JP7445904B2 - Video output device, video output method, and video output system - Google Patents

Description

The present disclosure relates to a video output device, a video output method, and a video output system used in a video display system suitable for displaying video having a relatively high frame rate.

A video display system that processes and transmits video signals of moving images and displays the video on a display device is designed to operate at a frame rate of 60 fps (frames per seconds) or less, taking human vision into consideration. It is common that In such a video display system, a certain amount of delay may occur in the entire system due to the execution of imaging, image processing, and transmission processing until the video acquired by the imaging device is displayed on the display device. become. For example, when the frame rate is 60 fps, the time per frame is about 16.6 ms, and a delay of about 100 ms may occur as a delay in video display.

The above-described delay in displaying an image relative to the output of an image captured by an imaging device can adversely affect the operation of the system. For example, when controlling a robot arm to grasp an object that moves irregularly while viewing images from a remote location, it is necessary to eliminate the delay in image display because image delays can hinder stable operation. desired. Eliminating video display delays is also beneficial in video display systems used for endoscopic surgery and remote surgery that utilize real-time video, remote control of disaster relief robots, and the like.

On the other hand, a technology that suppresses the delay in video display by applying a relatively high frame rate (for example, 480 fps) to the video is also envisioned, but simply increasing the frame rate would reduce the amount of transmission and calculation. This will lead to an increase in the amount.

As a technique for suppressing the amount of transmission while maintaining high resolution of images, for example, with respect to images taken by surveillance cameras, we focus on areas such as the areas near doors where people enter and exit, and increase the focus on the surveillance areas that we want to monitor. There is a known method that displays the area at a frame rate and transmits areas such as plants and walls that serve as the background of the monitored area at a low frame rate in consideration of effective use of network bandwidth. There is.

JP2008-219484A

In the conventional technology described in Patent Document 1, a high frame rate of about 30 fps is assumed. Here, if a higher frame rate (for example, 480 fps) is applied to maintain the high resolution of the video, even if the high frame rate is applied to a part of the image such as the surveillance area of interest. , an increase in the amount of transmission and calculation can be a problem.

The present disclosure makes it possible to suppress an increase in the amount of video transmission and the amount of calculation while suppressing a deterioration in the quality of the displayed image when acquiring a video having a relatively high frame rate and transmitting it to a display device. The purpose of the present invention is to provide a video output device, a video output method, and a video output system.

The present disclosure includes a noise adding unit that adds noise to the first video data based on a luminance value of the input first video data; a modulation unit that converts the video data into second gradation display video data having a smaller gradation value than the first gradation obtained from the video data; and a video output unit that outputs the second gradation display video data. When the brightness value of the first video data is in a low brightness region, the noise adding section adds noise generated in a widely set amplitude range, and increases the brightness value of the first video data. Provided is a video output device that adds the noise generated in a narrowly set amplitude range when the noise is in a high brightness area .

The present disclosure also provides a video output method performed by a video output device, in which a brightness value of the first video data is set in the first video data based on a brightness value of the input first video data. In the case of a low brightness area, noise generated in a wide set amplitude range is added, and when the brightness value of the first video data is in a high brightness area, noise is generated in a narrowly set amplitude range. and converting the second video data to which the noise has been added into display video data of a second gradation value that is smaller than the first gradation value obtained from the first video data. and outputting display video data of the second gradation.

The present disclosure also provides a video output system including an imaging device, a video output device capable of communicating with the imaging device, and a display device capable of communicating with the video output device, wherein the imaging device First video data is generated and output to the video output device, and the video output device converts the first video data into the first video data based on the luminance value of the first video data. If the brightness value of the first video data is in a low brightness region, the noise generated in a wide set amplitude range is added, and if the brightness value of the first video data is in a high brightness region, the noise generated in a wide set amplitude range is added. generating second video data to which the noise generated in the amplitude range is added; A video output system is provided in which the data is converted into gradation display video data and outputted to the display device, and the display device displays the output display video data.

According to the present disclosure, when acquiring a video having a relatively high frame rate and transmitting it to a display device, it is possible to suppress a decrease in the quality of the displayed video and an increase in the amount of video transmission and the amount of calculation. .

