accumulated signal charges and starting exposure in units of rows in the vertical direction of the plurality of pixels. A shutter scanning circuit; and a readout scanning circuit that scans a readout signal for reading out the accumulated signal charges after completion of exposure in the vertical direction of the plurality of pixels, by the shutter signal and the readout signal. When an XY address type solid-state imaging device whose exposure time is controlled and a digital zoom operation mode for enlarging an image captured by the solid-state imaging device are selected, the zoom magnification is set, and the set zoom magnification is set. An image pickup apparatus comprising: a digital zoom means for enlarging an image picked up by the solid-state image pickup device; and a motion for operating the digital zoom means. When the mode is selected, the maximum exposure time of the solid-state image sensor is set to a predetermined time shorter than the vertical scanning period of the readout signal, and the exposure time of the solid-state image sensor is set so as not to exceed the set maximum exposure time. An exposure time setting means for setting, an imaging range setting means for setting an imaging range in the vertical direction of the solid-state imaging device according to a zoom magnification set by the digital zoom means, and an imaging range set by the imaging range setting means A shutter driving signal for scanning the shutter signal by the shutter scanning circuit and a reading driving signal for scanning the reading signal by the reading scanning circuit so that the exposure is performed at the exposure time set by the exposure time setting means. Driving means for driving the solid-state imaging device, and the digital zoom means When the magnification is changed, the exposure time setting is performed so that a shutter signal that scans the imaging range according to the zoom magnification after the change does not interfere with a readout signal that scans the imaging range according to the zoom magnification before the change. A maximum change rate setting means for setting the maximum change rate of the zoom magnification based on the maximum exposure time set by the means, and the zoom magnification is set so as not to exceed the maximum change rate set by the maximum change rate setting means. It is characterized by changing.

According to the first imaging method and imaging apparatus of the present invention, the imaging range in the vertical direction of the solid-state imaging device is set according to the zoom magnification of the digital zoom, and the exposure of the set imaging range is performed with the set exposure time. In this manner, the solid-state imaging device is driven by scanning the shutter signal and the readout signal. When the zoom magnification is changed, the shutter signal that scans the imaging range according to the zoom magnification after the change is not changed so as not to interfere with the readout signal that scans the imaging range according to the zoom magnification before the change. The maximum exposure time of the solid-state image sensor is calculated based on the zoom magnification after the change, and the exposure time of the solid-state image sensor is set so as not to exceed the calculated maximum exposure time.
Accordingly, since an image in the imaging range corresponding to the zoom magnification can be read from the solid-state imaging device, the capacity of the memory for storing the read image can be reduced, thereby reducing the cost of the imaging apparatus. Further, when the zoom magnification is changed, the shutter signal that scans the imaging range according to the zoom magnification after the change does not interfere with the readout signal that scans the imaging range according to the zoom magnification before the change. And the maximum exposure time of the solid-state image sensor is calculated based on the zoom magnification after the change, and the exposure time of the solid-state image sensor is set so as not to exceed the calculated maximum exposure time, so even if the zoom magnification changes, It is possible to capture a normal image without any disturbance by the solid-state imaging device.

According to the second imaging method and imaging apparatus of the present invention, when the digital zoom operation mode is selected, the maximum exposure time of the solid-state imaging device is set to a predetermined time shorter than the vertical scanning period of the readout signal. The exposure time of the solid-state image sensor is set so as not to exceed the maximum exposure time, the vertical imaging range of the solid-state image sensor is set according to the set zoom magnification, and the exposure of the set imaging range is set The solid-state imaging device is driven by scanning the shutter signal and the readout signal so as to perform the exposure time. Then, when the zoom magnification is changed, the maximum signal is set so that the shutter signal that scans the imaging range according to the zoom magnification after the change does not interfere with the readout signal that scans the imaging range according to the zoom magnification before the change. A maximum zoom magnification change rate is set based on the exposure time, and the zoom magnification is changed so as not to exceed the set maximum change rate.
Accordingly, since an image in the imaging range corresponding to the zoom magnification can be read from the solid-state imaging device, the capacity of the memory for storing the read image can be reduced, thereby reducing the cost of the imaging apparatus. In addition, when the zoom magnification is changed, the maximum signal is set so that the shutter signal that scans the imaging range according to the zoom magnification after the change does not interfere with the readout signal that scans the imaging range according to the zoom magnification before the change. The maximum change rate of the zoom magnification is set based on the exposure time, and the zoom magnification is changed so as not to exceed the set maximum change rate, so even if the zoom magnification changes, the solid-state image sensor does not disturb the normal An image can be taken.

