JP7811319B2 - Zoom image capture device - Google Patents

Description

The present invention relates to a small, lightweight imaging device that can acquire high-magnification zoom images with reduced chromatic aberration.

Advances in solid-state imaging devices (sensors) and optical components used in video cameras, still cameras, and other devices have made it possible to create a wide variety of miniaturized, high-resolution imaging devices. This has expanded the variety of imaging options available, from high-resolution wide-angle images to super-telephoto images, and imaging devices are now used for a wide variety of purposes, from general photography to in-vehicle, medical, production equipment, military, commercial, and broadcasting applications, including image analysis, object detection, measurement and surveying, and surveillance and monitoring.

While the high integration of semiconductors and the miniaturization and high performance of component materials have enabled the lightweight and compact body of high-resolution imaging devices, physical constraints limit the lightweight and compactness of high-performance optical lenses. Zoom lenses are often used, particularly for photographing fast-moving animals, live sports broadcasts, and fast-moving objects. However, expanding the zoom range from wide-angle to telephoto images requires the use of extremely large and heavy zoom lenses. As a result, even though the body of an imaging device has become smaller and lighter, the overall size and weight of the imaging device cannot be reduced when a telephoto lens is attached.

Furthermore, when capturing a fast-moving subject using these imaging devices, as the image becomes telephoto (enlarged) through zooming, the subject moves out of the range of the enlarged image, making accurate capture difficult and forcing the user to zoom out again to search for the subject. In particular, video recording of ball sports, animal videos, flying objects, etc., broadcast coverage, and commercial and military surveillance camera recording require expertise and proficiency in instantaneously operating the zoom and focus of moving objects to enlarge and focus the subject.

As a zoom imaging device that aims to reduce the size and weight of such imaging devices, various techniques have been disclosed that use a prime lens (or fixed focus lens) to obtain an enlarged image by electronic zoom (or digital zoom) technology without using a zoom lens. Techniques have also been disclosed that increase the zoom magnification by using a plurality of prime lenses with different focal lengths to increase the magnification achieved by electronic zoom (e.g., Patent Documents 1 and 2).

However, such electronic zooming involves cropping and enlarging a portion of the image, resulting in a reduction in resolution. In other words, while a fixed-focal-length lens can be equipped with an electronic zoom function to achieve high magnification and capture images, it sacrifices resolution, creating challenges in ensuring high resolution. Furthermore, the missing portion of the zoomed image cannot be displayed or recorded, making it unsuitable for surveillance applications. These technologies are also inconvenient for capturing fast-moving objects or broadcasting sports events. Therefore, there is a demand for a compact, lightweight imaging device that can accurately capture fast-moving objects, making it easy to monitor, analyze, and analyze objects, and that can ensure high sensitivity and high resolution.

JP 2013-106289 A Japanese Patent Application Laid-Open No. 2005-31466

The present invention has been made in view of the above circumstances, and has as its main object to provide an imaging device as follows.
(1) A small, lightweight imaging device that has an expanded zoom range, high magnification, and is capable of acquiring high-sensitivity, high-quality images.
(2) An imaging device capable of acquiring high-quality images that can cope with resolution degradation even when using a magnification function using electronic zoom.
(3) An imaging device that has the function of accurately capturing a fast-moving object with simple operation and is capable of simultaneously displaying and recording missing images other than those cropped by electronic zoom.

In order to solve these problems and achieve the above-mentioned object, an imaging device of the present invention comprises a plurality of fixed focal lengths lenses, prism means for separating light beams acquired by the fixed focal lengths lenses , imaging elements for converting the light beams acquired through the prism means into video signals and outputting the signals, output means for outputting each of the video signals, electronic zoom means for electronically enlarging each of the video signals, switching means for switching the zoomed video signals enlarged by the electronic zoom means as continuous output images , and output means for outputting the zoomed video signals switched by the switching means , wherein any of the imaging elements is fixed to the prism means so as to be shifted from the other imaging elements by a half pixel pitch for pixel shifting, and each of the video signals is output via an up-converter or down-converter for output image format conversion, and each of the video signals and the zoomed video signal are output simultaneously from the respective output means and displayed on the same screen .