A block diagram showing a first example of the configuration of a video display system including an imaging device according to the present embodiment A diagram showing an example of noise characteristics in the imaging device according to the present embodiment A diagram showing an operation example of adding noise to video data in the imaging device according to the present embodiment. A block diagram showing a second example of the configuration of a video display system including an imaging device according to the present embodiment FIG. 2 is a diagram illustrating an example of the relationship between the output brightness value of a video signal and a noise level in an imaging device, and is a diagram illustrating a virtual state in which no noise occurs. 2 is a diagram illustrating an example of the relationship between the output brightness value of a video signal and a noise level in an imaging device, and is a diagram illustrating an actual state of an imaging device in which optical shot noise occurs. FIG. Diagram showing an example of operation in an imaging device of a comparative example A diagram showing an example of operation in the imaging device of this embodiment

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, each embodiment specifically disclosing a configuration according to the present disclosure will be described in detail with reference to the drawings as appropriate. However, more detailed explanation than necessary may be omitted. For example, detailed explanations of well-known matters or redundant explanations of substantially the same configurations may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art. The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter recited in the claims.

In this embodiment, a configuration of a video display system that displays video having a relatively high frame rate will be exemplified, and an example of the configuration and operation of an imaging device that acquires and transmits high frame rate video in this video display system will be described. I will explain about it. As a high frame rate video display system, a configuration for displaying a video with a frame rate of 480 fps, for example, is shown. The frame rate used is a value such as 480 fps or 960 fps, which is sufficiently higher than the 30 fps to 60 fps used for normal video. This embodiment shows an example of a configuration in which delay is suppressed by displaying a video at a high frame rate, and an increase in the amount of video transmission and the amount of calculation is suppressed.

Here, the temporal characteristics of the contrast sensitivity function (CSF) of the visual system will be explained. Regarding the temporal frequency of CSF, the temporal frequency at which no flicker is perceived when the contrast of the stimulus is reversed is called the critical fusion frequency (CFF), and CFF is the maximum detectable frequency of the stimulus under a certain contrast. Corresponds to time frequency. The human CFF is said to be about 50 Hz, and 60 to 120 Hz is considered to be the limit at which contrast changes can be detected at the fastest. In this specification, this upper limit perceptible to humans will be referred to as human visual temporal sensitivity (temporal resolution of visual information processing). In the case of high-speed video with a frame rate of 480 fps or higher, which exceeds the visual temporal sensitivity of humans, humans perceive the video as an afterimage across multiple frames.

Considering such human visual characteristics, in this embodiment, random noise is added to video data at a relatively high frame rate captured by an imaging device, and the number of bits of the brightness value is reduced. Transmit with reduced gradation. In this case, while reducing the gradation value of the video data, so-called dither processing is performed by adding random noise and outputting the data. As a result, the amount of video data is reduced, and the gradation components lost due to the reduction of gradation values are restored by the human eye's afterimage perception of multiple frames, giving pseudo gradations. Suppressing the deterioration in quality of displayed images.

It is known that stochastic resonance occurs by adding random noise to a signal. In this embodiment, by using stochastic resonance and intentionally adding random noise to video data to make it possible to detect signal components below a threshold value with a certain probability, the gradation value can be reduced. Recover lost tone components.

Furthermore, in this embodiment, the noise level of random noise added to video data (that is, the amplitude range of addition noise) is adjusted in consideration of optical shot noise as an example of inherent noise generated in an imaging device. In this case, with respect to the noise level of optical shot noise that varies depending on the brightness value of video data, the amplitude range of the addition noise is changed so that the sum of the noise levels is uniform regardless of the brightness value. Details of the addition noise will be described later.

FIG. 1 is a block diagram showing a first example of the configuration of a video display system including an imaging device according to the present embodiment. The video display system 1 includes an imaging device 10 that images an arbitrary object, and a high-speed display device (display device) 30 into which video data (video signal) output from the imaging device 10 is input in real time.

The imaging apparatus 10 includes an imaging device 11 and a video output section 12. The imaging device 10 may be composed of, for example, a one-chip semiconductor device in which the imaging device 11 and the video output section 12 are integrated, or the imaging device 11 and the video output section 12 may be configured separately. For example, the structure may include a plurality of chips of semiconductor devices.

