WO2005018224A1

WO2005018224A1 - Zoom imager

Info

Publication number: WO2005018224A1
Application number: PCT/JP2003/010310
Authority: WO
Inventors: Shuhei Kanda; Keiji Izumi
Original assignee: Kyoshin Technosonic Co., Ltd.
Priority date: 2003-08-13
Filing date: 2003-08-13
Publication date: 2005-02-24
Also published as: AU2003257829A1

Abstract

An image sensing device (12) having pixels more than necessary for a camera signal output is combined with an optical lens (11) whose magnification is changeable. The pixel signals obtained by the image sensing device (12) are subjected to electronic zooming by a zoom processing means (14). Zoom processing is conducted by combining the electronic zooming and magnification change in the optical lens (11).

Description

TECHNICAL FIELD The present invention relates to a zoom photographing apparatus suitable for use in a digital camera such as an electronic still camera, a camera-equipped mobile phone, and a camera-integrated video recording / reproducing apparatus. 2. Description of the Related Art Conventionally, as a high-magnification zoom photographing device used in digital cameras such as electronic still cameras and camera-type video recording / reproducing devices, a method of gradually changing the angle of view using an optical zoom lens, and an image pickup device There is an electronic zoom method in which the angle of view is gradually reduced stepwise from the image signal obtained from the image signal, and the image signal is reduced to a predetermined number of pixels, and the number of pixels is adjusted, and these are used alone or in combination. Photographing equipment is used.

In a zoom photographing apparatus using this optical zoom lens, the optical zoom lens is mechanically moved back and forth along the optical axis to continuously adjust the zoom magnification. Not only must the moving distance be increased, but also the mechanism must be able to move with high precision mechanically, which not only complicates the structure, but also makes it difficult to reduce the size and weight of the electronic still camera. It is disadvantageous to apply to such as.

On the other hand, in the electronic zoom method, the angle of view is gradually reduced from the image signal obtained from the image sensor, and the image signal is reduced by increasing the image signal to a predetermined number of pixels.

—The system is performing a system operation. For example, as shown in FIG. 10, when the required resolution of the camera is set to the resolution of the image sensor having the number of pixels of 640 × 480, as shown in FIG. The output of all of the 40 × 480 pixels is output from the camera as an image signal as it is. Therefore, for example, in the case of realizing a 2 × electronic zoom, one of the set of pixels shown in the pixel portion of 320 × 240, out of the image sensor having 64 × 480 pixels, is used. The BG GR signal is written into the memory space of 640x480 as shown in Fig. 11, for example, by increasing it to four sets of signals as shown by the diagonal lines rising to the right in the figure, and similarly writing to the entire area. By performing the operation over the entire range, an image signal of 640 × 480 is created. Also, in order to realize a 4 × zoom, one set of BG GR is set from the signal of the pixel portion of 160 × 120 pixels of the image sensor, and one set indicated by the diagonally downward-sloping line in the figure is a set of BG GR. By increasing the number of signals for 16 sets and writing the same over the entire area, an image signal of 640 × 480 is created. Further, to realize a multiplication factor that is not an integral multiple, it can be realized by increasing the original set of BG GRs to a set of squares of the zoom magnification, including interpolation processing.

In any case, the higher the magnification, the more the number of pixels will be used, from the pixels possessed by the image sensor to the pixel signals in the range of narrowing the angle of view, and the resolution will increase as the magnification increases. Will be deteriorated.

A compact and lightweight video camera device has been announced by simplifying the configuration of such an optical zoom lens and combining it with an electronic zoom. This video camera device achieves a total zoom ratio of 6 to 8 times by combining a small and lightweight zoom lens with a small zoom ratio of 2 to 3 times and an electronic zoom. Even in this case, at least two or more lens groups must be moved on the optical axis, so the focal length can be switched by moving only one lens group instead of the optical zoom lens. It is composed of a two-focal distance lens, an image sensor, a preamplifier circuit, and a video scaling operation circuit, and is provided with a zoom function distribution unit and an electronic zoom magnification operation unit. As a result, a video camera device with an electronic zoom function, in which the switching of the two focal length lenses and the magnification of the electronic zoom are automatically processed and the change of the optically equivalent total focal length is smoothed, is disclosed in Japanese Patent Application Laid-Open Publication No. It is disclosed in Japanese Patent Application Publication No. 156445.

