JPH04304081A - Picture signal converting device - Google Patents

Abstract

PURPOSE:To much facilitate the gamma correction by performing the gamma correction separately in accordance with a video camera and film. CONSTITUTION:The video recording is performed for a picture signal VD 11 of a video camera 21 by a digital VTR 22 and picture information VD12 is obtained by converting the picture signal into a low speed picture in a VTR23 for low speed reproduction. The information for recording for a frame of the low speed reproduction picture is prepared in an input circuit 25 of a next picture signal converting circuit part 24 and is divided into the three-component of RGB. A linearizer 26 performs the correction for the obtained converted picture information VD13 by multiplying the inverse characteristic of camera gamma characteristic. The color correction is performed for corrected information VD14 in a color correction circuit 28 so that the information may be fitted to color reproducibility characteristic. A correction gamma circuit 31 for film prepares the color corrected information VD15, VD16 based on the optimum correction characteristic and outputs film recording information VD18 via a frame memory 32 and a buffer 33. The information is monitored by a monitor circuit 35 and is supplied to an EBR unit 15 via a D/A converter. The gamma correction becomes easy as the information for gamma correction is independently selected.

Description

[Detailed description of the invention]

0001

[Table of Contents] The present invention will be explained in the following order. Industrial applications Conventional technology (Figures 8 and 9) Problems to be solved by the invention (Figure 8) Means to solve problems (Figure 1) Effect (Figure 1) Examples (Figures 1 to 7) Effect of the invention

0002

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image signal converting apparatus, and is suitable for application, for example, to forming an image captured by a video camera on a motion picture film.

0003

2. Description of the Related Art Conventionally, an image signal converter (EBR (electron beam
recorder) ).

That is, as shown in FIG. 8, an image signal conversion device 1 converts a video image signal V obtained from a video camera 2 into
After D1 is once recorded on the recording VTR 3, it is played back at low speed using the subsequent low speed playback VTR 4 and inputted to the EBR device 5.

[0005] The EBR device 5 receives a video image signal V consisting of a low-speed reproduced image inputted in the image signal conversion circuit section 6.
A film recording signal VD is obtained by sequentially and intermittently outputting one frame of image data for each red component, green component, and blue component by performing predetermined signal processing on D2.
3, followed by beam gun 8 of EBR unit 15.
Enter.

The beam gun 8 scans the electron beam BM on the monochrome film 9 and modulates the intensity of the electron beam BM according to the input film recording signal VD3, thereby adjusting the contrast of the color image based on the film recording signal VD3. Only the black and white images are formed on the black and white film 9.

Here, the image formed on the black-and-white film 9 is divided into red components, green components, and blue components of one frame image intermittently output from the image signal conversion circuit section 6, as shown in FIG. Each frame is allocated sequentially.

That is, when the EBR unit 15 records the contrast of the red component of the film recording signal VD3 in the first recording area of the black-and-white film 9 to form a contrast image FR1 of the red component, the EBR unit 15 records the contrast of the red component of the film recording signal VD3 in the first recording area of the black-and-white film 9 to form a contrast image FR1 of the red component. The black-and-white film 9 is advanced by one frame and then stopped, and the contrast of the green component of the recording signal VD3 is recorded in the subsequent second recording area to form a contrast image FG1 of the green component, and the black-and-white film 9 is further advanced by one frame and then stopped. Then, the contrast of the blue component of the recording signal VD3 is recorded in the subsequent third recording area to form a blue component image FB1.

In this way, on the black and white film 9, the red component of the reproduced image output from the low-speed reproduction VTR 4,
Contrast images FR1 and F of green and blue components
G1 and FB1 are sequentially formed in that order.

Further, the contrast images FR1, FG1 and FB1 of the respective primary color components formed on the black and white film 9 are obtained by passing the contrast image FR1 of the red component through a red filter R of a filter 10 to the first color negative film 11.
At the same time, the contrast image FG1 of the green component is recorded in the first recording area of the color negative film 11 through the green filter G of the filter 10, and the contrast image FB1 of the blue component is recorded in the first recording area of the color negative film 11 through the green filter G of the filter 10.
A color negative image FCOLN is formed in the first recording area of the color negative film 11 by combining the red component, the green component, and the blue component. be done.

Furthermore, by transferring the image on the color negative film 11 to a color positive film 12, this can be used as a movie film.