The imaging device 11 includes a solid-state imaging element such as a CCD (Charge Coupled Device) type image sensor or a CMOS (Complementary Metal Oxide Semiconductor) type image sensor. The imaging device 11 captures an image of a subject formed by an imaging lens (not shown), and obtains an imaging signal at a high frame rate of, for example, 480 fps or higher, which exceeds human visual temporal sensitivity. The imaging device 11 then generates first gradation video data (hereinafter also referred to as captured video data) having a first number of bits (for example, 8 bits). The frame rate of the captured video data is, for example, about 1000 fps. The video data of the first gradation has a luminance value of the first gradation (for example, 8 bits). Therefore, the imaging device 11 generates and outputs video data of a total of 24 bits, for example, 8 bits for each color of R, G, and B, for a captured image obtained by photoelectrically converting a subject image. At this time, the imaging device 11 outputs video data of the first gradation with a predetermined gain according to the gain setting value inputted by the user setting or the like.

The video output unit 12 encodes the first gradation video data and generates second gradation video data (hereinafter referred to as display video data) having a second number of bits (for example, 4 bits) smaller than the first number of bits. ) is generated and output. That is, the video output unit 12 generates and outputs display video data of a second gradation value, which is smaller in gradation value than the first gradation value normally obtained from the captured video data. The video output section 12 includes a calculation section 13 , a noise generator 14 , an adder 15 , and a quantizer 16 . Here, the calculation section 13, the noise generator 14, and the adder 15 have a function as an example of a noise adding section, and the quantizer 16 has a function as an example of a modulation section.

Based on the brightness value of the video data output from the imaging device 11, the calculation unit 13 calculates the amplitude range of the addition noise according to the brightness value. At this time, the calculation unit 13 calculates the amplitude range of the addition noise according to the luminance value according to the gain setting value inputted by the user setting or the like. Note that the calculation unit 13 may use the temperature measurement value of the imaging device output from the imaging device 11 to calculate the amplitude range to which a correction value based on temperature is added. The noise generator 14 is configured with, for example, an oscillator that generates a triangular wave or a random number generator that generates random numbers, and generates addition noise having random values that vary within the amplitude range calculated by the calculation unit 13. do. The adder 15 adds the video data of the first gradation regarding the current frame sequentially output from the imaging device 11 and the addition noise output from the noise generator 14, and converts the video data after adding the noise into a quantizer. Output for 16.

The quantizer 16 quantizes the video data of the first gradation to which noise has been added, into video data of the second gradation, and sequentially outputs the quantized video data. The quantizer 16 can generate data (quantized data) with a lower gradation than the output of the imaging device 11. Therefore, the imaging device 10 outputs, as high frame rate video data obtained by imaging, second gradation display video data whose data amount is reduced compared to the first gradation captured video data at the time of imaging.

The high-speed display device 30 includes a display device having a known configuration, such as a liquid crystal display, an organic EL (Electro Luminescence) display, and a plasma display. The high-speed display device 30 receives video data (display video data) transmitted from the imaging device 10 and is capable of displaying high-speed video at a high frame rate (for example, 480 fps or higher) that exceeds human visual temporal sensitivity. At this time, the delay between transmitting the display video data from the imaging device 10 to the high-speed display device 30 and displaying it can be reduced to about 1 ms when the frame rate of the display video data is 1000 fps, for example.

FIG. 2 is a diagram showing an example of noise characteristics in the imaging device according to this embodiment. Here, the amplitude range of addition noise in this embodiment will be explained using FIG. 2. In the imaging device 11 of the imaging apparatus 10, optical shot noise is generated as inherent noise, and the output image signal includes a component of the optical shot noise Ns. Since the optical shot noise Ns is proportional to the square root of the number of photons, the noise level increases as the brightness value increases depending on the brightness value of the imaging signal. Further, in the imaging device 11, thermal noise Nt is generated depending on the ambient temperature. The thermal noise Nt has a noise level that is approximately constant regardless of the brightness value of the imaging signal.

In this embodiment, when adding random noise intentionally to recover gradation components lost due to a reduction in the number of bits of a luminance value, the addition noise is Set the amplitude range Na. That is, the amplitude range Na of the addition noise is set to vary according to the brightness value so that the noise level decreases as the brightness value increases. For example, when a brightness value is represented by 8 bits (0 to 255) and the 8-bit brightness value is quantized to 4 bits, random numbers with a uniform distribution in the amplitude range of 0 to 15 are added as addition noise. At this time, the amplitude range of the addition noise (random number generation range) is changed according to the luminance value. More specifically, addition noise generated in a wide amplitude range is added in a low brightness area, and addition noise generated in a narrow amplitude range is added in a high brightness area. As a result, the total sum of the noise level of each brightness value in the imaging device 10 is made uniform over the entire brightness value, that is, the sum of the noise level is made uniform regardless of the brightness value, and the added noise is not added excessively. Avoid doing too much.