In addition, the imaging device of the present invention can also be configured so that the multiple prime lenses are composed of n (n is 2 or more) prime lenses, and the focal length of the nth prime lens is the product of the focal length of the n-1th prime lens and the n-1th electronic zoom magnification.

The imaging device of the present invention can also be configured such that the prism means has a prism configuration that separates the visible light band for use by two single-plate imaging elements.

The imaging device of the present invention can also be configured so that the prism means has a prism configuration that separates the visible light band for three imaging elements of a blue light band, a red light band, and a green light band.

In addition, the imaging device of the present invention can also be configured so that the prism means has a prism configuration that separates the visible light band into a blue light band, a red light band, a first green light band, and a second green light band for four imaging elements.

The imaging device of the present invention can also be configured so that the plurality of fixed focal length lenses are arranged on a pan-tilt head that can rotate up and down and left and right.

According to the present invention, a high-magnification zoom function is achieved by switching between images captured by electronic zoom using multiple fixed-focal-length lenses with different focal lengths, and the images captured by each fixed-focal-length lens and the image captured by the zoom function are output as video signals, thereby achieving a compact, lightweight imaging device without using high-magnification zoom lenses. Because the imaging device is constructed using only fixed-focal-length lenses, chromatic aberration is reduced compared to images captured by a zoom lens, and degradation of peripheral illumination and peripheral resolution is improved. Furthermore, pixel shifting allows the use of an imaging element with larger pixels, enabling higher sensitivity and increasing resolution, thereby maintaining image quality that can withstand the degradation of resolution associated with electronic zoom magnification.

In addition, by using multiple prime lenses ranging from wide-angle to telephoto lenses and applying an electronic zoom function to each, it becomes possible to simultaneously acquire wide-angle to telephoto images from the multiple prime lenses and zoom images and display them as simultaneous moving images on the display, thereby always displaying the surrounding images cropped by the zoom images, and displaying and recording not only the zoomed images but also all images of a continuous event. Furthermore, by utilizing such simultaneous multiple image display, accurate subject capture of a fast-moving object and rapid zoom photography can be performed with simple operations even by an unskilled technician.

1 is a block diagram illustrating an example of the configuration of an imaging device according to the present invention; FIG. 2 is an explanatory diagram showing an example of the configuration of an image processing block according to the present invention. 1A and 1B are explanatory diagrams showing examples of pixel-shifting light beam separation prisms according to the present invention; FIG. 10 is an explanatory diagram showing the relationship between the magnification of electronic zoom and the resolution. 1 shows an example of the configuration of a pan-tilt head used in the system according to the present invention. 1 is an explanatory diagram showing a method for capturing and photographing a fast-moving object according to the present invention;

Hereinafter, embodiments of an optical system, an image processing device, and an imaging device related to the present invention will be described in detail with reference to the drawings. Note that any explanatory diagrams and drawings described in the following examples are drawn as outlines or schematic diagrams for the purpose of explaining the present invention, and the actual dimensions and shapes are not particularly limited. Furthermore, the system configurations, block diagrams, dimensions, materials, shapes, their relative positions, and use examples used in the examples are not intended to limit the technical scope of the invention to those alone, unless otherwise specified.

FIG. 1 is an explanatory block diagram showing the entire embodiment of an imaging device according to the present invention, and FIG. 2 is an explanatory block diagram of a series of signal processing steps shown in FIG. 1. In FIG. 1, the imaging device has a lens block 10 made up of a plurality of fixed focal length lenses. FIG. 1 shows an example of lens block 10 made up of three fixed focal length lenses: a wide-angle lens block 11, a medium-angle lens block 12, and a telephoto lens block 13. Each lens block can be configured with a single sensor, but it can also be configured to support a two-, three-, or four-chip sensor by using a beam separation optical system made up of a prism or the like, thereby achieving high resolution by pixel shifting.