In a video camera, a multifocal imaging lens capable of switching the focal length and changing the optical magnification discontinuously is provided, and an image is enlarged for a video signal obtained by processing an imaging signal from an imaging device. Electronic zoom means for processing and responding to zoom operation Then, the optical magnification of the multifocal imaging lens is switched and the electronic zoom magnification in the electronic zoom means is controlled so as to interpolate a magnification other than the optical magnification switched by the multifocal imaging lens, thereby continuously changing the zoom magnification. An apparatus having a zoom control means is disclosed in Japanese Patent Application Laid-Open No. 8-18842.

In this video camera, the optical magnification of the multifocal lens is switched in accordance with the zoom operation by the zoom lever, and the electronic zoom circuit in the electronic zoom circuit is configured to interpolate a magnification other than the optical magnification switched by the multifocal lens. Is controlled by a microcomputer. For example, if the electronic zoom magnification is 3 times and the obtained zoom magnification is equal to 3 times the optical magnification next to 1 time of the multifocal lens, the microcomputer The optical magnification of the multifocal lens is switched to 3 times, and the electronic zoom magnification in the electronic zoom circuit is returned to 1x by the microcomputer.

In this way, the zoom lens is used by controlling the electronic zoom magnification of the electronic zoom circuit so as to interpolate a magnification other than the optical magnification switched by the multifocal lens, and by continuously changing the obtained zoom magnification. The zoom magnification is continuously changed as in the case where a zoom lens is used. In addition, because a multifocal lens is used, the structure of the lens system is simplified, adjustment for correcting optical variations is simplified, and the cost, size, and weight are reduced.

However, in each of the video cameras disclosed in these patent publications, the number of pixels required as an image sensor at 1 × is the same as the number of pixels obtained as a camera output. . For this reason, when the electronic zoom operation is performed using this image sensor, the image signal obtained from this image sensor is stepwise reduced in view angle to reduce the image signal to a predetermined magnification. Since the digital zoom method that increases the number of pixels to be used is adopted, the camera output signal obtained is a signal equivalent to the pixel with a significantly reduced number of pixels, and the resolution is greatly reduced. There is a problem that it will.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a zoom photographing apparatus that is small and lightweight and that can obtain high-quality images without deteriorating resolution. . DISCLOSURE OF THE INVENTION A zoom photographing apparatus according to the present invention comprises: an optical lens whose magnification is switched stepwise to a plurality of fixed magnifications; and an image sensor which converts an optical image photographed and formed by the optical lens into an image signal. Read-out control means for reading out image signals in a predetermined range of the image sensor in a predetermined order; electronic zoom processing of the image signals read out by the read-out control means, and camera signals of a predetermined number of pixels And a magnification switching means for switching the magnification of the optical lens by the zoom processing means. The number of pixels of the image sensor is made larger than the number of pixels of the camera signal output from the zoom processing means. It is set to increase.

Further, in the zoom photographing apparatus of the present invention, the magnification of both the optical lens and the electronic zoom is switched, and the switching is performed so that the total magnification before and after the switching becomes constant.

Further, in the zoom imaging device of the present invention, 1 the magnification of the optical lens, a magnification, a ^2-fold, in the case of setting to be switched to a ^3-fold ... a ⁿ times, the electronic zoom magnification l set up more ~a times, and is characterized in that setting the number of pixels of the image pickup element so that more than ^twice the predetermined number of pixels of a camera signal outputted from the electronic zoom.

Still further, in the zoom photographing device of the present invention, the zoom processing unit increases the magnification of the electronic zoom, and when the magnification reaches the second magnification a set in the optical lens, the zoom processing unit increases the current magnification. The magnification of the optical lens is switched so that the magnification becomes a times, and the electronic zoom magnification is switched to 1 times. Further, in the zoom photographing device of the present invention, the zoom processing means reduces the magnification of the electronic zoom and, when the magnification reaches 1 ×, the second stage set in the optical lens with respect to the current magnification. The magnification of the optical lens is switched so that the magnification is divided by the magnification a, and the electronic zoom magnification is switched to a.

Further, in the zoom photographing apparatus according to the present invention, it is preferable that the optical zoom magnifications at the plurality of magnification switching points are set to different values in the wide-angle and telephoto operation directions, respectively. It is a feature.

Further, in the zoom photographing apparatus of the present invention, it is preferable that the image signal obtained by the image pickup device is thinned out from an image signal in a range in which the angle of view is widened by the electronic zoom and converted into a predetermined number of pixels. It is a feature.