0012

[Problems to be Solved by the Invention] By the way, the video image signal VD1 output from the video camera 2 is
In order to obtain a natural image even when input to an RT (cathode ray tube), the input image captured by the video camera 2 is corrected according to the gamma characteristics of the phosphor of the CRT (this is called the camera gamma characteristic). Image and video camera 2
The relationship between the output images output from is not a linear relationship.

Further, in the image signal conversion device 1 using the EBR device, a film recording signal V consisting of an electric signal is
When recording D1 on a film, it is necessary to make corrections in accordance with the gamma characteristics of the film.

Therefore, in the image signal conversion circuit section 6, gamma correction is performed to match the video image signal VD2 to the gamma characteristics of the film.

0015
] This gamma correction is designed to simultaneously correct the camera gamma characteristics and correct the gamma characteristics of the film. One correction curve includes the correction characteristics based on the camera gamma characteristics and the correction characteristics based on the film gamma characteristics. It is necessary to have them at the same time.

However, when attempting to correct the camera gamma characteristics and the film gamma characteristics at the same time as described above, it becomes complicated to determine the correction characteristics that match the camera gamma characteristics and the film gamma characteristics, and it is necessary to correct either the video camera or the film. Just by changing the camera, the correction characteristics had to be set again, and there were restrictions on the selection of video cameras and films.

The present invention has been made in consideration of the above points, and it is an object of the present invention to propose an image signal conversion device that can more easily perform gamma correction.

[0018]

[Means for Solving the Problems] In order to solve the above problems, the present invention provides an image signal conversion device 20 for converting an image signal VD11 obtained from the video camera 21 into a film recording signal VD18. The first correcting means 26 corrects the gamma characteristic of the image signal VD11 to be processed, and the second correcting means 31 corrects the gamma characteristic of the image signal VD15 according to the gamma characteristics of the films 9, 11, and 12. Gamma correction by the correction means 26 and the second correction means 31 is performed independently.

[0019]

[Operation] Video camera 21 and films 9, 11, 12
By performing gamma correction separately depending on the video camera 21 and films 9, 11, and 12, it is possible to independently select data for gamma correction for each of the video cameras 21 and films 9, 11, and 12. Gamma correction can be performed more easily depending on the film.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, in which parts corresponding to those in FIG. 8 are denoted by the same reference numerals, the image signal conversion device 20 is
EBR is designed to form images on movie film from high-quality digital video images captured in 1.
After the video image signal VD11 obtained from the video camera 21 is once recorded in the recording digital VTR 22, the normal video signal consisting of 30 consecutive frames of video data per second is recorded in the subsequent low-speed playback digital VTR 23. VD11 to black and white film 9 (
Video image data VD12 is obtained by converting into a 1/30 low-speed image according to the characteristics shown in FIG. 9).

This conversion rate (1/30) means that the time to which a signal for one frame of the video signal VD11 is allocated is used to convert the image for one frame of the video signal VD11 into E.
It is divided by the recording time on the black and white film 9 in the BR unit 15.

As shown in FIG. 2, this video image data VD12 is converted into such a low-speed image as shown in FIG.
The same one frame image is repeated 30 times per second, and the first 15 repeated images are assigned to the odd field of the slow playback image, and the latter 15 repeated images are assigned to the slow playback image. By assigning to even fields, one frame of still images is formed per second.

[0024] Accordingly, by sequentially switching the repeated images forming the still image every second, a low-speed reproduction image in which the scene progresses every second is obtained.

Video image data V configured in this manner
D12 is the input circuit 25 of the subsequent image signal conversion circuit section 24.
and the odd field (odd
Sample frame SF
1, and even field (even
Sample frame SF
2 and the corresponding sample frames SF1 and S
Image data for film recording corresponding to one frame of the low-speed reproduction image is created by F2.

The input circuit 25 also transmits the clock frequency (74.25 MHz in this embodiment) transmitting the video image data VD12 to the image conversion circuit section 24.
The frequency is lowered to a predetermined frequency in accordance with the TTL/MOS hardware that constitutes the data, and the data is divided into red component data VDR, green component data VDG, and blue component data VDB in a predetermined digital matrix circuit.

The converted image data V thus obtained
D13 is input to the subsequent linearizer 26, and the gamma characteristics of the image data corrected by the video camera 21 are restored to the original characteristics.

In other words, the linearizer 26 multiplies the input converted image data VD13 by the inverse characteristic of the camera gamma characteristic in the video camera 21, so as to return it to image data corresponding to the image originally input to the video camera 21. being done.