In the lens blocks 10 (wide-angle lens block 11, medium-angle lens block 12, and telephoto lens block 13), images focused by each lens are converted into electronic signals by image sensor sensors, which output the electronic signals and send the respective video signals to a signal processing block 20. The signal processing block 20 has wide-angle lens signal processing means 21, medium-angle lens signal processing means 22, and telephoto lens signal processing means 23, which correspond to the respective lens blocks. Each of the signal processing blocks 20 performs image processing using a pixel shift processing means 24 and an ISP (image signal processor) 25, and sends the processed image signals to the subsequent electronic zoom processing means 30. The wide-angle, medium-angle, and telephoto image signals are output to a display device (monitor) as a wide-angle image output, a medium-angle image output, and a telephoto image output, respectively, and are also sent to the subsequent electronic zoom block 30.

As shown in FIG. 2 , each signal processing block 20 performs pixel shift processing using a pixel shift processing means 24, and then performs image processing using an ISP 25. In the pixel shift processing means 24 shown in FIG. 2 , as described later in the lens block 10, one of the image sensors is fixed at a diagonal offset of half a pixel pitch (half phase) relative to the other image sensors, and the Y signal sample points of each image sensor are extracted and pixel shift processed to increase the resolution of the Y signal. The ISP 25 is an image signal processor that performs a series of image processing, such as noise reduction, gain correction, linear matrix correction, detail correction, and gamma correction, on the image signals obtained by each image sensor, and outputs the processed signals. The wide-angle electronic zoom means 31, medium-angle electronic zoom means 32, and telephoto electronic zoom means 33 in the electronic zoom block 30 each perform electronic zooming of the input image in accordance with a control signal from an electronic zoom control means 41.

To ensure a bright F-number on the telephoto side of a zoom lens, the diameter of the front lens must be increased, so in reality, the F-number remains slow. Therefore, in order to increase sensitivity, the element area on the sensor side must be increased, but since the number of elements cannot be increased within the limited image size, a method is used to achieve high sensitivity while increasing resolution by shifting the green pixels (G) diagonally relative to the large red pixels (R) and blue pixels (B), allowing the use of sensors with large pixels, making it possible to achieve high sensitivity and high resolution.

The electronic zoom is limited to a magnification of about 4x compared to the basic image of a fixed focal length lens. Although it is possible to achieve a larger magnification than this, as described below, an example with a magnification of 4x is considered. Furthermore, in design, it is also possible to provide an overlap range by combining multiple fixed focal length lenses and electronic zoom. This overlap allows for image quality adjustments such as alpha blending of the output from the front and rear lenses to compensate for changes that occur when switching lenses. This overlap range is not particularly specified and is a design matter.

The magnification limit of electronic zoom is mainly due to the reduction in resolution caused by cropping and enlarging the image during zooming. If the magnification ratio of electronic zoom is assumed to be 4x, and the wide-angle lens has a fixed focal length fw of 10 mm, the medium-angle lens has a fixed focal length fm of 40 mm, and the telephoto lens has a fixed focal length ft of 160 mm, then a zoom lens can be configured that continuously covers the ranges of 10 to 40 mm for the wide-angle lens, 40 to 160 mm for the medium-angle lens, and 160 to 640 mm for the telephoto lens. In other words, by continuously switching between images enlarged (or reduced) using the electronic zoom function, a zoom lens image equivalent to 10 to 640 mm (64x magnification) can be obtained.

In other words, a zoom lens with an expanded zoom range is formed by contiguousing the electronic zoom range of a single focal length lens and configuring it with multiple single focal length lenses. A continuous zoom effect can be obtained by configuring multiple (n, n is 2 or more) single focal length lenses such that the focal length (fn) of the nth single focal length lens is the product of the focal length of the (n-1)th single focal length lens and the (n-1)th electronic zoom magnification (m).

