A compact integral three-dimensional (3D) imaging device for capturing high resolution 3D images has been developed that positions the lens array and image sensor close together. Unlike the conventional scheme, where a camera lens is used to project the elemental images generated by the lens array onto the image sensor, the developed device combines the lens array and image sensor into one unit and makes no use of a camera lens. In order to capture high resolution 3D images, a high resolution imaging sensor and a lens array composed of many elemental lenses are required, and in an experimental setup, a CMOS image sensor circuit patterned with multiple exposures and a multiple lens array were used. Two types of optics were implemented for controlling the depth of 3D images. The first type was a convex lens that is suitable for compressing a relatively large object space, and the second was an afocal lens array that is suitable for capturing a relatively small object space without depth distortion. The objects captured with the imaging device and depth control optics were reconstructed as 3D images by using display equipment consisting of a liquid crystal panel and a lens array. The reconstructed images were found to have appropriate motion parallax.
We are currently researching a next-generation broadcasting system called Super Hi-Vision (SHV). We have proposed
the following video parameters for SHV: 33-million-pixel (33M-pixel) resolution, 120-Hz frame frequency, and wide
gamut color system. In order to capture the SHV images, we investigate a 33M-pixel image-capturing system operable at
a frame frequency of 120 Hz. The system consists of four CMOS image sensors that can not only output 33M-pixel at
60-Hz frame frequency but also output half of the 33M-pixel in either odd or even lines at 120-Hz frame frequency. Two
image sensors are used for the green channel (G1 and G2), and the other two are assigned to each of the red and blue
channels. The G1 sensor outputs the odd lines, while the G2 sensor outputs the even lines. A combination of G1 and G2
outputs 33M-pixel green images. The red and blue sensors scan odd lines and even lines, respectively. Subsequently, the
unscanned lines are interpolated in the vertical direction. In addition, we design a prism for wide color gamut
reproducibility. We develop a prototype and evaluate its resolution, image lag, and color reproducibility. The
performance of the proposed system is found to be satisfactory for capturing 33M-pixel images at 120 Hz.
Integral 3D television based on integral imaging requires huge amounts of information. Earlier, we built an Integral 3D
television using Super Hi-Vision (SHV) technology, with 7680 pixels horizontally and 4320 pixels vertically. Here we
report on an improvement of image quality by developing a new video system with an equivalent of 8000 scan lines and
using this for Integral 3D television. We conducted experiments to evaluate the resolution of 3D images using this
prototype equipment and were able to show that by using the pixel-offset method we have eliminated aliasing that was
produced by the full-resolution SHV video equipment. As a result, we confirmed that the new prototype is able to
generate 3D images with a depth range approximately twice that of Integral 3D television using the full-resolution SHV.
To develop an ultrahigh-definition television (UHDTV) camera-with a resolution 16 times higher than that of HDTV
resolution and a frame rate of 60 Hz (progressive)-a compact and high-mobility UHDTV camera using a 33M-pixel
CMOS image sensor to provide single-chip color imaging was developed. The sensor has a Bayer color-filter array
(CFA), and its output signal format is compatible with the conventional UHDTV camera that uses four 8M-pixel image
sensors. The theoretical MTF characteristics of the single-chip camera and a conventional four-8M-pixel CMOS camera
were first calculated. A new technique for Bayer CFA demosaicing used for the single-chip UHDTV camera was then
evaluated. Finally, a pick-up system for single-chip imaging with a 33M-pixel color CMOS image sensor was
measured. The measurement results show that the resolution of this is equivalent to or surpasses that of the conventional
four-8M-pixel CMOS camera. The possibility of a practical compact UHDTV camera that makes use of single-chip
color imaging was thereby confirmed.
We have been developing an ultra high definition television (UHDTV) system with a 7,680 horizontal by 4,320 vertical pixel resolution and a 60 Hz frame rate. This system, which is called Super Hi-vision (SHV), is expected to serve the next generation of broadcasting services. We have just completed the world's first imaging equipment that is capable of capturing video at a full SHV resolution. In designing this equipment, we decided to develop three new devices, taking into account the camera performance and the ease of implementation. First, we developed a 33-megapixel CMOS image sensor. Its pixel size of 3.8 &mgr;m sq. retained the dynamic range of the sensor above 60 dB even with a 3-transistor pixel structure. Second, a fixed focal length lens was developed to create an adequate MTF right up to the limiting resolution of the sensor. Third, we developed a signal-processing device capable of handling 72 Gbps signals and cascading boards to expand the process. SHV images with a modulation of 20% at the Nyquist frequency were obtained by using these three key technologies.
We developed an experimental ultrahigh-definition color
video camera 7680H4320V pixels using four 8-million-pixel
charge-coupled devices (CCDs) to increase the camera’s resolution.