1 is a diagram illustrating a schematic configuration of an imaging apparatus according to Embodiment 1. FIG. It is a figure which shows the structure of the CMOS image sensor 13 shown by FIG. FIG. 6 is a diagram illustrating an operation of the CMOS image sensor 13. FIG. 6 is a diagram illustrating an operation of the CMOS image sensor 13. FIG. 6 is a diagram illustrating an operation of the CMOS image sensor 13. FIG. 6 is a diagram illustrating an operation of the CMOS image sensor 13. It is a figure which shows interference with a read signal and a shutter signal. It is a figure which shows an example of the maximum exposure time when a digital zoom magnification is changed. FIG. 10 is a diagram illustrating a configuration of a CMOS image sensor of an imaging apparatus according to a fifth embodiment. It is a figure which shows the problem of the interference between shutter signals. FIG. 10 is a diagram illustrating a configuration of a CMOS image sensor of an imaging apparatus according to a sixth embodiment. FIG. 10 is a diagram illustrating a configuration of a CMOS image sensor of an imaging apparatus according to a seventh embodiment.

To achieve the above object, the present invention scans a plurality of pixels arranged in a matrix, a shutter signal for starting the exposure discharges the signal charges accumulated in the row in the vertical direction of the plurality of pixels shutters A scanning circuit for scanning, and a scanning signal scanning circuit that scans a readout signal for reading the accumulated signal charge after completion of exposure in the vertical direction of the plurality of pixels, and is exposed by the shutter signal and the readout signal. An XY address type solid-state imaging device in which time is controlled is used. When the digital zoom operation mode is selected, the imaging range in the vertical direction of the solid-state imaging device is set according to the zoom magnification of the digital zoom, and the shutter signal and readout are performed so that the exposure of the set imaging range is performed with the set exposure time. The solid-state image sensor is driven by scanning the signal. When the zoom magnification is changed, the shutter signal that scans the imaging range according to the zoom magnification after the change is not changed so as not to interfere with the readout signal that scans the imaging range according to the zoom magnification before the change. The maximum exposure time of the solid-state image sensor is calculated based on the zoom magnification after the change, and the exposure time of the solid-state image sensor is set so as not to exceed the calculated maximum exposure time.

Hereinafter, an imaging apparatus and an imaging method according to a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram illustrating a schematic configuration of the imaging apparatus according to the first embodiment.
As shown in FIG. 1, the imaging apparatus according to the first embodiment includes a lens 11, an iris 12, a CMOS image sensor 13, a signal processing circuit 14, an image memory 15, an operation unit 16, a display unit 17, a recording medium 18, and a control circuit 19. Is provided.

  The lens 11 is formed of a zoom lens, for example, and forms an image of the subject on the CMOS image sensor 13. The lens 11 is not limited to a zoom lens, and may be a single focus lens, for example. The iris 12 adjusts the aperture amount and serves as a mechanical shutter. The CMOS image sensor 13 images the subject imaged by the lens 11. The solid-state image sensor is not limited to a CMOS image sensor, and may be an XY address type solid-state image sensor.

  The signal processing circuit 14 performs various signal processing on the image captured by the CMOS image sensor 13. The signal processing circuit 14 includes a digital zoom processing unit 21 that enlarges an image captured by the CMOS image sensor 13. The image memory 15 stores an image captured by the CMOS image sensor 13 and converted into a digital signal by the signal processing circuit 14. The image memory 15 is used for signal processing of the signal processing circuit 14. The operation unit 16 includes an operation button, an operation lever, and the like (not shown) for inputting various types of operation information. The display unit 17 includes, for example, a liquid crystal display, and displays an output image of the signal processing circuit 14 and information on the imaging device. The recording medium 18 includes, for example, a replaceable magnetic tape, an optical disk, and a memory card, and records an output image of the signal processing circuit 14.

  The control circuit 19 controls the lens 11, the iris 12, the CMOS image sensor 13, the signal processing circuit 14, the image memory 15 and the display unit 17 based on the operation information input from the operation unit 16. The control circuit 19 includes a digital zoom setting unit 22, an imaging condition setting unit 23, a lens driving unit 24, an iris driving unit 25, and a sensor driving unit 26.

  The digital zoom setting unit 22 selects (sets and cancels) the digital zoom operation mode based on the zoom information input by the operation unit 16, and when the digital zoom operation mode is selected (set), the digital zoom magnification is based on the zoom information. And the vertical imaging range of the CMOS image sensor 13 is set based on the set digital zoom magnification. The digital zoom setting unit 22 controls the digital zoom processing circuit 21 when the digital zoom operation mode is selected (set). The digital zoom processing circuit 21 enlarges the image in the zoom range imaged by the CMOS image sensor 13 according to the control command of the digital zoom setting unit 22.