Further, the zoom photographing apparatus of the present invention is characterized in that a partial integration process is performed on an image signal in a range in which the angle of view is widened by the electronic zoom to convert the image signal into a predetermined number of pixels.

The zoom photographing apparatus according to the present invention is characterized in that the switching timing of the optical lens is switched at a timing other than during the exposure of the imaging device.

With this configuration, an inexpensive zoom photographing apparatus that has a simple structure and is suitable for a small and light-weight lens can be obtained by using an optical lens with a small resolution deterioration and a reduced number of magnification switching steps. Can be. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram showing an embodiment of a zoom photographing apparatus according to the present invention. FIG. 2 is an explanatory diagram for explaining a used pixel state at the time of electronic zoom of an image pickup device used in the zoom photographing apparatus.

FIG. 3 is an explanatory diagram for explaining a pixel arrangement state of the image sensor.

FIG. 4 is an explanatory diagram for explaining a used pixel state of the image sensor during electronic zoom.

FIG. 5 is an explanatory view for explaining a pixel arrangement state in the same case. FIG. 6 is a simplified explanatory diagram for explaining in detail the pixel arrangement state in that case.

FIG. 7 is an explanatory diagram for explaining a zoom operation of the zoom photographing apparatus according to the present invention. FIG. 8 is an explanatory diagram for explaining a pixel arrangement state in the zoom state. FIG. 9 is an explanatory diagram for explaining another zoom operation of the zoom photographing apparatus according to the present invention. FIG. 10 is an explanatory diagram for explaining a used pixel state of an image sensor in an electronic zoom in a conventional zoom photographing apparatus.

FIG. 11 is an explanatory diagram for explaining a pixel array state of the image sensor. DETAILED DESCRIPTION OF THE INVENTION Embodiments of a zoom photographing apparatus according to the present invention will be described in detail with reference to the drawings.

First, in the zoom photographing apparatus according to the present invention, the electronic zoom magnification in the zoom photographing apparatus is changed to, for example, 1 to 2 times, and the required resolution of the camera signal is set to, for example, 640 × 480 pixels. The number of pixels of the image pickup device 12 to be used is set to 1280 × 960 pixels having pixels whose square is twice the maximum magnification of the electronic zoom magnification which is larger than the required number of pixels.

Further, as shown in FIG. 1, the zoom photographing apparatus according to the present invention has an optical lens 11 capable of switching the magnification between 1 × and 2 ×, and an image photographed by the optical lens 11. Is imaged on an imaging surface of an imaging element 12 composed of a CMOS type CMOS sensor having a 1280 × 960 pixel photodiode having 1280 × 960 pixels, for example. The image formed on the imaging surface of the imaging device 12 is photoelectrically converted by each photodiode, and the converted image signal is accumulated in the photodiode, and the signal of each pixel in the imaging device 12 is converted into a signal. By controlling the switch means for designating and taking out the position by the reading control means 13, the image signals of the photodiodes at the designated position are taken out in order, and the image is digitized.

The image signal read in this way is supplied to the zoom processing means 14 including a microcomputer, a memory, a DSP, and the like. A zoom switch 15 for designating the direction of telephoto (TELE) and wide angle (WIDE) and for instructing a change in zoom magnification is connected to the zoom processing means 14. The zoom processing means 14 performs the zoom operation instructed by the control direction of ££ / 10 £ from the zoom switch 15 and the control signal of the zoom magnification. A control signal for reading out a signal from a photodiode at a specified position of the image sensor 12 in a specified order is supplied to the readout control means 13, and the obtained image signal is subjected to electronic zoom operation processing and an optical lens is processed. A control signal for switching the angle of view of 11 is also supplied to the magnification switching means 16.

The drive signal from the magnification switching means 16 drives a switching drive mechanism constituted by a solenoid or the like in the optical lens 11 to increase the angle of view of the optical lens 11 to 1 or 2 times. Instantaneously.

The electronic zoom operation processing means in the zoom processing means 14 performs interpolation processing as needed on the image signal obtained from the image pickup device 12 and performs processing for thinning out the signal of 640 × 480 pixels, which is obtained here. The BGGR signal of 640 x 480 pixels is transmitted to the camera signal processing means 17, and the camera signal processing means 17 performs signal processing and output timing control, and outputs a 640x480 YUV or RGB camera signal. ing.