If the frame rate of the video data is low, adding noise will only increase flickering and noise. On the other hand, in the case of a high frame rate that exceeds the human visual temporal sensitivity, multiple frames appear to overlap as afterimages, so by keeping the average value and fluctuation value of the added noise within the specified time with an appropriate amount, For human vision, it is possible to visually increase the gradation in a pseudo manner without perceiving flicker.

The amplitude range Na of the addition noise can be expressed, for example, as in equation (1) below.
Na=Q2-sqrt(y)×Cg+Nt...(1)
Here, Q2 is the quantization range to the second gradation, and is 16 if the second number of bits is 4 bits, for example. y is the brightness value of the captured video data output from the imaging device 11, and for example, when the first number of bits is 8 bits, it takes a value from 0 to 255. sqrt(y) indicates the square root of the brightness value y. Therefore, sqrt(y)×Cg corresponds to the standard deviation of the value proportional to the component of the optical shot noise Ns. Cg is a gain correction value, and a predetermined constant depending on the gain setting value of the imaging device 10 may be used. Since the number of photons corresponding to the brightness value of the output of the imaging device 11 changes depending on the gain setting value, the gain correction value Cg is used to perform correction according to the gain setting value. Nt is the value of thermal noise estimated in the imaging device 11. Note that a predetermined coefficient may be further added as a correction value.

Since the total sum N of the noise level including inherent noise and additive noise in the imaging device 10 is N≈Ns+Na+Nt, the amplitude range Na of the additive noise that varies depending on the luminance value is set as in equation (1) above. By doing so, the total sum N of noise levels can be made uniform regardless of the brightness value. For example, it is possible to determine whether the total noise level is uniform regardless of the brightness value by extracting the relationship between brightness and noise through statistical analysis of video data output from the imaging device 10.

FIG. 3 is a diagram showing an example of the operation of adding noise to video data in the imaging device according to the present embodiment. In FIG. 3, in order to simplify the explanation, a case is illustrated in which the amplitude range of the addition noise is set to a fixed value. In the illustrated example, the luminance value of the video data is set to each gradation value from 0 to 240, the amplitude range of the addition noise is set to 16, and the addition noise is set to a variable value that randomly varies between 0 to 15. The adder 15 adds the luminance value of the video data output from the imaging device 11 and the addition noise output from the noise generator 14, and converts the sequentially integrated integral value into a quantizer as video data after adding noise. Output for 16. The quantizer 16 converts the noise-added video data into second gradation video data and sequentially outputs the video data.

FIG. 4 is a block diagram showing a second example of the configuration of a video display system including the imaging device according to the present embodiment. The video display system 1A includes an imaging device 20 that images an arbitrary object, and a high-speed display device 30 into which video data output from the imaging device 20 is input in real time. The second example is another configuration example including an imaging device 20 configured by an analog circuit instead of the imaging device 10 of the first example. Here, components different from those in the first example will be described, and descriptions of similar components will be omitted as appropriate.

The imaging apparatus 20 includes an imaging device 21 and a video output section 22 having an analog configuration. The imaging device 20 may be composed of, for example, a one-chip semiconductor device in which the imaging device 21 and the video output section 22 are integrated, or the imaging device 21 and the video output section 22 may be configured separately. For example, the structure may include a plurality of chips of semiconductor devices.

The imaging device 21 acquires a high frame rate imaging signal and outputs it as an analog video signal (captured video data). The video output unit 22 modulates the video signal output from the imaging device 21 to produce a second gradation (for example, 8 bits) that is smaller in gradation value than the first gradation (for example, 8 bits) normally obtained from the captured video data at the time of imaging. For example, 4 bits) video data (display video data) is generated and output. The video output section 22 includes a noise generator 23, a variable amplifier (AMP) 24, an summing amplifier circuit 25, and an AD converter (ADC) 26. Here, the noise generator 23, the variable amplifier 24, and the addition amplifier circuit 25 have a function as an example of a noise addition section, and the AD converter 26 has a function as an example of a modulation section.

