JPH01149581A - Hard copy device - Google Patents

Abstract

PURPOSE:To set the gradation characteristic of a CRT display device at the ideal characteristic curve of a film by obtaining density difference information from a hard copy and the gradation characteristic curve of the film and correcting the brightness contrast of the CRT from this. CONSTITUTION:When a density difference d1 of the characteristic curve of a gradation level 9 is inputted to a change quantity converting part 1, a change quantity in accordance with this is outputted to a brightness controller 2 and the controller 2 controls the brightness of a CRT display device 3. On the other hand, a density difference signal d2 of the characteristic curve of a gradation level 12 and the output of the converting part 1 are inputted to a density difference normalizing part 4, the normalizing part 4 converts them into a density difference d3 when the brightness is adjusted and outputs it to a change quantity converting part 5. The converting part 5 converts the output and outputs an analog signal in accordance with the density difference d3 as the contrast control signal of the display device 4. As this result, the gradation characteristic of the display device 4 can be set to the ideal characteristic curve of film 4.

Description

[Detailed Description of the Invention] [Object of the Invention] (Field of Industrial Application) The present invention is applicable to CT scanners and magnetic resonance imaging devices (M
A video signal of a diagnostic image obtained from a medical image diagnostic device such as HI) is input to a multi-format camera, which is a CRT imager, and the image displayed on the CRT display inside the imager is passed through an optical system onto the film surface. The present invention relates to a hard copy device that forms an image to obtain a hard copy image.

(Prior Art) In medical image diagnostic equipment such as CT scanners and MRI, there is a CRT monitor on the main body side, and diagnostic images are displayed on this monitor. A hard copy device displays an inverted image of the same image on the CRT display inside the imager by inputting it to the camera, and forms this image on the film surface using an optical system to obtain a hard copy image. It is equipped.

By the way, in conventional hard copy devices,
In order to make initial settings so that the Ni1l characteristics of the CRT display match the ideal gradation characteristic curve of the film, it is necessary to actually take pictures on the film surface and experience the brightness and contrast of the CRT display. I tried to make adjustments based on my intuition and through trial and error.

In this case, it is possible to grasp approximately how the gradation characteristics of the CRT display change depending on brightness, contrast, and photographing time. That is, it can be seen that by adjusting the brightness of the CRT display, the characteristic curve of the hard copy changes in gradation due to brightness with a constant slope and moves in parallel as shown in FIG. In addition,
In Fig. 4, the X axis is the logarithm of the light amount, but for convenience, 16
It is expressed as a stage level. Furthermore, it can be seen that when the contrast of the CRT display is changed, the slope changes around a certain density, as shown in FIG. In addition, in FIG. 5, the slope is shown as changing around a density of 1.0.

(Problem to be solved by the invention) However, it is difficult to understand how the characteristic curve of a hard copy changes by adjusting the brightness and contrast of the CRT display or by changing the shooting time. Even if it is possible, for example, the characteristic curve of hard copies will vary depending on the location, the automatic developer used, and the film, due to the influence of the concentration of the developer in the automatic processor, or when the equipment is moved. Therefore, it has been difficult to immediately match the gradation characteristics of the CRT display to the conditions of the ideal gradation characteristic curve of the film.

The present invention obtains density difference information from the gradation characteristic curve of a hard copy at a certain point in time and the gradation characteristic curve of an ideal film, and uses this density difference information to control brightness and contrast for a CRT display. By correcting, CRT
Display ll1r! It is an object of the present invention to provide a hard copy device that can set a characteristic curve of a film that idealizes A characteristics.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention converts diagnostic images obtained from a medical image diagnostic device such as a CT scanner or a magnetic resonance imaging device into a CRT imager. A hard copy device that obtains a hard copy image by displaying an image on a CRT display and focusing the image on a film surface using an optical system, comprising: a brightness control means for controlling the brightness of the CRT display; Contrast control means for controlling contrast and density difference information between a gradation characteristic curve based on brightness and contrast of a CRT display at a certain point in time measured around a desired density value of an ideal gradation characteristic curve of a film. The apparatus further comprises a converting means for obtaining a change amount for adjusting the brightness and contrast of the CRT display based on the above, and applying the change amount to the brightness III flJ means and the contrast control means as a correction signal.