When the zoom magnification (angle of view) is continuously changed from the maximum wide-angle image (maximum wide area) to the maximum telephoto image (maximum enlarged area) by zooming in (enlarging the image), the zoom control means 41 provides a magnification change signal to the wide-angle electronic zoom means 31 to change the image from 10 to 40 mm equivalent, then provides a magnification change signal to the medium-angle electronic zoom means 32 to change the image from 40 to 160 mm equivalent, and then provides a magnification change signal to the telephoto electronic zoom means 33 to change the image from 160 to 640 mm equivalent, thereby successively acquiring zoom-in (image enlargement) image signals by switching the selector means 40 sequentially from the wide-angle image to the medium-angle image and then to the telephoto image. Conversely, when zooming out (reducing the image) from the maximum telephoto image (maximum enlarged area) to the maximum wide-angle image (maximum wide area), the above operation is reversed to acquire successive zoom-out images.

An image adjusting means 42 for adapting the image output signal to the image display monitor may also be provided downstream of the selector means 40. This image adjusting means 42 is composed of an up/down converter or the like and adapts the zoom output signal to the monitor format or the compression format of the recording device. The zoom image signal switched by the selector means 40 may be sent directly as the output image, but depending on the purpose of use, an image quality adjusting means may also be provided at this stage to perform contour compensation, alpha blending of the front and rear lens outputs to compensate for changes due to lens switching, etc.

The zoomed image thus obtained is displayed on the zoom display screen of the monitor. Furthermore, the wide-angle image, medium-angle image, and telephoto image are output to be displayed on the wide-angle image monitor, medium-angle image monitor, and telephoto image monitor, respectively. This image display means can simultaneously display moving images as a multi-split screen on the monitor screen 100 as shown in FIG. 6(A), or display them in a picture-in-picture format as shown in FIG. 6(B). Depending on the intended use, each image may be displayed separately on a separate monitor. Furthermore, instead of providing an electronic zoom function to all fixed-focus lenses, it is also possible to provide an electronic zoom function only to a specific lens (e.g., a telephoto lens) to enlarge or reduce only a specific image portion to obtain an appropriate image.

In an imaging device that performs zoom photography using a combination of multiple fixed focal length lenses and electronic zoom, a change in resolution occurs as the electronic zoom changes, as shown in Figure 4. In the above-described example, with a wide-angle lens focal length (10 mm), a medium-angle lens focal length (40 mm), and a telephoto lens focal length (160 mm), if the electronic zoom magnification is 4x, the horizontal resolution becomes 1/4 as the electronic zoom magnification is zoomed from 1x to 4x. Figure 4(A) shows the change in horizontal resolution when a zoom lens with a focal length of 10mm to 640mm is configured using a 4K resolution image sensor.

Furthermore, when the electronic zoom magnification is 2x, the horizontal resolution changes to 1/2, as shown in Figure 4(B). In this case, to configure a zoom lens with focal lengths from 10 mm to 640 mm using a combination of fixed focal length lenses, the lens must be configured using a combination of six fixed focal length lenses, with focal lengths of L1 (10 mm), L2 (20 mm), L3 (40 mm), L4 (80 mm), L5 (160 mm), and L6 (320 mm).

For this reason, the present invention is configured to achieve high resolution and high sensitivity by pixel shifting so as to be adaptable to changes in resolution. Pixel shifting methods include: shifting one of two image sensors by half a pixel pitch in the horizontal and vertical directions to acquire an image signal, and combining it with the image signal of the other image sensor that is not pixel shifted to increase the resolution of the Y sample signal; or shifting the pixel by changing the thickness or inclination of an optically transparent glass parallel plate between the lens and the image sensor to project the optical axis to a pixel-shifted position in various ways. Either method is acceptable. In the present invention, a prism configuration such as that shown in FIG. 3 is used to shift one image sensor by half a pixel relative to the other image sensor to acquire an image. Utilizing this pixel shifting allows the use of a sensor with larger pixel size, enabling higher sensitivity and resolution.