Therefore, assuming now that the angle of view of the optical lens 11 is set to 1 and the electronic zoom is also set to 1x, the maximum angle of view of this zoom photographing apparatus is 1 when the angle of view of the optical lens 11 is 1 As shown in Fig. 2, 1280x960, which is the maximum imaging range of the image sensor 12, which is (640x2) X (480x2), corresponds to the state in which an image in that range is being taken, as shown in Fig. 2. ing. Even in such a case, the camera signal output from the camera signal processing unit 17 is 640 × 480 pixels, and as shown in FIG. A control signal is supplied so as to thin out and extract signals of 320 × 240 pairs of pixels (shown by diagonal lines) with one set of BGGRs corresponding to a quarter of the entire pixels from among all the pixels of the image sensor 12. I have. For this reason, the image signal taken out of the image sensor 12 and output to the zoom processing means 14 is a signal of 640 × 480 pixels, and this image signal is supplied from the zoom processing means 14 to the camera signal processing means 17 in a predetermined order. As a result, the required camera signal of 640 X 480 pixels is obtained.

Therefore, the necessary arithmetic processing and output timing control are performed by the camera signal processing means 17, and the camera signal processing means 17 thins out a predetermined amount of pixels from all the pixels within the 1280 × 960 pixel field of view. 640x480 pixels It is output as the corresponding YUV or RGB video signal.

When the zoom switch 15 is slightly operated in the TELE direction at the position of the maximum angle of view, the operation of the zoom switch 15 is sensed by the zoom processing means 14, and a control signal corresponding to this operation is supplied to the read control means 13. As a result, as shown in FIG. 4, for example, a signal in the range of 1272 × 952 is extracted from the image sensor 12 and supplied to the zoom processing means 14. Also in this case, since the camera signal output from the camera signal processing means 17 is fixed at 640x480, in order to extract the signal of this 640x480 pixel, the range of 1272x952 shown by the dotted line in FIG. It is necessary to extract the image signals of each set of BGGR corresponding to the position indicated by the broken line where 320X240 sets with one set of BGGR are virtually arranged. For this purpose, the read control means 13 is controlled from the zoom processing means 14 to read out the output signals of the pixels straddling the shifted virtual position from the image pickup device 12 to obtain the required image signal. Then, in the zoom processing means 14, an image signal corresponding to the overlapping of the virtual range from the read pixel is added for each color from the image signal of each pixel at a ratio according to the overlap, and is extracted as a color signal at that position. Perform arithmetic processing. That is, if the position is set with reference to a pixel having one set of BGGR of each of the four corners in the range of 1272X952, the four corners indicated by I in FIG. 5 become as shown in FIG. 6 (a). Since they are completely matched with the pixels of BGGR, the B, G, and R image signals can be expressed as follows.

The numbers in parentheses indicate the pixels at the positions indicated by (row number, column number) shown in FIG. B (5, 5), G (5, 6), etc. indicate the magnitude of the signal obtained from the pixel for each color at that position.

B = B (5, 5)

2 G = G (5, 6) + G (6, 5)

R = R (6, 6)

Since the image has been enlarged to 1280/1272 times by the electronic zoom operation, the area of the image pickup surface of the image pickup device 12 has been reduced to a range of 1272x952, and the next value of the next BGGR to be read next is in the row direction. In each of the four corners, a virtual BGGR set separated by about one set of BGGRs in the column direction In this case, the image signal at the position of the virtual BGGR is obtained from the combination of the pixels straddling the virtual BGGR at a slightly shifted position without matching the pixels at each BGGR. These sets of BGGRs consist of 320 x 240 pixels when the output is 640 x 480 pixels, and in the case of 1x electronic zoom that outputs a range of 1280 x 960 pixels, from the set of 640 x 480 pixels in both row and column directions One set is thinned out to get 1/4 320X240. However, when trying to obtain 320 × 240 pixels from the range of 1272 × 952 pixels, the gaps are narrowed in the row direction and the column direction, respectively, and the number of gaps in the row direction is as follows.

The number of pixels equivalent to the gap in the row direction 2 1272-(320 x 2) = 632 If this is viewed as a gap in the row direction, the length of one pixel corresponding to the gap is as follows Become.