(Function) Therefore, in a hard copy device having such a configuration, density difference information and contrast corresponding to brightness obtained from an ideal film gradation characteristic curve and a hard copy gradation characteristic curve at a certain point in time are obtained. The density difference information corresponding to the gradation characteristics is converted into brightness change amounts and contrast change amounts to perform brightness and contrast corrections that control the CRT display, so that the characteristics of the film that idealizes the gradation characteristics of the CRT display are corrected. It becomes possible to easily set the curve.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of the configuration of a hard copy apparatus according to the present invention. In FIG. 1, reference numeral 1 denotes a brightness change amount converting section, and this change amount converting section 1 has a brightness change amount converting section 1 which has a brightness change amount converting section 1. A density difference signal Δdl between the density value and the density value of the gradation characteristic curve based on the plinth is input. Reference numeral 2 denotes a brightness control section that corrects the brightness that controls the CR7 display 3 in accordance with the amount of change input from the brightness change amount converting section 1. Reference numeral 4 denotes a density difference normalization unit, and this density difference normalization unit 4 calculates the brightness at a certain point in time corresponding to the gradation degree obtained based on the second measurement point of the ideal gradation characteristic curve of the film. The density difference signal Δd2 with respect to the gradation of the gradation characteristic curve and the amount of change from the brightness change amount converter 1 are respectively input, and the brightness controller 2 adjusts the brightness according to the amount of change output from the brightness change amount converter 1. is converted into a density difference signal Δd3 in the case where Δd3 is corrected. Reference numeral 5 denotes a contrast change amount converter to which the density difference signal Δd3 from the density difference normalizer 4 is input, and this change amount converter 5 outputs a change amount according to the density difference signal Δd3. Reference numeral 6 denotes a contrast control section that corrects the contrast that controls the CR7 display 3 according to the amount of change inputted from the change amount converting section 5. Note that 7 in the figure is a film on which the inverted image displayed on the CR7 display 3 is formed through a lens 8 as an optical system.

FIG. 2 shows an example of the internal configuration of the brightness control section 2 using a block circuit, and the brightness control section 2 is composed of a pulse generator 2a, an up/down counter 2b, and a digital/analog converter 2C. The pulse generator 2a receives a change amount (
When a certain digital value (for which the amount of change per value is established by design) is input, the number of pulses corresponding to that value is sent as an up-clock signal if the amount of change is positive.

If it is negative, it is output as a down clock signal. Further, the up/down counter 2b changes the contents of the counter when an up clock or down clock signal is input from the pulse generator 2a, and performs digital/analog conversion! 12C converts the count value outputted from the up/down counter 2b into an analog signal and outputs this as a brightness control signal.

Although FIG. 2 shows the internal configuration of the brightness control section 2,
The contrast control unit 4 also has an internal configuration that is exactly the same as this, so the explanation thereof will be omitted here.

Next, the operation of the hard copy apparatus constructed as described above will be described with reference to the hard copy gradation characteristic curve shown in FIG. Here, in FIG. 3, A is the ideal characteristic curve, B is the characteristic curve at a certain point in time, and C is the gradation level 9 when centering on the density value 1.0 in the ideal characteristic curve. The characteristic curves are shown when the brightness is adjusted based on the reference.

Now, the ideal characteristic curve mA at gradation level 9 and the characteristic curve B at a certain point are stored in the brightness change amount converter 1.
and the density difference Δdl between the ideal characteristic curve A at gradation level 12 and the characteristic curve B at a certain point in time.
d2 and the density difference signal Δd1.
is input to the brightness change amount converter 1, and the density difference signal Δd2 is input to the density difference normalizer 4. The brightness change amount conversion section 1 inputs the change amount according to the density difference signal Δdl as a digital value to the brightness control section 2 and the density difference normalization section 4, respectively. In the brightness control section 2, when the amount of change from the brightness change amount conversion section 1 is input to the pulse generator 2a shown in FIG. 2, an up or down clock signal is generated depending on whether the amount of change is positive or negative. is output according to its value. Here, to the concentration difference signal d
Since the amount of change corresponding to 1 is negative, the down clock signal is input to the up/down counter 2b. Therefore, the up/down counter 2b changes the count value in the down direction and inputs its output to the digital/analog converter 2C. When the output of the up/down counter 2b is applied to the digital/analog converter 2c, it is converted into an analog signal according to the density difference signal Δdl, and the brightness of the CR7 display 4 is controlled.

As a result, the characteristic curve B at a certain point in time shown in FIG. 3 becomes a characteristic curve C that is parallelly shifted to a point passing through gradation level 9 of the ideal characteristic curve A.

On the other hand, when the aforementioned density difference signal Δd2 and the amount of change from the brightness change amount converter 1 are respectively input to the density difference normalization unit 4, the density difference normalization unit 4 calculates the density difference when the brightness is adjusted. .