  The imaging condition setting circuit 23 sets the optical zoom magnification (zoom position) of the lens 11, the iris amount of the iris 12, and the exposure time (shutter speed) of the CMOS image sensor 13 based on the operation information input from the operation unit 16. .

  The lens driving unit 24 drives the lens 11 according to the optical zoom magnification set by the imaging condition setting circuit 23. The iris driving unit 25 drives the iris 12 according to the aperture amount set by the imaging condition setting circuit 23. The sensor driving unit 26 drives the CMOS image sensor 13 with the exposure time set by the imaging condition setting circuit 23. When the digital zoom operation mode is selected by the digital zoom setting unit 22, the sensor driving unit 26 drives the CMOS image sensor 13 so as to capture the imaging range set by the digital zoom setting unit 22.

FIG. 2 is a diagram showing a configuration of the CMOS image sensor 13 shown in FIG.
As shown in FIG. 2, the CMOS image sensor 13 includes a pixel unit 31, a shutter scanning circuit 32, a readout scanning circuit 33, a driver circuit 34, and a horizontal readout circuit 35.
The pixel unit 31 includes a plurality of pixels (not shown) arranged in a matrix. Each pixel includes a photoelectric conversion unit that converts incident light of the CMOS image sensor 13 into a signal charge (pixel signal), a shutter transistor circuit that discharges the signal charge accumulated in the photoelectric conversion unit and starts exposure, and a photoelectric conversion unit. An amplifying transistor circuit for amplifying the signal charge stored in the memory, and a reading transistor circuit for reading out the signal charge amplified by the amplifying transistor circuit. The photoelectric conversion unit is made of, for example, a photodiode. The photodiode discharges the accumulated signal charge when the shutter transistor circuit is driven, initializes the pixel signal, and when the readout transistor circuit is driven, the pixel signal is read out after the accumulated signal charge is read out. Perform destructive readout to initialize the signal.

The shutter scanning circuit 32 outputs a shutter signal for driving the shutter transistor circuits of a plurality of pixels of the pixel unit 31 based on the shutter driving signal from the sensor driving unit 26 via the driver circuit 34. Are scanned in units of rows in the vertical direction of the pixels. The shutter scanning circuit 32 includes a decoder circuit that selects and scans an arbitrary row of the plurality of pixels, for example.
The readout scanning circuit 33 outputs a readout signal for driving the readout transistor circuits of the plurality of pixels of the pixel unit 31 based on the readout driving signal from the sensor driving unit 26 via the driver circuit 34. Scan line by line in the vertical direction. The readout scanning circuit 33 is composed of, for example, a decoder circuit that selects and scans an arbitrary row of the plurality of pixels.
The driver circuit 34 drives the pixel unit 31 with the shutter signal from the shutter scanning circuit 32 and the readout signal from the readout scanning circuit 33. The horizontal readout circuit 35 collectively reads out pixel signals of pixels in the same row of the pixel unit 31 selected based on the readout signal from the readout scanning circuit 33, and reads out the pixel signals for one line read out in parallel serial. Convert and output.

  In the imaging apparatus configured as described above, each unit is operated in accordance with a control command of the control circuit 19 based on the operation information of the operation unit 16. The imaging condition setting circuit 23 sets the optical zoom magnification of the lens 11, the iris amount of the iris 12 and the exposure time (shutter speed) of the CMOS image sensor 13, the lens 11 is driven by the lens driving unit 24, and the iris driving unit 25 The iris 12 is driven, and the CMOS image sensor 13 is driven by the sensor driving unit 26. The image captured by the CMOS image sensor 13 is subjected to signal processing by the signal processing circuit 14, displayed on the display unit 17, and recorded on the recording medium 18.

  When the digital zoom operation mode is selected by the digital zoom setting unit 22 based on the operation information (zoom information) of the operation unit 16, the digital zoom setting unit 22 determines the digital zoom magnification and the imaging range of the CMOS image sensor 13 according to the digital zoom magnification. The CMOS image sensor 13 is driven by the sensor driving circuit 26 so as to image the set imaging range. The image captured by the CMOS image sensor 13 is stored in the image memory 15, the zoom range is cut out by the digital zoom processing unit 21, and the enlargement process is performed.

FIG. 3 is a diagram illustrating the operation of the CMOS image sensor 13.
This operation is a so-called one-frame shutter release operation. When the exposure time is set to one frame period, the shutter driving signal is not supplied to the shutter scanning circuit 32, and the reading driving signal is supplied to the reading scanning circuit 33. The readout signal scanned by the readout scanning circuit 33 performs scanning in units of rows in the vertical direction of the pixel portion 31 in one frame period. The shutter operation is performed by a read signal.