FIG. 3A shows an example of a two-chip pixel shift configuration. An image focused by a fixed focal length lens 60 is separated into two beams by a beam splitter prism 61, and image signals are acquired by two single-chip image sensors 62 and 63. One of the image sensors is fixed with a half-pixel pitch offset from the other. The pixel shift is performed diagonally. The signals acquired by the pixel shift method are read out from the outputs of the respective image sensors by respective signal processing means 64, and output as video signals. The signal processing means 64 combines and outputs the video signals of the respective image sensors. The output signal can be acquired as a high-resolution output in which the resolution of the Y signal sample points is increased by pixel shifting.

3(B) shows an example of a prism configuration for image acquisition using pixel offset in a three-plate system. An image focused by a fixed focal length lens 70 is separated into three light beams by a beam splitter prism 71, and image signals are acquired by three image sensors 72 (B), 73 (R), and 74 (G). The image sensors 72, 73, and 74 are black-and-white sensors that convert the wavelength-separated light band components by the prism 71 into electrical signals. At this time, by fixing the green image sensor with a pixel pitch offset from the other image sensors, it is possible to obtain an output with increased resolution for the extracted Y signal sample points.

FIG. 3C shows an example of a prism configuration for image acquisition using pixel offset in a four-plate system. An image focused by a fixed-focus lens 80 is separated into four beams by a beam splitter prism 81, and image signals are acquired by four image sensors 82, 83, 84, and 85. Image sensor 82 extracts the blue component (B) using a blue image sensor, and image sensor 83 extracts the red component (R) using a red image sensor. A red video signal (R) is output by a signal processing circuit 87. Image sensors 84 and 85 each extract two green components (G1 and G2) acquired from the green component (G) using a beam splitter or the like. One of these two green image sensors is fixed with a pixel pitch offset from the other, forming a so-called dual green pixel offset configuration. This configuration enables a Y signal output with increased resolution.

The beam splitter prism and signal processing means suitable for acquiring such pixel-shifted images are selected from beam splitter prisms for multispectral cameras, such as two-plate, three-plate, and four-plate types, depending on the purpose of use and needs, and are configured to increase the resolution of the images acquired for each fixed-focus lens (wide-angle, medium-angle, and telephoto lens).

High-sensitivity zoom lenses are expensive and difficult to obtain, and they also have aberrations that change depending on the focal length, but single-focus lenses not only have less aberration, but the aberrations are fixed, so they do not change with electronic zoom.As a result, even with pixel shifting, chromatic aberration is reduced compared to images captured with a zoom lens, and peripheral illumination and resolution are improved.

Recent advances in imaging element development have made it possible to use imaging elements with high pixel counts and fine pitches, resulting in high sensitivity. However, it is possible to achieve higher resolution by using an imaging element with a larger pixel size and improved sensitivity, even if the pixel count is still small, through pixel shifting using a prism. For example, by using a high-sensitivity 2K (HD) imaging element to perform pixel shifting of a 2K-equivalent image, it is possible to obtain an image with a Y signal resolution equivalent to 4K at high sensitivity, thereby enabling a configuration that can tolerate a reduction in resolution due to electronic zooming. In other words, by using the present invention in combination with a fixed-focal-length lens, it is possible to obtain high-sensitivity images that not only overcome the issues of the large size and weight of zoom lenses, but also improve the sensitivity using a large-pixel imaging element, thereby improving the lost resolution and reducing the issues of chromatic aberration and reduced peripheral resolution caused by zoom lenses.