The noise generator 23 includes, for example, an oscillator that generates a triangular wave or an analog noise generation circuit, and generates and outputs random addition noise of a predetermined level. The variable amplifier 24 takes the brightness value of the video signal output from the imaging device 21 as a control input, takes the addition noise generated by the noise generator 23 as a signal input, and uses a gain changed according to the brightness value to suppress the addition noise. Amplify and output. As a result, the variable amplifier 24 outputs additive noise with an amplitude corresponding to the luminance value. The addition amplifier circuit 25 inputs the video signal (captured video data) output from the imaging device 21 and the addition noise output from the variable amplifier 24, adds (superimposes) the two, amplifies and outputs the result. The AD converter 26 converts the noise-added analog video signal output from the summing amplifier circuit 25 into digital data of a second gradation having a second number of bits (for example, 4 bits), and sequentially displays the digital data as display video data. Output. Thereby, the imaging device 10 outputs second gradation display video data, which is obtained by lowering the gradation to reduce the amount of data compared to the output of the imaging device 21, as the high frame rate video data obtained by imaging. .

Next, an example of the operation of the imaging device according to this embodiment will be described. Here, an example of the gradation and noise level of output display video data with respect to the luminance value of captured video data is shown.

FIG. 5 is a diagram illustrating an example of the relationship between the output luminance value of the video signal and the noise level in the imaging device, and is a diagram illustrating a virtual state in which no noise occurs. The upper part of FIG. 5 shows the statistical average value of the output of display video data with respect to the luminance value of captured video data, and represents the gradation visible to the human eye. The lower part of FIG. 5 shows the statistical average value of the noise level output with respect to the luminance value of the captured video data. When the noise level is 0 over the entire range of brightness values of captured video data, when the first gradation (e.g. 8 bits) video data is encoded into the second gradation (e.g. 4 bits) video data, the output display The gradation of the video data becomes rough. In this case, it is visually recognized as a step-like gradation change in human vision.

FIG. 6 is a diagram illustrating an example of the relationship between the output luminance value of a video signal and a noise level in an imaging device, and is a diagram illustrating an actual state of an imaging device in which optical shot noise occurs. The upper part of FIG. 6 shows the statistical average value of the output of the display video data with respect to the luminance value of the captured video data, and the lower part of FIG. 6 shows the statistical average value of the output of the noise level with respect to the luminance value of the captured video data. It shows. Here, for the sake of clarity, we assume a very noisy situation, and show simulation results in which 10,000 normally distributed noises are generated for each luminance value from 0 to 255. In this case, a component of optical shot noise Ns is added to the captured video data as inherent noise naturally generated in the imaging device. Therefore, when encoding video data from the first gradation to the second gradation, a pseudo gradation is given to human vision due to noise addition, and the gradation component lost due to the reduction in the number of bits is recovered. . The noise level of the optical shot noise Ns increases as the luminance value of the captured video data increases, so that the higher the luminance area is, the smoother the gradation change can be obtained as seen by the human eye.

FIG. 7 is a diagram showing an example of the relationship between the output luminance value of the video signal and the noise value as an operation example of the imaging device of the comparative example. FIG. The upper part of FIG. 7 shows the statistical average value of the output of the display video data with respect to the luminance value of the captured video data, and the lower part of FIG. 7 shows the statistical average value of the output of the noise level with respect to the luminance value of the captured video data. It shows. Here, for the sake of clarity, we assume a very noisy situation, and show simulation results in which 10,000 normally distributed noises are generated for each luminance value from 0 to 255. The comparative example is an example in which addition noise Na is added in a uniform range from low brightness to high brightness. In this comparative example, the total noise level N increases as the luminance value increases in conjunction with the optical shot noise Ns because the addition noise Na is constant. In this case, in the high brightness region, excessive noise is added, and the standard deviation of the noise level increases, resulting in large fluctuations in the output, which may result in the output level not falling within a predetermined range. This causes distortion in the output video and causes flickering. Furthermore, a problem may arise in which gradations cannot be obtained at both ends of the low-luminance region and the high-luminance region. In this way, it may not be possible to stably secure a dynamic range from low to high brightness, which may lead to a decline in the quality of displayed images.

FIG. 8 is a diagram showing an example of the relationship between the output brightness value of the video signal and the noise value as an example of the operation of the imaging device according to the present embodiment, in which addition noise is added by varying the range according to the brightness value. FIG. The upper part of FIG. 8 shows the statistical average value of the output of the display video data with respect to the luminance value of the captured video data, and the lower part of FIG. 8 shows the statistical average value of the output of the noise level with respect to the luminance value of the captured video data. It shows. Here, for the sake of clarity, we assume a very noisy situation, and for each brightness value from 0 to 255, we generate 10,000 pieces of normally distributed noise, and we simulate it so that the variance is proportional to the brightness value. Showing results. In fact, when the object to be imaged is bright, the S/N ratio changes by lowering the gain setting value of the imaging device, and the noise level can be lowered. Therefore, the amplitude range of addition noise is set according to the luminance value, and the amplitude range is corrected according to the gain setting value.