FIG. 4 is a diagram illustrating the operation of the CMOS image sensor 13.
This operation is an operation for controlling the exposure time by driving the shutter scanning circuit 32. The exposure time is controlled in the range of 1H to 1F-1H. When the exposure time is set to be shorter than one frame period, a shutter drive signal is supplied to the shutter scanning circuit 32, and a read drive signal is supplied to the read scanning circuit 33. The shutter signal scanned by the shutter scanning circuit 32 and the readout signal scanned by the readout scanning circuit 33 scan in units of rows in the vertical direction of the pixel portion 31 in one frame period.

FIG. 5 is a diagram illustrating the operation of the CMOS image sensor 13.
In FIG. 5, A is the vertical imaging range of the pixel unit 31 set based on the digital zoom magnification (B / A) by the digital zoom setting unit 22, and B is the vertical range of the pixel unit 31 when there is no digital zoom. This is the direction imaging range. When the digital zoom operation mode is selected, the imaging range A is imaged and read from the CMOS image sensor 13. When the exposure time is set to one frame period, the shutter driving signal is not supplied to the shutter scanning circuit 32, and the reading driving signal is supplied to the reading scanning circuit 33. The readout signal scanned by the readout scanning circuit 33 performs scanning in units of rows in the vertical direction of the imaging range A in one frame period. The shutter operation is performed by a read signal.

FIG. 6 is a diagram illustrating the operation of the CMOS image sensor 13.
In FIG. 6, A is the vertical imaging range of the pixel unit 31 set based on the digital zoom magnification (B / A) by the digital zoom setting unit 22, and B is the vertical range of the pixel unit 31 when there is no digital zoom. This is the direction imaging range. When the digital zoom operation mode is selected, the imaging range A is imaged and read from the CMOS image sensor 13. Even when the digital zoom operation mode is selected, the exposure time can be controlled by driving the shutter scanning circuit 32. The exposure time is controlled in the range of 1H to 1F-1H. When the exposure time is set to be shorter than one frame period, a shutter drive signal is supplied to the shutter scanning circuit 32, and a read drive signal is supplied to the read scanning circuit 33. The shutter signal scanned by the shutter scanning circuit 32 and the readout signal scanned by the readout scanning circuit 33 scan the imaging range A in the vertical direction in units of rows in one frame period.

FIG. 7 is a diagram illustrating interference between the readout signal and the shutter signal.
As shown in FIG. 7, when the digital zoom magnification is changed, the imaging range in the vertical direction of the pixel unit 31 is changed, and the scanning speed of the shutter signal and the readout signal is changed. In such a case, the readout signal and the shutter signal that are imaged at a constant frame rate may interfere with each other. For example, in FIG. 7, as an example when the digital zoom magnification is reduced and the imaging range is increased, the shutter signal of frame (N) has the same timing in the last row of the readout signal of frame (N−1), If the exposure time is longer than this, imaging of the previous and subsequent frames will not be performed normally. On the other hand, as an example when the digital zoom magnification is increased and the imaging range is reduced, the shutter signal of the frame (N + 1) has the same timing as the readout signal of the frame (N) at the start row, and the exposure time is thereby determined. If the length is longer, the previous and next frames are not normally captured. As described above, when the digital zoom magnification is changed, the exposure time is limited.

  In the image pickup apparatus of the first embodiment, when the digital zoom magnification is changed, the control circuit 19 discards the previous and subsequent images captured by the CMOS image sensor 13 so that the previous image is used instead of the discarded image. Use an image.

As described above, according to the first embodiment, the CMOS image sensor 13 captures an imaging range set by the digital zoom setting unit 22 based on the digital zoom magnification.
Therefore, an image in the imaging range corresponding to the digital zoom magnification can be read from the solid-state imaging device, so that the capacity of the image memory 15 for storing the read image can be reduced, thereby reducing the cost of the imaging device. it can.
Also, since the images before and after the digital zoom magnification is changed are discarded so as not to be used, images that may not be normally captured due to interference between the readout signal of the subsequent image and the shutter signal of the previous image are excluded, It is possible to prevent image disturbance.

  In the first embodiment, when the digital zoom magnification is changed, the control circuit 19 discards the images before and after the image captured by the CMOS image sensor 13 so as not to be used. Therefore, even when there is no interference between the readout signal and the shutter signal as shown in FIG. 7, the images before and after that are discarded. On the other hand, the image pickup apparatus according to the second embodiment does not discard the image when there is no interference between the readout signal and the shutter signal. In the second embodiment, parts different from the first embodiment will be described.