This involves attaching four CCDs to a special color separation
prism. Two CCDs are used for the green image; the other two
are used for the red and blue images. Our prototype camera attains
a limiting resolution of more than 2700 television lines, both horizontally
and vertically. Camera sensitivity is F/2.8 at 2000 lux, with a
luminance signal dark-noise level of approximately 50 dB in high
definition television format. To analyze camera performance, we estimated
the spatial position error between the two green CCDs and
the chromatic aberration. Based on these estimations, the cause of
resolution deterioration and ways to improve resolution are
The integral method enables observers to see 3D images like real objects. It requires extremely high resolution for both
capture and display stages. We present an experimental 3D television system based on the integral method using an
extremely high-resolution video system. The video system has 4,000 scanning lines using the diagonal offset method
for two green channels. The number of elemental lenses in the lens array is 140 (vertical) × 182 (horizontal). The
viewing zone angle is wider than 20 degrees in practice. This television system can capture 3D objects and provides full
color and full parallax 3D images in real time.
We developed an experimental single chip color HDTV video image acquisition system with 8M-pixel CMOS
image sensor. The imager has 3840 (H) × 2160 (V) effective pixels and built-in analog-to-digital converters, and its
frame rate is 60-fps with progressive scanning. The MTF characteristic we measured with this system on luminance
signal in horizontal direction was about 45% on 800 TV lines. This MTF was better than conventional three-pickup
broadcasting cameras, therefore the enhancement gain (the "enhancement area" in MTF) of the 8M single-chip HDTV
system was about a half of the three-pickup cameras. We also measured the color characteristics and corrected the color
gamut using matrix gain on primary colors. We set the color correction target similar to that of three-pickup color
cameras in order to use multiple cameras to shoot for broadcasting, where all cameras are controlled in the same manner.
The color error between the single-chip system and three-pickup cameras after the correction became 2.7, which could
be useful in practice.
We have developed color camera for an 8k x 4k-pixel ultrahigh-definition video system, which is called Super Hi- Vision, with a 5x zoom lens and a signal-processing system incorporating a function for real-time lateral chromatic aberration correction. The chromatic aberration of the lens degrades color image resolution. So in order to develop a compact zoom lens consistent with ultrahigh-resolution characteristics, we incorporated a real-time correction function in the signal-processing system. The signal-processing system has eight memory tables to store the correction data at eight focal length points on the blue and red channels. When the focal length data is inputted from the lens control units, the relevant correction data are interpolated from two of eights correction data tables. This system performs geometrical conversion on both channels using this correction data. This paper describes that the correction function can successfully reduce the lateral chromatic aberration, to an amount small enough to ensure the desired image resolution was achieved over the entire range of the lens in real time.
We have developed an experimental single-chip color HDTV image acquisition system using 8M-pixel CMOS image sensor. The sensor has 3840 × 2160 effective pixels and is progressively scanned at 60 frames per second. We describe the color filter array and interpolation method to improve image quality with a high-pixel-count single-chip sensor. We also describe an experimental image acquisition system we used to measured spatial frequency characteristics in the horizontal direction. The results indicate good prospects for achieving a high quality single chip HDTV camera that reduces pseudo signals and maintains high spatial frequency characteristics within the frequency band for HDTV.
We describe a precise alignment method of attaching imagers to a prism to produce an ultra-high definition color camera system. We have already developed a prototype camera with 4-k scanning lines using this alignment method.
To increase its spatial resolution, this camera has four 8-megapixel imagers (GGBR), which are attached to a prism with a half-pixel pitch offset so that their pixel arrangement is equivalent to that of a single-chip color-imaging sensor with a Bayer-pattern color filter. The precision of their positioning influences the resolution of the reproduced images. The small pixels in the latest imager make it more difficult to maintain precise imager positions. A precise alignment method for attaching imagers to prism is therefore essential for developing a camera system with high resolution. We propose a method with high detectivity using a sinusoidal pattern chart that easily reproduced by one imager, and a signal process. Images from this camera can attain a limiting resolution of more than 3200 TV lines.
An experimental ultrahigh-definition color video camera system with 7680(H) × 4320(V) pixels has been developed using four 8-million-pixel CCDs. The 8-million-pixel CCD with a progressive scanning rate of 60 frames per second has 4046(H) × 2048(V) effective imaging pixels, each of which is 8.4 micron<sup>2</sup>. We applied the four-imager pickup method to increase the camera’s resolution. This involves attaching four CCDs to a special color-separation prism. Two CCDs are used for the green image, and the other two are used for red and blue. The spatial image sampling pattern of these CCDs to the optical image is equivalent to one with 32 million pixels in the Bayer pattern color filter. The prototype camera attains a limiting resolution of more than 2700 TV lines both horizontally and vertically, which is higher than that of an 8-million-CCD. The sensitivity of the camera is 2000 lux, F 2.8 at approx. 50 dB of dark-noise level on the HDTV format. Its other specifications are a dynamic range of 200%, a power consumption of about 600 W and a weight, with lens, of 76 kg.
A wide dynamic range camera for high picture quality use is proposed. The camera is equipped with a novel optical beam splitting system. It first divides incident light into two different intensity lights. Small intensity light is taken by a single-chip color imager. The other large intensity light is further led to a tri-color prism and taken by three imagers. These functions are integrated into one-piece optical block, which is suited for 2/3-inch optical format standard. An experimental HDTV camera has been developed. The exposure ratio was set as 9:1. A high exposure image is taken by three 2M-pixel CCDs and a low exposure image is taken by a single-chip color 2M-pixel CCD with an on-chip stripe color filter. The results have shown that the validity of the proposed method for obtaining wide dynamic range images with high picture quality.