In this embodiment, the addition noise Na is decreased in response to an increase in the light shot noise Ns according to the brightness value, and added to the captured video data so that the total noise level N is uniform for each brightness value. . This makes it possible to suppress an increase in output deviation of video data. In this way, by varying the addition noise Na so that the noise level decreases as the brightness value increases, it is possible to always add appropriate noise regardless of the brightness value, and it is possible to stably and dynamically add noise from low to high brightness. Secure a microwave. As a result, smooth gradation changes can be obtained in the entire luminance value in human vision, and gradation components lost due to reduction in gradation values can be recovered, and deterioration in the quality of displayed images can be suppressed.

As described above, the imaging apparatuses 10 and 20 of the present embodiment include the imaging devices 11 and 21 that acquire captured video data with a high frame rate that exceeds human visual temporal sensitivity through imaging, and It has video output units 12 and 22 that generate and output display video data of a second gradation having a smaller gradation value than the first gradation. The video output units 12 and 22 each include a noise adding unit (calculation unit) that adds addition noise to the captured video data so that the sum of the noise levels of each luminance value is uniform over the entire luminance value of the captured video data. unit 13, noise generator 14, adder 15, or noise generator 23, variable amplifier 24, addition amplifier circuit 25), converts the video data to which addition noise has been added into display video data of the second gradation. A modulation section (quantizer 16 or AD converter 26). In this embodiment, when acquiring high frame rate captured video data and transmitting it to a display device, additive noise is added to the captured video data, and the first gradation is higher than the first gradation normally obtained from the captured video data. Display video data of a second gradation having a small gradation value is generated and output. This kind of signal processing reduces the amount of video data and suppresses delays, while also restoring the gradation components lost due to the reduction of gradation values through the human eye's perception of multiple frames as afterimages. . At this time, by making the sum of the noise levels of each luminance value uniform over the entire luminance value of the captured video data, it is possible to prevent excessive additive noise from being added, and to prevent flickering of the image. can suppress quality deterioration. This makes it possible to suppress an increase in the amount of video transmission and the amount of calculation while suppressing a deterioration in the quality of displayed images.

Furthermore, in the imaging device 10, the video output unit 12 outputs a second bit smaller than the first number of bits based on the captured video data of the first gradation having the first number of bits output from the imaging device 11. second gradation display video data having a number of numbers is generated and output. This makes it possible to reduce the amount of data and suppress delays by reducing the number of bits of the luminance value of video data.

In the imaging device 10, the video output unit 12 also includes, as a noise addition unit, a calculation unit 13 that calculates the amplitude range of addition noise according to the luminance value of the captured video data of the first gradation, and The noise generator 14 includes a noise generator 14 that outputs random noise as addition noise, and an adder 15 that adds the captured video data and the addition noise. Further, the video output unit 12, as a modulation unit, quantizes the video data to which addition noise has been added to the captured video data of the first gradation, into video data of the second gradation, and sequentially outputs the quantized video data as display video data. A quantizer 16 is included. As a result, noise is intentionally added to the captured video signal using a configuration that performs digital signal processing, and the gradation components lost due to the reduction in gradation values are recovered, and the amount of video data is reduced. This makes it possible to suppress delays.

In addition, in the imaging device 20, the video output unit 22 functions as a noise addition unit, and adds random noise generated by a noise generator 23 or the like in the device to a luminance value of the captured video data output from the imaging device 21. It includes a variable amplifier 24 that amplifies the amplitude and outputs it as addition noise, and an addition amplification circuit 25 that superimposes the captured video data output from the imaging device 21 and the addition noise and outputs the superimposed image data. The video output section 22 also serves as a modulation section and converts the noise-added analog video signal outputted from the summing amplifier circuit 25 into digital data of a second gradation, and sequentially outputs the digital data as display video data. Contains 26. As a result, by using a configuration that performs analog signal processing, noise is intentionally added to the captured video signal, recovering the gradation components lost due to the reduction of gradation values, and reducing the amount of video data. This makes it possible to suppress delays.