  When the digital zoom magnification is changed, the digital zoom setting unit 22 of the imaging apparatus according to the second embodiment calculates the maximum exposure time in which there is no interference between the readout signal and the shutter signal based on the digital zoom magnification before and after the change. The exposure time is compared with the exposure time set by the imaging condition setting unit 23. When the comparison information of the digital zoom setting unit 22 exceeds the maximum exposure time calculated by the imaging condition setting unit 23, the control circuit 19 before and after the digital zoom imaged by the CMOS image sensor 13 is changed. The previous image is discarded so that the previous image is used instead of the discarded image.

The maximum exposure time is expressed by the following formula, for example.
Maximum exposure time = 1 + MAX (Z (N−1), Z (N)) / MIN (Z (N−1), Z (N)) × F / 2
Where Z (N−1): digital zoom magnification of frame (N−1),
Z (N): Digital zoom magnification of frame (N),
F: One frame period.

FIG. 8 is a diagram illustrating an example of the maximum exposure time when the digital zoom magnification is changed.
As understood from FIG. 8, when the digital zoom magnification is not changed, the maximum exposure time is one frame period. When the digital zoom magnification is changed, the maximum exposure time is shorter than one frame period. The maximum exposure time when the magnification is changed to M times coincides with the maximum exposure time when the magnification is changed to 1 / M times. The digital zoom setting unit 22 may store the maximum exposure time shown in FIG. 8 instead of calculating the maximum exposure time by the above formula, and perform the calculation by table lookup.

  As described above, according to the second embodiment, an image in which the readout signal and the shutter signal do not interfere with each other is not discarded, and only an image in which the readout signal and the shutter signal interfere with each other is discarded. Can be obtained.

In the third embodiment, parts different from the first and second embodiments will be described.
As in the second embodiment, the digital zoom setting unit 22 of the imaging apparatus according to the third embodiment calculates the maximum exposure time when the digital zoom magnification is changed. Then, the imaging condition setting circuit 23 sets the exposure time so as not to exceed the maximum exposure time calculated by the digital zoom setting unit 22.
As described above, according to the third embodiment, even when the zoom magnification changes, the CMOS image sensor 13 can capture a normal image without any disturbance, and the digital zoom magnification is changed as in the first and second embodiments. There is no need to discard the previous and next images.

In the fourth embodiment, parts different from the first to third embodiments will be described.
When the digital zoom operation mode is selected by the digital zoom setting unit 22, the imaging condition setting circuit 23 according to the fourth embodiment sets the maximum exposure time to ½ of one frame period so as not to exceed the set maximum exposure time. Set the exposure time to. The digital zoom setting unit 22 limits the zoom magnification change rate based on the maximum exposure time set by the imaging condition setting circuit 23.
As shown in FIG. 8, when the zoom magnification is changed from 1 to 16 times and when the zoom magnification is changed from 16 to 1 time, the maximum exposure time is 0.53. Therefore, if the maximum exposure time is 0.5, there is no interference between the readout signal of frame (N-1) and the shutter signal of frame (N) as long as the zoom magnification changes within this range.
As described above, according to the fourth embodiment, even when the zoom magnification changes, the CMOS image sensor 13 can capture a normal image without disturbance, and the digital zoom magnification is changed as in the first and second embodiments. There is no need to discard the previous and next images.

FIG. 9 is a diagram illustrating a configuration of a CMOS image sensor of the imaging apparatus according to the fifth embodiment.
As shown in FIG. 9, the CMOS image sensor includes a pixel unit 31, a shutter shift register 42, a readout shift register 43, a driver circuit 44, and a horizontal readout circuit 35.
The same components as those of the CMOS image sensor shown in FIG. 2 are denoted by the same reference numerals, and description thereof is omitted.

  The shutter shift register 42 outputs a shutter signal for driving shutter transistor circuits of a plurality of pixels of the pixel unit 31 based on a shutter drive signal (shift register input pattern signal and shift clock signal) from the sensor drive unit 26. Through the driver circuit 34, scanning is sequentially performed in units of rows in the vertical direction of the plurality of pixels of the pixel unit 31. The read shift register 43 outputs a read signal for driving a transistor circuit for reading a plurality of pixels in the pixel unit 31 based on a read drive signal (shift register input pattern signal and shift clock signal) from the sensor drive unit 26. The driver circuit 34 sequentially scans the plurality of pixels in the vertical direction in units of rows. The driver circuit 44 drives the pixel unit 31 based on the shutter signal (bit position information) from the shutter scanning circuit 42 and the readout signal (bit position information) from the readout scanning circuit 33.