This reverse characteristic is achieved by a ROM (read only memory) provided inside the linearizer 26.
y), various data are stored at each address for each type of video camera to be used, and data corresponding to the video camera 21 is read out.

The image data VD14 thus corrected based on the camera gamma characteristics of the video camera 21 is input to the subsequent color correction circuit 28.

Since the camera gamma characteristics of the image data VD14 inputted at this time have been corrected, the color correction circuit 28 pays attention only to the characteristics of the film, and adjusts red to match the color reproduction characteristics of the film. Color correction is performed by performing numerical calculations between the green component and the blue component.

Furthermore, when the color correction circuit 28 corrects the image data according to the gamma characteristics of the film in the subsequent film gamma correction circuit 31, the red component, green component, and blue component of the image data are changed. These color components are corrected in advance in anticipation of the possibility that the image will be distorted.

That is, as shown in FIG.
is composed of a red component correction circuit section 28R that corrects the red component data VDR, a green component correction circuit section 28G that corrects the green component data VDG, and a blue component correction circuit section 28B that corrects the blue component data VDB. The component correction circuit section 28R inputs 12 bits of data forming the red component data VDR out of the image data VD14 input to the color correction circuit 28 to the arithmetic circuit 28RC, and also inputs the data of the red component data VDR to the calculation circuit 28RC. Among them, the upper 8 bits of data are input to the color determination circuit 28RA.

At the same time, the color determination circuit 28RA
Of the image data VD14 input to the color correction circuit 28, the upper 3 [bits] of the green component data VDG and the upper 3 [bits] of the blue component data VDB are
] Enter the data.

[0035] Here, each color component data is designed to represent the brightness, saturation, and hue of the color represented by the data in more detail from the upper bit to the lower bit constituting the data, and the color judgment circuit 28RA The colors of the input red component data are grouped based on the green component and the blue component.

Color groups include, for example, achromatic colors, monochromatic colors,
A correction data generation circuit 28 which is divided into intermediate color, skin color, etc., further determines the degree, and continues with the determination information DR1.
Input to RB.

The correction data generation circuit 28RB outputs the red correction data DR2 based on the input judgment information DR1, and adds (or multiplies) it to the red component data VDR in the arithmetic circuit 28RC.

In the case of this embodiment, correction data is generated by focusing on the fact that the saturation and brightness of the image data corrected by the subsequent film gamma correction circuit 31 decreases as it becomes a single color of red, green, or blue. When the color represented by the image data VD14 in the determination circuit 28RA is a single red color, the circuit 28RB outputs the red correction data DR2, thereby adjusting the red component data VDR.
The correction is made to increase the saturation and brightness level of the image.

On the other hand, the green component correction circuit section 28G extracts 12 [bits] of the image data VD14 inputted to the color correction circuit 28, which constitutes the green component data VDG.
of the green component data VDG is input to the arithmetic circuit 28GC, and data for the upper 8 [bits] of the green component data VDG is input to the color determination circuit 28GA.

At the same time, the color determination circuit 28GA
Of the image data VD14 input to the color correction circuit 28, the upper 3 [bits] of the red component data VDR and the upper 3 [bits] of the blue component data VDB are
] Enter the data.

The color determination circuit 28RA classifies the input green component data into groups based on the red component and the blue component.

Color groups include, for example, achromatic colors, monochromatic colors,
A correction data generation circuit 28 which is divided into intermediate color, skin color, etc., further determines the degree, and continues with the determination information DG1.
It is input to GB.

The correction data generation circuit 28GB outputs green correction data DG2 based on the input determination information DG1, and adds (or multiplies) it to the green component data VDG in the arithmetic circuit 28GC.

Here, when the color represented by the image data VD14 in the determination circuit 28GA is a single green color, the correction data generation circuit 28GB outputs the green correction data DG2, thereby generating the green component data VD.
Correction is made to increase the saturation and brightness level of G.

On the other hand, the blue component correction circuit section 28B extracts 12 [bits] of the image data VD14 inputted to the color correction circuit 28, which constitutes the blue component data VDB.
of the blue component data VDB is input to the arithmetic circuit 28BC, and data of the upper 8 [bits] of the blue component data VDB is input to the color determination circuit 28BA.

At the same time, the color determination circuit 28BA
Of the image data VD14 input to the color correction circuit 28, the upper 3 [bits] of the red component data VDR and the upper 3 [bits] of the green component data VDG are
] Enter the data.

The color determination circuit 28GA classifies the input blue component data into groups based on the red component and the green component.