Gap corresponding to the gap in the row direction Length of one pixel = 632/640 = 0.9875 Since the gap is continuous by two,

The length of two pixels equivalent to the gap in the row direction = 2 x 0.99875 = 1.975 Similarly, the gap in the column direction is

The number of pixels corresponding to the gap in the column direction = 952-(240 x 2) = 472. Therefore,

The length of one pixel equivalent to the gap in the column direction = 472/480 = 0.9833 Since the gap is continuous for two pixels,

The length of two pixels corresponding to the gap in the column direction = 2 × 0.9833 = 1.9667.

Therefore, the virtual BGGR set shown in II in Fig. 5 separated by one set of BGGR from the four corners shown in Fig. 5 in the column direction as shown in Fig. 6 (b) A shift occurs only in the column direction without shifting in the direction.

The image signals obtained as B, G, and R based on this shift can be expressed as follows.

B = B (9, 5)

2G = 0.333xG (8, 5)

+ 0.96667 XG (10, 5) + G (9, 6)

R = 0. 0333 XR (8, 6)

+ 0.96667 xR (10, 6)

That is, for the image signal of B, the image signal is read from all the pixels of B (9, 5), but for the image signal of G, 0 of G (8, 5) in G (9, 6) . 0333 minutes and 0.967 minutes of G (10,5) are added to form an image signal that has been processed.

Similarly, the R image signal is an image signal obtained by adding 0.0333 minutes of R (8, 6) and 0.9667 minutes of R (10, 6) to an arithmetic operation. On the other hand, as shown in Fig. 6 (c), in the virtual BGGR set shown in Fig. 5 with one set of BGGRs separated from the position of II in the row direction, as shown in Fig. 6 (c), Misalignment will occur.

That is, the image signal of B is

B = B (9, 9)

The image signal of G is

2 G = 0.025 xG (9, 8)

+ 0.975 XG (9, 10)

+ 0.0333 XG (8, 9)

+ 0.96667 XG (10, 9)

The image signal obtained from each of the four G pixels is subjected to arithmetic processing.

Similarly, the image signal of:

R = 0.0333 x 0.025 xR (8, 8)

+ 0.9667 x 0.025 xR (10, 8)

+ 0.0333 x 0.975 xR (8, 10)

+ 0.96667 x 0.95 xR (10, 10)

The image signal obtained from each of the four R pixels is subjected to arithmetic processing.

By performing these correction calculation processes for each combination of pixels at each predetermined virtual position, Thus, image signals at different positions in the BGGR set are obtained.

The signal of the 640 × 480 pixels obtained by performing the arithmetic operation of the correction in the zoom processing means 14 as described above is input to the camera signal processing means 17 in a predetermined order, and By performing predetermined arithmetic processing and output timing control by the signal processing means 17, predetermined pixels are thinned out from pixels in the range of the angle of view of 127 2 x 952 pixels, and 6400 x It is output as a video signal of YUV or: RGB corresponding to 480 pixels.

Such an operation is performed by gradually narrowing the angle of view according to the zoom-up operation of the zoom switch 15 and performing the same processing, thereby gradually reducing the angle of view of the signal taken out from the zoom processing means 14. The range is narrowed, and control is performed to the point where 64 × 480 pixels are extracted as shown by the hatched portions in FIG. 2, so that a video signal of a double electronic zoom image is finally obtained. A continuously variable zoom from 1x to 2x is realized.

After that, if the zoom switch 15 is continuously operated in the TELE direction, the state of the electronic zoom is changed from the zoom processing means 14 to the digital zoom state as shown in FIG. At the same time as switching to the 1x state corresponding to the angle of view of 960 pixels, a control signal for switching the angle of view of the optical lens 11 to 2 times from the zoom processing means 14 is supplied to the magnification switching means 16. The optical lens 11 is switched instantaneously so that the angle of view of the optical lens 11 becomes 1 to 2 times. As a result, the magnification of the photographing apparatus can maintain a double angle of view by changing the magnification of the optical lens 11. After that, by continuing the above-mentioned series of electronic zoom operations from 1x to 2x, it is possible to perform continuous zoom up to 4x angle of view.

This continuous zoom operation will be described with reference to FIG.

In the drawing, the optical magnification change of the optical lens 11 is indicated by a broken line A, the magnification change as an electronic zoom is indicated by a dashed-dotted line B, and the change of the total magnification as a zoom photographing device is indicated by a solid line. Indicated by C.