  The CMOS image sensor of the fifth embodiment performs the same operation as the CMOS image sensor of the first embodiment shown in FIGS. Further, the CMOS image sensor according to the fifth embodiment has an interference between the read signal and the shutter signal similarly to the operation of the CMOS image sensor according to the first embodiment shown in FIG. For this reason, the imaging apparatus according to the fifth embodiment performs imaging under the condition that there is no interference between the readout signal and the shutter signal as in the imaging apparatuses according to the third and fourth embodiments, or reads out like the imaging apparatus according to the second embodiment. When interference between the signal and the shutter signal occurs, the corresponding image is discarded. When the digital zoom magnification is changed as in the image pickup apparatus of the first embodiment, the corresponding image is discarded.

FIG. 10 is a diagram illustrating a problem of interference between shutter signals.
In the CMOS image sensor of the fifth embodiment, the shutter signal is scanned by the shutter shift register 42, and the read signal is scanned by the read shift register 43. When the digital zoom operation mode is selected, the shutter signal and the readout signal are shifted at high speed from the first row of the pixel unit 31 to the start row of the imaging range, and from the end row of the imaging range to the last row of the pixel unit 31 at high speed. Shifted. For this reason, when the exposure time is changed long, an abnormality occurs in the image of the previous frame (N-1).

As shown in FIG. 10A, when the exposure time is constant without changing, the shutter signal of frame (N-1) and the shutter signal of frame (N) are the same as the respective readout signals. Does not interfere. Further, as shown in FIG. 10C, even when the exposure time is changed to be small, the shutter signal of the frame (N-1) and the shutter signal of the frame (N) do not interfere with each other.
On the other hand, as shown in FIG. 10B, when the exposure time is changed to a small value, the shutter signal of frame (N) interferes with the shutter signal of frame (N−1). That is, when the shutter signal of the frame (N) is shifted at high speed from the first row of the pixel unit 31 to the start row of the imaging range, the shutter signal of the frame (N-1) is similarly shifted at high speed, so that the frame An abnormality occurs in (N-1).

For this reason, when the exposure time is changed for a long time during digital zooming, the control circuit 19 of the imaging apparatus according to the fifth embodiment discards the image before the change and uses the previous image instead of the discarded image. .
As described above, according to the fifth embodiment, when the exposure time is changed for a long time during digital zooming, images that are not normally captured are excluded. Accordingly, it is possible to prevent the image from being disturbed.

FIG. 11 is a diagram illustrating a configuration of a CMOS image sensor of the imaging apparatus according to the sixth embodiment.
As shown in FIG. 11, the CMOS image sensor of the sixth embodiment includes a shutter shift register 42 of the CMOS image sensor of the fifth embodiment shown in FIG. 10, a first shutter shift register 51 and a second shutter shift register 52. It has been replaced with.
The first and second shutter shift registers 51 and 52 are divided substantially at the center of the pixel unit 31 and are driven by independent shutter drive signals.
In the CMOS image sensor of the sixth embodiment, the first and second shutter shift registers 51 and 52 are driven by independent shutter drive signals, so that the first shutter shift register 51 generates a shutter signal of the frame (N). Even when shifted at high speed, the shutter signal of the frame (N−1) can be normally shifted by the second shutter shift register 52.
As described above, according to the sixth embodiment, since a normal imaging operation can be performed even when the exposure time is set to be long, when the exposure time is changed to be long as in the fifth embodiment, the pre-change operation is performed. There is no need to discard the image.

FIG. 12 is a diagram illustrating a configuration of a CMOS image sensor of the imaging apparatus according to the seventh embodiment.
As shown in FIG. 12, the CMOS image sensor of the seventh embodiment is different from the CMOS image sensor of the fifth embodiment shown in FIG. 10 in that the shutter shift register 42, the first shutter shift register 61, and the second shutter shift register. 62, a drive signal switching circuit 63 and a shutter signal switching circuit 64.
The drive signal switching circuit 63 receives shutter drive signals (shift register input pattern signal and shift clock signal). The drive signal switching circuit 63 switches and outputs the input shutter drive signal to the first and second shutter shift registers 61 and 62 alternately in the imaging order. As a result, the shutter signals are alternately output in the order of imaging by the first and second shutter shift registers 61 and 62. The shutter signal switching circuit 64 alternately switches and inputs and outputs the shutter signals output alternately by the first and second shutter shift registers 61 and 62 in the imaging order.