Color groups include, for example, achromatic colors, single colors,
A correction data generation circuit 28 which is divided into neutral color, skin color, etc., further determines its degree, and continues with the relevant determination information DB1.
Input to BB.

The correction data generation circuit 28BB outputs blue correction data DB2 based on the input judgment information DB1, and adds (or multiplies) it to the green component data VDB in the arithmetic circuit 28BC.

Here, when the color represented by the image data VD14 in the determination circuit 28BA is a single blue color, the correction data generation circuit 28BB outputs the blue correction data DB2, thereby generating the blue component data VD.
Correction is made to increase the saturation and brightness level of B.

In this way, the image data VD15 outputted from the color correction circuit 28 is corrected in advance for changing color components in the film gamma correction circuit 31 at the subsequent stage.

The film gamma correction circuit 31 is a circuit that corrects image data in accordance with the density characteristics of the film, and the film recording data VD18 obtained as an output signal of the image signal conversion circuit section 24 is sent to the EBR unit 15.
When the intensity of the electron beam BM is modulated in the method, correct density changes are caused on the film.

The correction characteristic curve used in this film gamma correction circuit 31 is based on the film used,
The most suitable one is selected depending on the cut of the video and the scene of the video.

Therefore, the gamma correction circuit 31 for the film concerned
RAM (random access memo)
ry) configuration conversion table is used, and the corresponding R
A computer for inputting AM allows various correction characteristic curves to be set in accordance with the conditions of the film and the like.

In the case of this embodiment, focusing on the fact that the dynamic range from the black level to the white level in the video image captured by the video camera 21 is narrower than that of the film, FIG. Input image data VD is determined by correction characteristic curves (red correction curve R, green correction curve G, blue correction curve B) as shown in 4.
Corrections that apparently widen the dynamic range of 15 gradations on the black level side and the white level side are performed on the red component data VDR, the green component data VDG, and the blue component data VDB, respectively.

The image data VD16 thus corrected according to the gamma characteristics of the film is temporarily stored in the frame memory 32.
The electron beam BM (
By sequentially and intermittently reading out the red component data VDR, green component data VDG, and blue component data VDB for each frame at a timing and clock rate corresponding to the deflection and film frame advance operation shown in FIG. 8), the data shown in FIG. 5 is obtained. Film recording data VD18 is obtained as follows.

In this embodiment, the red component data VDR, green component data VDG, and blue component data V of one frame of image data FRAME1, FRAME2, .
The time TOUT1 for forming an image on the recording area of three frames on the film 9 for each DB is 1 second, and the corresponding 1
Red component data VDR, green component data VDG, and blue component data VDB are sequentially and intermittently output per second.

Therefore, the red component data VDR, the green component data VDG, and the blue component data VDB are each about 0.
．． It is 15 seconds long and is output at approximately 0.15 second intervals.

The film recording data VD18 is thus sent to the EBR unit 15 via the digital-to-analog conversion circuit 34, and contrast images FR1, FG1, and FB1 (FIG. 9) of each primary color component are formed on the black-and-white film 9 (FIG. 8).
form.

At the same time, the buffer circuit 33 inputs the film recording data VD18 to the monitor circuit 35, and produces an image equivalent to the composite image of the contrast images FR1, FG1, and FB1 of each primary color component formed on the black and white film 9. It is designed to convert the signal into a signal that can be monitored.

That is, as shown in FIG.
5 inputs film recording data VD18 to an input circuit 41 and a memory control circuit 42.

The input circuit 42 performs serial/parallel conversion on the film recording signal data 18, which is a digital signal, and lowers the clock frequency to a level that can handle the TTL/CMOS elements constituting the monitor circuit 35.

In this example, 59.4 [MHz]
Approximately 15 [M
Hz], and then sent to the first frame memory 43 or the second frame memory 44.

The memory control circuit 42 also includes a transmission clock used for serial/parallel conversion from the clock of the film recording data VD18, a write clock for storing the film recording data VD18 in the frame memories 43 and 44, and a clock for storing the film recording data VD18 in the frame memories 43 and 44. A read clock for reading out data stored in the frame memories 43 and 44, a switching signal for switching between the frame memories 43 and 44, a clock for executing parallel/serial conversion in the output circuit 45, etc. are output as the control signal SCON. There is.

Here, the frame memory 43 stores the three primary color signals V transmitted as the film recording signal VD18.
The frame memory 44 is composed of three frame memories configured to store DR, VDG, and VDB, respectively, and the frame memory 44 is also composed of three frame memories configured to store three primary color signals VDR, VDG, and VDB, respectively. Become.