Next, we will discuss how to use an imaging device configured as described above to accurately capture a fast-moving subject and zoom in (telephoto) or zoom out (wide-angle). When photographing flying objects or during live baseball or golf coverage, etc., situations arise where the fast-moving object is lost while zooming in (telephoto), and the user must first zoom out (wide-angle) to confirm the object, then zoom in (telephoto) again to capture it. This type of zoom operation requires skill and experience, as the greater the telephoto magnification, the more difficult it is to accurately capture the subject.

FIG. 5 shows an example of the configuration of a motorized pan-tilt head mounted with an imaging device according to the present invention. The pan-tilt head 90 comprises a horizontally rotatable platform 92 mounted on a fixed support base 91, and a vertically rotatable camera housing 95 connected to a support 93 mounted on the horizontally rotatable platform via a vertically rotatable shaft 94. The camera housing 95 houses a wide-angle fixed lens 96, a medium-angle fixed lens 97, and a telephoto fixed lens 98, all of which face the same direction. The pan-tilt head 90 is electrically rotatable in the up, down, left, and right directions relative to the fixed support base 91, and its direction is controlled by wire or wirelessly to track a subject. The camera housing 95 is also equipped with a thermal camera (or infrared camera) 99, which captures infrared images in addition to visible light images, enabling versatile imaging applications such as night vision and temperature sensing.

Such a pan-tilt head 90 is equipped with the imaging device according to the present invention, and the output signal of this imaging device can be configured to simultaneously display a wide-angle image 101, a medium-angle image 102, a telephoto image 103, and a zoom image 104 as a multi-split screen on a monitor screen 100, as shown in FIG. 6A, or to display a zoom image 104 within the wide-angle image 101 in a picture-in-picture format, as shown in FIG. 6B. Each image can also be displayed independently on multiple monitors. On the multi-screen monitor screen 100 of FIG. 6A, the wide-angle image 91, the medium-angle image 92, and the telephoto image 93 are each displayed as a reference image of a fixed focal length lens. This reference image is an image at infinity focus for each fixed focal length, without using electronic zoom. The pan-tilt head 90 is operated to track and control a subject while monitoring the monitor screen 100.

In Figure 6(C), the monitor screen 100 displays a wide-angle screen 101. This wide-angle screen 101 and the operator can interactively control and instruct using a method such as a touch panel, and when the operator wants to zoom in on a high-speed flying object on the screen, the camera operator issues a zoom-in instruction on the wide-angle screen. This zoom-in instruction can be issued in any of the following ways.
(1) Use the marker on the screen (or touch your hand) to move to the subject you want to zoom in on, and a single click will start the electronic zoom of the telephoto lens zooming in on the clicked subject (enlarging the screen). When the desired screen is enlarged, double-clicking will end the zooming.
(2) Move the marker on the screen from the clicked location to the desired enlarged image, and then zoom in (enlarge) the electronic zoom of the telephoto lens toward the rectangle enclosed by the clicked location.
(3) By encircling the desired area of the enlarged image with the marker on the screen, the electronic zoom of the telephoto lens is zoomed in (enlarged) toward the enclosed square area.

When a zoom-in (enlargement) command is given on the monitor screen 100, the pan-tilt head 90 is controlled so that the telephoto lens captures the center of the enlarged image. Furthermore, once the enlarged image is confirmed, the camera can be designed to automatically track a fast-moving object (moving subject). Such automatic tracking and autofocusing of fast-moving objects can be achieved by known techniques.

The zoom photography method of the present invention allows users to simultaneously display and check telephoto, medium-angle, and wide-angle images using a zoomable screen. While viewing the entire wide-angle image on the monitor screen, users can instantly zoom in by touching or clicking on a fast-moving subject. This allows for more accurate zooming, eliminating the need to return to the wide-angle screen or adjust the zoom range to find the subject again, as was previously required. This functionality makes the device effective for tracking balls in golf and baseball broadcasts, and for high-speed tracking and capturing of fast-moving objects in surveillance cameras. Furthermore, because multiple single-focus lens images (wide-angle, medium-angle, and telephoto images) are constantly output simultaneously in addition to zoomed images, it is possible to simultaneously obtain image information necessary for capturing and recording surrounding conditions and movements, particularly in surveillance cameras and image analysis cameras, thereby providing an extremely convenient imaging device.