Even in the CMOS image sensor of the seventh embodiment, even when the shutter signal of the frame (N) is shifted at a high speed by the first shutter shift register 51, the shutter signal of the frame (N-1) is output by the second shutter shift register 52. It can be shifted normally.
As described above, according to the seventh embodiment, even when the exposure time is set to be long, a normal imaging operation can be performed. Therefore, when the exposure time is changed to be long as in the fifth embodiment, the change before the change is performed. There is no need to discard the image.

  DESCRIPTION OF SYMBOLS 11 ... Lens, 12 ... Iris, 13 ... CMOS image sensor, 14 ... Signal processing circuit, 15 ... Image memory, 16 ... Operation part, 17 ... Display part, 18 ... Control circuit, 21 ... ... Digital zoom processing unit, 22 ... Digital zoom setting unit, 23 ... Imaging condition setting circuit 23, 24 ... Lens driving circuit, 25 ... Iris driving circuit, 26 ... Sensor driving circuit

Claims (15)

The exposure time of an XY address type solid-state imaging device in which the exposure time is controlled by a shutter signal for starting exposure and a readout signal for ending exposure that scan a plurality of pixels arranged in a matrix in the vertical direction. An exposure time setting step to be set;
A digital zoom step of setting a zoom magnification when a digital zoom operation mode for enlarging an image captured by the solid-state image sensor is selected, and enlarging an image captured by the solid-state image sensor at the set zoom magnification. An imaging method,
An imaging range setting step for setting an imaging range in the vertical direction of the solid-state imaging device according to the zoom magnification set in the digital zoom step;
A drive signal for scanning the shutter signal and the readout signal is output so that exposure of the imaging range set in the imaging range setting step is performed with the exposure time set in the exposure time setting step, and the solid-state imaging device is A driving step for driving,
In the exposure time setting step, when the zoom magnification is changed in the digital zoom step, a shutter signal that scans the imaging range according to the changed zoom magnification scans the imaging range according to the zoom magnification before the change. A calculation step of calculating the maximum exposure time of the solid-state imaging device based on the zoom magnification before and after the change so as not to interfere with the readout signal, and the maximum exposure time calculated in the calculation step is not exceeded Set the exposure time of the solid-state image sensor ,
An imaging method. A plurality of pixels arranged in a matrix, a shutter scanning circuit for discharging accumulated signal charges and starting a shutter signal for starting exposure in a row unit in the vertical direction of the plurality of pixels, and the exposure is completed and accumulated. A readout scanning circuit that scans a readout signal for reading out the signal charges in units of rows in the vertical direction of the plurality of pixels, and an exposure time is controlled by the shutter signal and the readout signal. A solid-state image sensor;
Exposure time setting means for setting an exposure time of the solid-state imaging device;
Digital zoom means for setting a zoom magnification and enlarging an image captured by the solid-state image sensor at the set zoom magnification when a digital zoom operation mode for enlarging an image captured by the solid-state image sensor is selected. An imaging device comprising:
An imaging range setting unit that sets an imaging range in a vertical direction of the solid-state imaging device according to a zoom magnification set by the digital zoom unit;
A drive signal for scanning the shutter signal and the readout signal is output so that exposure of the imaging range set by the imaging range setting unit is performed with the exposure time set by the exposure time setting unit, and the solid-state imaging device is Driving means for driving,
When the zoom magnification is changed by the digital zoom means, the exposure time setting means scans the imaging range according to the zoom magnification before the change by the shutter signal that scans the imaging range according to the changed zoom magnification. Computation means for computing the maximum exposure time of the solid-state imaging device based on the zoom magnification before and after the change so as not to interfere with the readout signal, so as not to exceed the maximum exposure time computed by the computation means Setting an exposure time of the solid-state imaging device ;
Imaging device. The shutter scanning circuit that Do from any row of selectable decoders of said plurality of pixels
Imaging device 請 Motomeko 2 wherein. The shutter scanning circuit that Do from the shift register for sequentially scanning the plurality of pixels in the vertical direction line by line
Imaging device 請 Motomeko 2 wherein. When the digital zoom operation mode is selected and the exposure time is increased by the exposure time setting means, the image taken by the solid-state image sensor is discarded so as not to use the image before the exposure time is increased. with disposal means to
請 Motomeko 4 imaging device according. The shutter scanning circuit includes first and second shift registers that independently scan the first and second ranges obtained by dividing the vertical scanning range of the plurality of pixels at substantially the center thereof. Ru
Imaging device 請 Motomeko 2 wherein. The shutter scanning circuit alternately includes first and second shift registers to which the shutter driving signals are alternately input in the order of imaging, and shutter signals scanned by the first and second shift registers in the order of the imaging. that having a a switching circuit for outputting a switching said plurality of pixels