The frame memories 43 and 44 are configured to alternately store the film recording data VD18 for each frame based on the control signal SCON outputted from the memory control circuit 42.

That is, as shown in FIG. 7, three primary color signals VD(
Rx), VD(Gx) and VD(Bx) (VDR in Figure 5
, VDG, and VDB).
7 (B)), 43G (Fig. 7 (C)) and 43B (Fig. 7
(D)) is controlled to the write mode state by the control signal SCON between time t1 and t2, and the input primary color signals VD(R1), VD
(G1) and VD (B1) are respectively stored sequentially.

Furthermore, when all of the primary color signals VD(R1), VD(G1), and VD(B1) for one frame are stored at time t2, the frame memories 43R, 43G, and 43B are respectively controlled by the control signal SCON. The output circuit 45 is controlled to read mode state, and at this time, the output circuit 45 outputs each primary color signal VD (R1), VD (G1), VD for one frame stored in the frame memories 43R, 43G, and 43B.
(B1) to 1/3 each based on the control signal SCON.
Read repeatedly at a speed of 0 seconds.

Furthermore, the three frame memories 44R (FIG. 7(E)) and 44G (FIG. 7(F)) of the second frame memory 44
)) and 44B (FIG. 7(G)) control signal SCON at time t3 to t4 while the first frame memories 43R, 43G, and 43B are in the read mode state.
The primary color signals VD (R1), VD (G1), VD (B
Each primary color signal V of the second frame input following 1)
D(R2), VD(G2), and VD(B2) are each stored sequentially.

Further, when all of the primary color signals VD (R2), VD (G2) and VD (B2) for one frame are stored at time t4, the corresponding frame memories 44R and 44G
and 44B are each controlled to the read mode state by the control signal SCON, and at this time, the output circuit 45 outputs each primary color signal VD (R2), VD (G2) for one frame stored in the frame memories 44R, 44G, and 44B. and VD (B2) are each set to 1 based on the control signal SCON.
It is read out repeatedly at a speed of /30 [seconds].

Furthermore, the frame memories 44R and 44G
and 44B is controlled to the read mode state, from time 5 to t6, the first frame memory 43R
, 43G and 43B are each controlled to write mode by the control signal SCON, and the respective primary color signals VD(R2), VD(G2) and VD(B2) of the second frame
Each primary color signal VD(
R3), VD (G3) and VD (B3) are stored in sequence.

In this way, the first and second frame memories 43 (43R, 43G, 43B) and 44 (44R
, 44G, 44B) are alternately controlled to write mode state and read mode state, respectively, and are sequentially input primary color signals VD(R1), VD(G1).
, VD (B1) and VD (R2), VD (G2), VD
(B2) and VD (R3), VD (G3), VD (B3
)... are stored alternately for one frame each, and the stored primary color signals VD (R1), V
D (G1), VD (B1) and VD (R2), VD (G
2), VD (B2) and VD (R3), VD (G3),
VD (B3)... are repeatedly read out at a speed of 1/30 [second], parallel/serial conversion is performed in the output circuit 45, and digital-to-analog conversion is performed to convert the normal video signal frequency (i.e., low-speed A monitor image signal VD19 consisting of the frequency of the video image data VD12 forming the reproduced image is obtained.

Therefore, the monitor image signal VD19 is CR
This can be displayed as an image by inputting it to T36.

Here, the memory control circuit 42 receives the primary color signal VD (R1) for one frame of the film recording data VD18.
), VD (G1), and VD (B1) are frame memory 43
When the time point t2 is reached when all the signals are stored in the frame memory 43, the primary color signals VD(R1) and VD(G1)
, VD (B1), and one frame of primary color signals VD (R2), VD of the film recording signal VD18.
(G2), VD (B2) are all stored in the frame memory 44, the switch is then switched to the frame memory 44 side, and the primary color signals VD (R2), VD (G2) are stored in the frame memory 44.
), VD (B2), the monitor image signal VD19 becomes the primary color signal VD (R1) of the film recording data VD18 for one frame at time t2 to t4 (approximately 1 second). ,V
A composite color image signal based on D(G1) and VD(B1) is repeatedly formed, and primary color signals VD(R2) and VD( G2), VD(B2
) is repeatedly formed.

