JPS59139024A - Device for photographing crt image on film - Google Patents

Abstract

PURPOSE:To enable automatic correction of non-linearity and decreased luminance by applying signals to an exposing control circuit in a way as to control the duration of an exposing time so as to compensate the decreased luminance on a film. CONSTITUTION:The position signals x, y inputted to the device are applied through adders 30 and 40 to deflecting coils 12 and 13 of a CRT10 and at the same time to sample holding circuit 50a, 50b, and are held by an exposing signal Z. A/D conversion circuits 60a, 60b convert the signals x, y, which are energized by the luminance signal Z' delayed by a time t in a monostable multi 90 and are held in 50a, 50b, to digital signals, and applies said signals as address signals to a storage circuit 70. The circuit 70 tabulates the data signals to be applied to the adders 30, 40 and an exposure control circuit 20, stores the same in the addresses corresponding to the signals x, y, and applies the necessary data to the adders 30, 40 and the circuit 20 according to the addresses. As a result, the non-linearity and the decreased luminance are automatically controlled.

Description

Detailed Description of the Invention The present invention relates to a cathode ray display tube (hereinafter referred to as CRT) that captures a displayed image on a film surface through a lens.
The present invention relates to an image film photographing device.

Conventionally, in this type of photographic device, as the distance R from the center position 0 (located on the central axis of the optical system) of the flat photographic film F increases as shown in FIG. The position shifts non-linearly at a rate as shown in FIG. 2(a), and the brightness decreases non-linearly as shown in FIG. 2(b).

When the size of the photographic film F is small (for example, six-cut size), such distortion and brightness of the photographed image (
The reduction in density is not considered a major problem due to the characteristics, but when shooting on many types of large film sizes (for example, 64 format), the distortion and reduction in density cannot be ignored and correction is necessary. It becomes.

Generally, CT (Computerize) using radiation
In film imaging equipment for γ-ray CT, etc., the linearity of the image described above is less than 0.5% of the effective diameter, and the uniformity of brightness is less than 1%. requested.

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a CRT image film photographing device that can obtain a film plane with non-linearity and brightness reduction corrected through a simple configuration.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings. FIG. 6 is an embodiment diagram of the present invention. In the figure, 10
is a CRT, and the image on its display surface is formed on a film F via a lens L. In this case, C
The distance from the R1 screen to the lens and to the film plane is fixed.

20 is an exposure control circuit that corrects and amplifies the luminance signal 2 as specified, and this output signal is CR, T 1
0 grid 11 as a brightness modulation signal◎
30 and 4o are adders, and each output is X of the CRT.
axial and Y-axis deflection coils 12 and 13. 5
Sample and hold circuits 0a and 50b sample and hold input position signals x and y, and buttons are arranged so that their outputs are fed to a storage circuit 7oK via analog-to-digital converters 60a and 60b. lThis memory circuit 7
o is associated with the position signals x, y K, adder 30.4
For 0, a correction signal is sent to the exposure control circuit 2.
For 0, signals necessary for exposure control are sent. The signals to the adders 30, 40 are provided via digital to analog converters 80a, 80b. 9o is a mono multivibrator, and brightness signal 2
is output after a predetermined time delay and is applied as an energizing signal to the analog/digital converters 60a, 60bK. The operation in such a configuration will be explained as follows. The input position signals x and y are amplified through adders 3o and 4° and applied to the deflection coils 12 and 13 of the CRT 10, as well as to sample and hold circuits 50a and 50b', where they are held as the light passing signal 2. Ru. Analog-digital converter 60a, 6
0b is a position signal generator energized by a luminance signal zIK delayed by one hour by a mono multivibrator 9o and held at 50a50b, as shown in FIG.
to a digital signal. The delay time t is provided to ensure that the output of the sample and hold circuit is sufficiently stabilized before it is converted into digital data. The digital signal is applied to the storage circuit 70 as an address signal. This storage circuit 70 stores data signals to be given to the adder 30.40 and the exposure control circuit 20 in a table form at addresses corresponding to the position signals The data is given to the control circuit 20.

The signal given to the exposure control circuit 20 controls the length of the exposure time so as to compensate for the reduction in brightness on the film F, and it is possible to obtain a photographed image in which the reduction in brightness is automatically corrected.

Note that the memory circuit is a ROM (read only me).
It is preferable that the correction amount for each film size be stored in each ROM, and the corresponding ROM may be selected based on the film size signal obtained from the film cassette.

As described above, according to the present invention, it is possible to realize a CRT image film photographing apparatus that can obtain photographed images with nonlinearity and brightness reduction corrected regardless of the film size, with a simple configuration.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the film plane, FIG. 2 is a diagram showing the linearity and brightness characteristics of the film plane, and FIG. FIG. 4 is an operational waveform diagram of each part. F...Film, L...Lens, 10...CRT
, 20... Exposure control circuit, 30.40... Adder, 50a, 50b... Sample hold circuit, 6
0a, 60b...Analog-digital converter, 70
...Memory circuit, 80a, 80b...Digital-to-analog converter, 9o...Mono multivibrator.

Claims (1)

[Claims] A CRT image film retaking device displays an image on a CRT screen using position signals X, y and a luminance signal 2, and photographs the displayed image on a flat film through a lens, the image being determined by the position signals X, y. A memory circuit that stores correction data at the address, and adds the position signals X and y to each correction data output from the memory circuit, and
an adder for X-axis and YN that outputs as a T-deflection signal;
It is characterized by comprising an exposure control circuit that sends out a brightness signal controlled in accordance with a signal given from the memory circuit, and automatically correcting non-linearity and brightness reduction in the film-shot image. CRT image film photography device.