Imaging device 請 Motomeko 2 wherein. A plurality of pixels arranged in a matrix are captured by an XY address type solid-state imaging device whose exposure time is controlled by a shutter signal for starting exposure and a readout signal for ending exposure that scans in the vertical direction. An imaging method including a digital zoom step of setting a zoom magnification when a digital zoom operation mode for enlarging an image is selected and enlarging an image captured by the solid-state imaging device at the set zoom magnification,
When the digital zoom operation mode is selected, the maximum exposure time of the solid-state imaging device is set to a predetermined time shorter than the vertical scanning period of the readout signal, and the solid-state imaging device is set so as not to exceed the set maximum exposure time. An exposure time setting step for setting the exposure time;
An imaging range setting step for setting an imaging range in the vertical direction of the solid-state imaging device according to the zoom magnification set in the digital zoom step;
A drive signal for scanning the shutter signal and the readout signal is output so that exposure of the imaging range set in the imaging range setting step is performed with the exposure time set in the exposure time setting step, and the solid-state imaging device is A driving step for driving,
In the digital zoom step, when the zoom magnification is changed, the shutter signal that scans the imaging range according to the zoom magnification after the change does not interfere with the readout signal that scans the imaging range according to the zoom magnification before the change. Includes a maximum change rate setting step for setting a maximum change rate of the zoom magnification based on the maximum exposure time set in the exposure time setting step, and does not exceed the maximum change rate set in the maximum change rate setting step. To change the zoom magnification ,
An imaging method. A plurality of pixels arranged in a matrix, a shutter scanning circuit for discharging accumulated signal charges and starting a shutter signal for starting exposure in a row unit in the vertical direction of the plurality of pixels, and the exposure is completed and accumulated. A readout scanning circuit that scans a readout signal for reading out the signal charges in units of rows in the vertical direction of the plurality of pixels, and an exposure time is controlled by the shutter signal and the readout signal. A solid-state image sensor;
Digital zoom means for setting a zoom magnification and enlarging an image captured by the solid-state image sensor at the set zoom magnification when a digital zoom operation mode for enlarging an image captured by the solid-state image sensor is selected. An imaging device comprising:
When the digital zoom operation mode for operating the digital zoom means is selected, the maximum exposure time of the solid-state imaging device is set to a predetermined time shorter than the vertical scanning period of the readout signal so as not to exceed the set maximum exposure time. Exposure time setting means for setting an exposure time of the solid-state imaging device;
An imaging range setting unit that sets an imaging range in a vertical direction of the solid-state imaging device according to a zoom magnification set by the digital zoom unit;
Shutter driving signal for scanning the shutter signal by the shutter scanning circuit and the scanning circuit for readout so that the exposure of the imaging range set by the imaging range setting means is performed with the exposure time set by the exposure time setting means And a driving means for driving the solid-state imaging device, outputting a driving signal for reading that scans the reading signal.
When the zoom magnification is changed, the digital zoom means prevents a shutter signal that scans the imaging range according to the changed zoom magnification from interfering with a read signal that scans the imaging range according to the zoom magnification before the change. The maximum change rate setting means for setting the maximum change rate of the zoom magnification based on the maximum exposure time set by the exposure time setting means, and exceeds the maximum change rate set by the maximum change rate setting means. changing the zoom magnification so as not,
Imaging device. The exposure time setting means to set the maximum exposure time to 1/2 of the vertical scanning period of the read signal
Imaging device 請 Motomeko 9 wherein. The shutter scanning circuit that Do from any row of selectable decoders of said plurality of pixels
Imaging device 請 Motomeko 9 wherein. The shutter scanning circuit includes a shift register that sequentially scans the plurality of pixels in units of rows in the vertical direction.
Imaging device 請 Motomeko 9 wherein. When the digital zoom operation mode is selected and the exposure time is increased by the exposure time setting means, the image taken by the solid-state image sensor is discarded so as not to use the image before the exposure time is increased. with disposal means to
請 Motomeko 12 imaging device according. The shutter scanning circuit includes first and second shift registers that independently scan the first and second ranges obtained by dividing the vertical scanning range of the plurality of pixels at substantially the center thereof. Ru
Imaging device 請 Motomeko 9 wherein. The shutter scanning circuit alternately includes first and second shift registers to which the shutter driving signals are alternately input in the order of imaging, and shutter signals scanned by the first and second shift registers in the order of the imaging. that having a a switching circuit for outputting a switching said plurality of pixels
Imaging device 請 Motomeko 9 wherein.

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