Therefore, on the display screen of the CRT 36,
At time points t2 to t4, primary color signals VD(R1), VD(G1), for one frame of film recording data VD18,
The composite color image of VD(B1) is displayed as a still image, and at the time t4 to t6, the primary color signal VD(B1) is displayed as a still image.
A composite color image of R2), VD (G2), and VD (B2) is displayed as a still image, and thereafter the film recording data V
Each time the D18 image for one frame is stored in the frame memory 43 or 44, the still image for one frame is sequentially displayed, thereby obtaining a low-speed reproduction image in which the scene progresses every second.

The timing at which the frame memories 43 and 44 are switched is set within the film feeding time during which the black and white film 9 is fed frame by frame, and further during the vertical blanking period of the monitor image signal VD19. By this, the first frame memory 43 and the second frame memory 43
The image signals alternately output from the frame memory 44 can be smoothly combined.

Further, the monitor image signal VD19 is film recording data VD18 recorded on the black and white film 9.
The film recording signal data 18 actually recorded on the black and white film 9 (FIG. 9) can be displayed in real time on the CRT 36 by being inputted to the CRT 36 in synchronization with the above.

In the above configuration, the image signal conversion device 2
0 is used to restore the gamma characteristics of the image data corrected by the video camera 21 to the original characteristics by the linearizer 26, and to adjust the gamma characteristics of the film to be used by the film gamma correction circuit 31. By correcting the image data according to the characteristics, it is possible to separately correct only the film gamma characteristics without considering the camera gamma characteristics.

Therefore, when the video camera 21 is changed, the correction characteristics of the linearizer 26 must be changed accordingly, and when the film is changed, the correction characteristics of the film gamma correction circuit 31 must be changed accordingly. Accordingly, it is possible to easily set optimal correction conditions according to the video camera 21 and the film.

According to the above configuration, by performing gamma correction separately for the video camera 21 and the film, it is possible to independently select data for setting conditions for the video camera 21 and the film. Even when either the video camera 21 or the film is changed, it is only necessary to perform gamma correction on the changed side, thereby further improving the work efficiency of gamma correction.

Therefore, the degree of freedom in selecting the video camera 21 and the film can be further improved.

Incidentally, since the image data including the camera gamma characteristics is corrected in advance by the linearizer 26, the color correction circuit 28 adjusts the film characteristics without considering the influence of the camera gamma characteristics. You can make color corrections based solely on

In the above-described embodiment, a case was described in which a correction characteristic curve as shown in FIG. 4 was used in the gamma correction circuit 31, but the present invention is not limited to this. can be set,
Furthermore, various correction characteristic curves can be intentionally set.

Further, in the above embodiment, an EBR apparatus was described that forms an image on a motion picture film from a high-quality digital video image signal, but the present invention is not limited to this, and the present invention is not limited to this. It can be widely applied when converting to

[0085]

As described above, according to the present invention, gamma correction is performed separately for the video camera and the film, so that the gamma correction data for the video camera and the film can be independently processed. This makes it possible to realize an image signal conversion device that can more easily perform gamma correction.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of an image signal conversion device according to the present invention.

FIG. 2 is a schematic diagram showing low-speed image data.

FIG. 3 is a block diagram showing the configuration of a color correction circuit.

FIG. 4 is a characteristic curve diagram showing a gamma correction curve in a gamma correction circuit.

FIG. 5 is a schematic diagram showing film recording data.

FIG. 6 is a block diagram showing the configuration of a monitor circuit.

FIG. 7 is a signal waveform diagram for explaining the operation of the monitor circuit.

FIG. 8 is a block diagram showing a conventional image signal conversion device.

FIG. 9 is a schematic diagram for explaining the process of converting an image onto a film.

[Explanation of symbols]

1, 20... Image signal conversion device, 9... Black and white film,
11... Color negative film, 12... Color positive film, 15... EBR unit, 23... Digital VTR for low speed playback, 24... Image signal conversion circuit section, 25.
41...Input circuit, 26...Linearizer, 28...Color correction circuit, 31...Gamma correction circuit, 32, 43, 44
...Frame memory, 35...Monitor circuit, 36...C
RT, 42...Memory control circuit.

Claims (1)

[Claims] 1. An image signal conversion device for converting an image signal obtained from a video camera into a film recording signal, comprising:
a first correction means for correcting gamma characteristics of the image signal obtained from the video camera; and a second correction means for gamma correction the image signal according to the gamma characteristics of the film; An image signal conversion device characterized in that gamma correction by the correction means and the second correction means is performed independently.