The imaging device and imaging method of the present invention enable a compact and lightweight imaging device using a single focal length lens without using a high-magnification zoom lens, resulting in reduced chromatic aberration and improved peripheral illumination compared to images captured with a zoom lens. Furthermore, by configuring an imaging system using the imaging device of the present invention, telephoto, medium-angle, wide-angle, and zoomed images can be simultaneously displayed and viewed, enabling accurate subject capture of fast-moving objects and rapid zoom photography with simple operations, even for non-experts. This enables a wide range of applications, including surveillance cameras, vehicle-mounted cameras, weather cameras, aircraft cameras, and endoscopic cameras, expanding the scope of industrial applicability across a wide range of applications, including commercial, consumer, industrial, and military.

10 Lens block 11 Wide-angle lens block 12 Medium-angle lens block 13 Telephoto lens block 20 Signal processing block 21 Wide-angle signal processing 22 Medium-angle signal processing 23 Telephoto signal processing 24 Pixel shift processing means 25 ISP (Image signal processor)
30 Electronic zoom block 31 Wide-angle electronic zoom means 32 Medium-angle electronic zoom means 33 Telephoto electronic zoom means 40 Selector means 41 Zoom control means 42 Converter, image quality adjustment means 60, 70, 80 Single focus lens 61 Two-plate light beam splitter prism 71 Three-plate light beam splitter prism 81 Four-plate light beam splitter prism 90 Pan/tilt head 92 Horizontal (left and right) direction rotation base 94 Vertical (up and down) direction rotation axis 95 Camera housing 96 Single focus wide-angle lens 97 Single focus medium-angle lens 98 Single focus telephoto lens 99 Thermal camera 100 Monitor screen

Claims (7)

a plurality of fixed focal length lenses having different focal lengths;
a prism means for separating the light beam obtained from the fixed focal length lens ;
an imaging element that converts the light beam acquired through the prism means into a video signal and outputs the video signal;
output means for outputting video signals from the respective imaging elements;
a switching means for switching between the zoomed image signals enlarged by the electronic zoom means as successive output images ;
an output means for outputting the zoom image signal switched by the switching means,
any one of the imaging elements is fixed to the prism means so as to be shifted from the other imaging element by a half pixel pitch for pixel shifting;
Each of the video signals is output via an up-converter or a down-converter for output image format conversion;
an image pickup apparatus, wherein the respective video signals and the zoomed video signal are simultaneously outputted from the respective output means and displayed on the same screen ; the plurality of fixed focal length lenses are composed of n fixed focal length lenses (n is 2 or more);
2. The imaging device according to claim 1, wherein the focal length of the n-th fixed focal length lens is the product of the focal length of the (n-1)th fixed focal length lens and the (n-1)th electronic zoom magnification. 2. The imaging device according to claim 1 , wherein said prism means has a prism structure for separating visible light bands for use by two single-plate imaging elements. 2. The imaging device according to claim 1 , wherein said prism means has a prism configuration for separating a visible light band for three imaging elements, one for a blue light band, one for a red light band, and one for a green light band. 2. The imaging device according to claim 1, wherein the prism means has a prism configuration that separates the visible light band into a blue light band, a red light band, a first green light band, and a second green light band for four imaging elements. 2. The imaging device according to claim 1 , wherein the plurality of fixed focal length lenses are arranged on a pan-tilt head that is rotatable in the up-down and left-right directions. a display means for displaying the respective video signals and the zoom video signal ;
the display means is configured by a touch panel,
2. The imaging device according to claim 1 , wherein the zoom video signal is used to enlarge and display a specified portion on the screen of the touch panel by specifying the specified portion on the screen of the touch panel.