Now, when the zoom switch 15 is operated in the TELE direction from the WIDE end (1x), the optical lens 11 will maintain the 1x state, and the electronic zoom will change from 1x to 2x. By gradually changing the angle of view up to × 2, the zoom magnification of the entire zoom photographing device can be gradually changed from × 1 to × 2.

Then, when the electronic magnification of the electronic zoom reaches 2 times, a control signal for switching the magnification of the optical lens 11 from 1 times to 2 times is sent from the zoom processing means 14 to the magnification switching means 16. . Based on the signal from the magnification switching means 16, the optical lens 11 is instantly switched from the 1x state to the 2x state, and the electronic zoom magnification is changed from 2x to 1x. The switching is performed while maintaining the magnification of 2 times for the entire zoom photographing apparatus.

When the zoom switch 15 is further operated in the TELE direction, the angle of view is gradually changed from 1x to 2x with the electronic zoom from the overall magnification of 2x. become. Therefore, by increasing the electronic zoom magnification while maintaining the magnification of the optical lens 11 at 2 times, the zoom switch 15 can be changed while changing the zoom magnification of the entire device from 2 times to 4 times. It will reach the TELE end. Thus, by operating the zoom switch 15 from the WIDE end to the TELE end, it is possible to perform a zoom operation of 1 to 4 times.

When the zoom switch 15 is operated in the WIDE direction opposite to the TELE end from the 4x zoom state when the zoom switch 15 reaches the TELE end, the optical lens 11 remains in the 2x state. By using the electronic zoom, the angle of view can be gradually changed from 2 to 1 by the electronic zoom, and accordingly the zoom magnification of the entire apparatus can be gradually changed from 4 to 2 times.

Then, when the electronic zoom magnification reaches the position of 1 × by the electronic zoom operation and the magnification of the entire apparatus reaches 2 ×, the zoom processing means 14 switches the magnification of the optical lens 11 to 1 ×. Then, a switching signal is issued to the magnification switching means 16. By switching the optical lens 11 instantaneously from 2 × to 1 × by the switching signal from the magnification switching means 16 and changing the electronic zoom magnification from 1 × to 2 ×, the overall device becomes The electronic zoom and the magnification of the optical lens 11 are respectively switched while maintaining the magnification of 2 ×.

When the zoom switch 15 is further operated in the WIDE direction from this state, the optical The zoom ratio of the entire device changes from 2x to 1x while the angle of view is gradually changed from 2x to 1x with the electronic zoom while maintaining the 1x magnification of 1x1. Finally, you will reach the first WIDE end.

In these descriptions, the case where the zoom switch 15 is continuously operated from the WIDE end to the TELE end, and conversely, from the TELE end to the WIDE end is described, but the operation of the zoom switch 15 is described. Even if the operation direction is changed on the way, it is possible to set the desired zoom state by switching to the process in the opposite direction with the same operation.

In such a zoom photographing apparatus, an image signal based on imaging information is stored in an image sensor 12 having a number of pixels equal to or larger than a required resolution, and an image signal read from the image sensor 12 is converted into a pixel having a required resolution. Since the conversion is performed, the zoom processing can be performed without deteriorating the resolution.

In addition, since the image sensor 12 with the required resolution or higher is used, a still image is shot using all the pixels of the image sensor 12 and the resolution is increased due to problems such as an increase in data amount and processing speed. A digital camera that captures a moving image, a camera-equipped mobile phone that is limited by the resolution of the display device, or a still image with high pixels and a moving image that has been thinned out and converted to a standard format. When used in a device such as a video recording / reproducing device with a built-in camera, it is possible to perform moving image capturing processing without significantly degrading the resolution, so that an extremely effective zoom photographing device can be realized. Become.

In addition, using the readout signal obtained from the image sensor 12 having 1280 × 960 pixels of the required resolution or more, a camera signal output composed of 64 × 480 pixels is used. As a method to reduce the resolution to the required resolution, the explanation was given for the case of thinning out pixel signals using RG GB as one set.However, thinning out methods such as thinning out in other combinations and changing the thinning position for each field etc. For, other methods that do not impair the resolution are possible.

Further, for example, as shown in FIG. 8, it is also possible to adopt a method of adding and integrating the signals of 16 pixels for each color for each color. In the case of the method of adding and integrating signals as described above, the effect that the S / N ratio of the signal of each color can be improved can be obtained. It becomes possible to have.