Further, in the imaging devices 10 and 20, video data with a frame rate of 480 fps or more is acquired as high frame rate captured video data. In this way, when performing high-speed video display using video data with a high frame rate of 480 fps or higher, it is possible to suppress the increase in the amount of video transmission and the amount of calculation while suppressing the deterioration in the quality of the displayed video. It becomes possible.

In addition, in the imaging devices 10 and 20, the noise addition units of the video output units 12 and 22 reduce and add added noise as the luminance value of the captured video data increases, and add noise that is unique to the imaging devices 11 and 21. The sum of the noise levels including the noise and the addition noise is uniform over the entire brightness value of the captured video data. As a result, it is possible to make the sum of the noise levels of each brightness value uniform over the entire brightness value of the captured video data, and to prevent adding too much noise, especially in high brightness areas, and to improve the image quality. Quality deterioration such as flickering can be suppressed.

The video output method of the present embodiment includes the steps of acquiring captured video data captured by the imaging devices 11 and 21 at a high frame rate that exceeds human visual temporal sensitivity, and The step of adding additive noise to the captured video data so that the sum of the noise levels of the values is uniform, and using the video data after adding the additive noise, the first The present invention includes a step of generating display video data of a second gradation having a gradation value smaller than the gradation, and a step of outputting display video data of the second gradation to the high-speed display device 30. As a result, when acquiring video with a relatively high frame rate and transmitting it to a display device, it is possible to suppress a decrease in the quality of the displayed video and an increase in the amount of video transmission and calculation amount. become.

Although various embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to such examples. It is clear that those skilled in the art can come up with various changes or modifications within the scope of the claims, and these naturally fall within the technical scope of the present invention. Understood. Further, each component in the above embodiments may be arbitrarily combined without departing from the spirit of the invention.

The present disclosure makes it possible to suppress an increase in the amount of video transmission and the amount of calculation while suppressing a deterioration in the quality of the displayed image when acquiring a video having a relatively high frame rate and transmitting it to a display device. The present invention is useful as a video output device, a video output method, and a video output system.

1, 1A Video display system 10, 20 Imaging device 11, 21 Imaging device 12, 22 Video output section 13 Arithmetic section 14 Noise generator 15 Adder 16 Quantizer 23 Noise generator 24 Variable amplifier 25 Summing amplifier circuit 26 AD converter 30 High-speed display device

Claims (6)

a noise adding unit that adds noise to the first video data based on the luminance value of the input first video data;
a modulation unit that converts the second video data to which the noise is added into display video data of a second gradation having a smaller gradation value than the first gradation obtained from the first video data;
a video output unit that outputs the display video data of the second gradation ;
When the brightness value of the first video data is in a low brightness region, the noise adding section adds the noise generated in a wide set amplitude range, so that the brightness value of the first video data is In the case of a high brightness area, adding the noise generated in a narrowly set amplitude range ;
Video output device. The modulation unit includes a quantizer that quantizes the second video data into video data of the second gradation and sequentially outputs the quantized video data as the display video data.
The video output device according to claim 1. The first video data is video data with a frame rate of 480 fps or more,
The video output device according to claim 1. The sum of the noise levels including the noise and inherent noise generated in the device that generates the first video data is uniform over the entire brightness value of the second video data.
The video output device according to claim 1. A video output method performed by a video output device, comprising:
Based on the brightness value of the input first video data, if the brightness value of the first video data is in a low brightness region, the first video data is generated in a wide set amplitude range. adding noise, and when the luminance value of the first video data is in a high luminance region, adding the noise generated in a narrowly set amplitude range;
converting the second video data to which the noise has been added into display video data of a second gradation having a smaller gradation value than the first gradation obtained from the first video data;
outputting the display video data of the second gradation;
Video output method. an imaging device;
a video output device capable of communicating with the imaging device;
A video output system comprising: a display device capable of communicating with the video output device,
The imaging device includes:
generating first video data by imaging and outputting it to the video output device;
The video output device includes:
Based on the brightness value of the first video data, if the brightness value of the first video data is in a low brightness region, noise generated in a wide set amplitude range is added to the first video data. and when the brightness value of the first video data is in a high brightness region, generating second video data to which the noise generated in a narrowly set amplitude range is added;
converting the second video data into display video data of a second gradation having a smaller gradation value than the first gradation obtained from the first video data, and outputting it to the display device;
The display device includes:
displaying the outputted display video data;
Video output system.