That is, it is converted into a density difference signal Δd3 between the ideal characteristic curve A at gradation level 12 and the parallel-shifted characteristic curve C, and this is input to the contrast change amount conversion section 5. When the amount of change corresponding to the density difference signal Δd3 is input to the contrast change amount converter 5 to the contrast controller 5 having the same configuration as that shown in FIG. The digital/analog converter outputs an analog signal corresponding to the density difference signal Δd3 as a contrast control signal for the CR7 display 4 through the digital/analog converter. As a result, the characteristic curve IIC shown in FIG. 3 is equivalent to rotating the ideal characteristic curve A around a point passing through gradation level 9 so as to overlap the ideal characteristic curve A, and CR7 It becomes possible to set the gradation characteristics of the display device 4 to the ideal characteristic curve of the film.

In this example, in the hard copy gradation characteristic curve shown in FIG. 3, there is an ideal characteristic curve A that is measured with level 9 as the first measurement point to the gradation with a density value of 1.0. The brightness difference signal Δd from the characteristic curve B is given to the brightness change amount converter 1 to obtain the change amount, and this is added to the brightness controller 2 to convert the brightness of the CR7 display 4 to the density difference signal Δd1. The density difference signal Δd2 between the ideal characteristic curve A and a certain characteristic curve B, which were adjusted to the corresponding signal level and measured using the gradation level 12 as the second measurement point, and the brightness change amount converter 1 Characteristic curve A made ideal by giving the change amount to the density difference normalization unit 4
When the brightness is adjusted, the contrast of the CR7 display 4 is adjusted by obtaining a density difference signal Δd3 between the characteristic curve C and the contrast change amount converter 5 and giving the change amount converted by the contrast change amount converter 5 to the contrast controller 6. Concentration difference signal Δ
I adjusted the signal level to correspond to d3, so
It is possible to set the gradation characteristics of the CR7 display 4 to the characteristic curve of the target film.

Therefore, there is no need to adjust the Nm characteristics of the hard copy to the ideal one by actually shooting on film and adjusting the gradation level of the CR7 display 4 based on experience or some kind of intuition, as in the past. The characteristics can be easily set to the ideal gradation characteristics of the film in a short time.

In the above embodiment, a hard copy was described in which the density value was centered at 1.0 in the gradation characteristic curve shown in FIG. 3, but in general, the center of contrast is
The density values differ depending on the 11 systems, and are not necessarily limited to the above-mentioned density values. Also, the concentration difference signal Δdl
As the brightness change amount conversion unit 1 that converts d1 into a change amount, an arithmetic circuit that calculates the change amount every time d1 is input to the density difference signal may be used. Prepare a table in which is written,
A memory may be used that reads the amount of change corresponding to the concentration difference signal at that time from this table.

[Effects of the Invention] As described above, according to the present invention, density difference information is obtained from the gradation characteristic curve of a hard copy at a certain point in time and the gradation characteristic curve of an ideal film, and this density difference information is also used. Toni CR
Since the brightness and contrast that control the T display are corrected, it is possible to provide a hard copy device in which the gradation characteristics of the CRT display can be easily set to the ideal film characteristic curve.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram showing an embodiment of a hard copy apparatus according to the present invention, FIG. 2 is a block diagram showing the internal configuration of a brightness control section in the embodiment, and FIG. 3 explains the operation of the embodiment. Fig. 4 is a gradation characteristic curve diagram of a hard copy when changing the brightness of a CRT display, and Fig. 5 is a gradation characteristic curve diagram when changing the contrast of a CRT display. It is a characteristic curve diagram. 1...Brightness change amount conversion section, 2...
... Brightness control section, 3 ... CRT display, 4 ... Density difference normalization section, 5 ... Contrast change amount conversion section, 6 ... Contrast control section. Applicant's agent Patent attorney Kainori Suzue Takehiko Figure 4

Claims (1)

[Claims] Hardware that displays a diagnostic image obtained from a medical image diagnostic device such as a CT scanner or magnetic resonance imaging device on a CRT display inside a CRT imager, and forms the image on a film surface through an optical system to obtain a hard copy image. In a copying apparatus, a brightness control means for controlling the brightness of the CRT display, a contrast control means for controlling the contrast of the CRT display, and a measurement centering on a desired density value of an ideal film gradation characteristic curve. The amount of change for adjusting the brightness and contrast of the CRT display is obtained based on the density difference information with the gradation characteristic curve due to the brightness and contrast of the CRT display at a certain point in time. 1. A hard copy device comprising: conversion means for providing a correction signal to contrast control means.