Also, when interpolation processing is required during electronic zooming, as in the above case, it is assumed that a 16-pixel frame is placed at the ideal position, and signals corresponding to the area overlapping there are added for each color. By doing so, similar processing can be performed.

However, in this case, if the electronic zoom magnification is close to 2x, signals with a number of pixels close to 640 x 480 pixels will be captured, so the 16-pixel frame overlaps with its neighbors. Since there is a possibility that the resolution will be degraded due to the increase in the number of pixels, the thinning process in the 4-pixel frame by the control of the zoom processing means 14 or the like is performed before such a state where the overlap increases. In some cases, it may be better to perform switching processing so that control is performed again in the 16-pixel frame when the overlap is reduced.

Further, other combinations and combinations of pixels to be integrated are possible, such as a method in which the range of integration is a range in which the entire angle of view is divided by 320 × 240 virtual frames. The present invention is not limited to the embodiment, and other methods can be used as long as the process does not cause resolution degradation. In addition, a method of taking image signals of all pixels into the memory and processing them, or a predetermined arithmetic processing by the camera signal processing means 17 once using all the signals of 128 × 960 pixels Other methods, such as performing an electronic zoom process after performing the above, may be used. Here, an example of a CMOS sensor is given as the image sensor 12, but other image sensors such as CCD may be used.

Also, although there is some degradation in resolution, it is also possible to use a method using electronic zoom, which is a method of increasing the number of pixels in some sections.

Furthermore, in the above description, when the zoom switch 15 is operated to move the zoom operation in the TELE direction and in the WIDE direction, the magnification of the optical lens 11 is the same as the magnification of 2 times, and The zoom state is changed by switching the electronic zoom magnification at the same time. However, the optical lens has different zoom magnifications when shifting to the TELEWIDE direction and when shifting to the WIDE ^ TELE direction. It is also possible to simultaneously switch the magnification of the electronic zoom and the magnification of the electronic zoom.

That is, the change in magnification of the optical lens 11 used in FIG. 7, the change in magnification of the electronic zoom, and the change in magnification as a whole are shown in FIG. 9 using the same symbols A, B, and C, respectively. Thus, the switching point when switching the zoom from the WIDE end to the TELE direction is, for example, the electronic zoom magnification is 2.5 times, and the optical lens magnification is 1x. It is also possible to set to a different position. By switching the electronic zoom magnification from 2.5x to 1.25x and the optical lens magnification from 1x to 2x as soon as this position is reached, the zoom magnification of the entire device is increased to 2.5x. Is set to. Conversely, in the WIDE direction, from the state where the electronic zoom magnification is 1x and the optical lens magnification is 2x, set the electronic zoom magnification to 2x and the optical lens magnification to 1x, and zoom the entire device. A switching point can be set at a position where the magnification is doubled to achieve a change in zoom magnification.

With this configuration, compared to the case where the switching point in both the TELEWIDE direction and WID Έ → Ύ ELE direction is set to a point twice the optical lens magnification and the electronic zoom magnification, the TELE near the switching point In addition, it is possible to reduce the frequency of occurrence of switching at the time of repetitive zoom operation by the zoom switch 15 in the WIDE direction, thereby reducing the number of times of occurrence of switching noise.

Here, since the magnification of the electronic zoom is limited to 2.5 times, if the number of pixels of the image sensor 12 is 1280x960, the required resolution of 640x480 cannot be obtained if the magnification of the electronic zoom is 2 to 2.5 times. If the number of pixels of the image sensor 12 is selected to be (640 × 2.5) × (480 × 2.5) 1600 × 1200, it is possible to keep the required resolution of 640 × 480.

Further, as an embodiment for reducing noise at the time of switching, for example, in the above-described embodiment, the switching position of the predetermined zoom magnification is set to 2 times the overall magnification of the apparatus, and at this point the magnification of the optical lens 11 is unconditionally set. And the electronic zoom magnification are switched at the same time, but the switching of the optical lens 11 is controlled at such a timing that the lens magnification does not change during exposure based on the exposure timing information from the image sensor. In the zoom processing means 14, a signal to be generated is generated by the zoom processing means 14, and the magnification of the electronic zoom is changed with respect to the signal after switching the lens magnification newly obtained from the image sensor 12. Video mixing can be prevented, and noise at the time of switching can be reduced. Further, the image signal before switching the magnification of the optical lens 11 is held in the zoom processing means 14, and the held signal is used as the camera signal processing means 17 until the signal after switching the magnification of the lens is reliably obtained. It is also possible to switch the signal supplied to the camera signal processing means 17 when the signal after the switching processing of the lens magnification and the electronic zoom magnification is reliably obtained by continuously inputting With this configuration, it is possible to reduce the occurrence of noise when switching the magnification of the optical lens.

Furthermore, in the above-described embodiment, the optical lens having the 1 × and 2 × recitation ability and the electronic zoom processing means for continuously changing the magnification of 1 × to 2 × are used, and the required resolution is 6400 × 4. An explanation is given for a case where a signal of 80 pixels is obtained and the number of pixels of the image sensor to be used is set to 1280 × 960 pixels of (640 × 2) × (480 × 2). but it went, using an optical lens capable of switching the electronic zoom processing means for continuously changed up to the 1 × ~ a more than double in 1x and a times and a ^2-fold ... a ⁿ times multi-step, requiring By obtaining a signal with a resolution of XXY pixels and setting the number of pixels of the imaging device to be used to be equal to or more than aXXaY pixels, the same processing can be performed while maintaining the required resolution. In addition, the setting of the switching magnification and the number of switching steps of the optical lens, or the setting of the number of pixels of the image sensor and the required resolution can be variously set and combined, and are limited to only these embodiments. It goes without saying that various other applications and modifications are possible.

According to the present invention, by using an optical lens with a reduced number of magnification switching steps, a small-sized lens with a simple structure and low cost can be used, and a small magnification up to the switching magnification of the optical lens. In order to change the zoom magnification on the electronic zoom side, it is possible to keep the electronic zoom magnification at a low magnification, and to use an image sensor having a pixel number larger than the required resolution. The zoom magnification can be changed by adjusting the image signal obtained from the image sensor and changing the zoom magnification to the angle of view up to the required resolution. By using them together, it is possible to obtain a zoom photographing apparatus with little resolution © deterioration.

Claims

The scope of the claims

1. An optical lens whose magnification can be switched step by step,

An image pickup device for converting an optical image taken and formed by the optical lens into an image signal,

Reading control means for reading out image signals in a predetermined range of the image sensor in a predetermined order;

Zoom processing means for electronically zooming the image signal read by the reading control means and outputting it as a camera signal having a predetermined number of pixels;

Magnification switching means for switching the magnification of the optical lens by the zoom processing means;

A zoom photographing apparatus, wherein the image sensor has a larger number of pixels than the number of pixels of a camera signal output from the zoom processing unit.

2. The zoom photographing apparatus according to claim 1, wherein the magnification of both the optical lens and the electronic zoom is switched and the total magnification before and after the switching is switched so as to be constant.

3.1 times the magnification of the optical lens, a magnification, a ^2-fold, in the case of setting as switched et al a ³ times ... a ⁿ times, set the electronic zoom magnification to more than l~a times, claim 1 or 2 zooming equipment according is characterized in that setting the number of pixels of the image pickup element such that on a ² more than double the prescribed number of pixels of the camera signal outputted from the electronic zoom.

4. The zoom processing means increases the magnification of the electronic zoom and, when the magnification reaches the second-stage magnification a set in the optical lens, the magnification becomes a times as large as the current magnification. 4. The zoom photographing apparatus according to claim 1, wherein the magnification of the lens is switched and the electronic zoom magnification is switched to 1.

5. The zoom processing means reduces the electronic zoom magnification and, when the magnification reaches 1 ×, divides the current magnification by the second magnification a set for the optical lens. 4. The zoom photographing apparatus according to claim 1, wherein the magnification of the optical lens is switched so as to increase the magnification, and the electronic zoom magnification is switched to a.

6. The zoom photographing apparatus according to claim 1, wherein the electronic zoom magnifications at the plurality of magnification switching points are set to different values in the wide-angle and telephoto operation directions, respectively.

7. The image signal obtained by the image sensor from the image signal in the range where the angle of view is widened by the electronic zoom is thinned out and converted into a predetermined number of pixels. The zoom photographing device according to any one of the above.

8. The zoom lens according to any one of claims 1 to 6, wherein a partial integration process is performed on an image signal in a range in which the angle of view is widened by the electronic zoom to convert the image signal into a predetermined number of pixels. One-shot camera. .

9. The zoom photographing apparatus according to claim 1, wherein the switching timing of the optical lens is such that the magnification is switched at a timing during which the image sensor is not exposed.