JPS60177A - Method for measuring density of picture - Google Patents

Abstract

PURPOSE:To measure simply and surely a luminous amount suitable for recording a picture by measuring the intensity of light representing black information among picture information on a faceplate and using the brightness as a reference. CONSTITUTION:The picture information f a video signal is displayed on a fluorescent faceplate 3 of a CRT. A part of the information representing the black information among the picture information, i.e., the luminance of a porch 6 or a part 13 (a part being background of a video signal 8) of a displayed faceplate 7 is measured. The proper luminous amount required for the picture recording is measured by referencing this brightness. The measurement of a proper luminous amount for the picture recording is attained simply and surely without requiring any special mechanism in such a way.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image density measuring method for measuring the appropriate amount of light required to record one image.

In a system that displays an image on a screen using a video signal and records the image on the screen on a recording medium, even though the video signal is appropriate, due to circuit characteristics such as temperature A, the image on the screen is The signal may not be output as expected and the brightness may change. For this reason, when conventionally recording an image, there is a difference in the brightness of the image information that makes up the image.

In order to accurately record the absolute value, it is necessary to measure the total amount of light that the image has, or to apply a reference light of known brightness to the recording medium immediately before or at the same time as recording the image, and then measure it. By doing this, the appropriate amount of light was determined, and based on this, the image on the screen was recorded on the recording medium.

By the way, when measuring the total amount of light that an image has, it is difficult to obtain an appropriate contrast value for recording the image, and when measuring it by applying it to the recording medium as a reference light, there is a need for a mechanism to generate a specific reference light. There were problems such as the need for a separate

The present invention was made against the background of the above circumstances, and an object of the present invention is to provide an image density measuring method that can easily and reliably measure the amount of 'X' suitable for recording an image without requiring a special mechanism. It is said that

In order to achieve the above object, the present invention measures the intensity of light representing black and white information of image information in an image recording system, and measures the appropriate amount of light necessary for image recording based on this luminance. It is characterized by what it has done.

An embodiment of the present invention will be described below based on the attached drawings [J
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Figure 1 is an overall configuration diagram showing an example of recording an image on a CRT onto a film, Figure 2 is an explanatory diagram showing the brightness on a CRT, and Figure 3 is a photometric device that measures the brightness of black information. It is a circuit diagram.

In the image recording system, a video signal from a video signal generator 1 is applied to a CRT 2, and a fluorescent screen 3 of the CRT 2 emits light in accordance with the intensity of the incident electron beam to display a visible image. This involves horizontally scanning an electron beam 4 on a fluorescent screen 3, turning it back in response to a horizontal synchronization signal 5, and scanning this repeatedly from top to bottom to make the fluorescent screen 3 emit light. When it reaches the lower part of 3, it turns around according to the vertical synchronization signal, moves upward, performs a similar scan, and outputs the next video signal, and the image information from the video signal generator 1 is displayed on the fluorescent screen 3 of the CRT 2. It is now possible to

By the way, a pouch 6 of a predetermined width is formed around the fluorescent screen 3, and image information is displayed inside this pouch 6. That is, as shown in FIG. 2, there is a front porch 6a and a back porch 6b between the horizontal synchronizing signal 5 at the turning point of scanning, and a display screen 7 is formed within the front porch 6a and the back porch 6b. ing. In this embodiment, an image end #8 is displayed at the center of the display screen 7.

By the way, the pouch 6 is a part that represents black information for setting a predetermined display screen 7, and this part emits light, albeit slightly, at the same level as the part that represents the blackest black information that can be expressed by the video signal. The brightness is . In other words, depending on the brightness and contrast adjustment, Pochiro is slightly emitting light. The 1s light device 9 is disposed facing a predetermined position so as to measure the brightness of the pouch 6 at this predetermined position on the fluorescent screen 3, thereby measuring the brightness of the pouch 6.

Then, using this luminance as a reference signal, the image measuring device IO measures the appropriate amount of light necessary for recording from the image on the fluorescent screen 3,
Further, the black information of this image information is returned to the original black information without light, and thereby the image is recorded on the recording body 12 by the recording device gill.

Further, in this embodiment, a portion 13 representing black information in the video information on the display screen 7 is set to have a brightness slightly higher than that of the pouch 6. Part 13 representing this black information
is provided to make the image information 8 in the central part clearer, and this part 13 can also be measured and used as a reference. That is, the portion 13 representing this black information is also set at a predetermined position on the fluorescent screen 3, and whether to measure this portion 13 or the pouch 6 as a reference depends on
Freely selectable. For example, if it is clear in advance that the part 13 that makes the video information 8 clear is approximately the same brightness as the pouch 6, this part 13 is measured; if it is not clear, or the part 13 is set. If not, measure the pouch 6 and use the brightness of this part as the reference.

The photometric device 9 is constructed as shown in Fig. MS3. That is, the light receiving element 14 converts the light received from the black information such as the pouch 6 or the background portion 13 of the video information 8 into an electrical signal, which is amplified and outputted by the operational amplifier 15, and this is used as the standard for the black information. Signal.

As described above, this invention measures the intensity of light representing black and white information of image information, that is, the absolute amount of light that is unrelated to the total amount of light, and measures the appropriate amount of light necessary for image recording based on the brightness. As a result, an appropriate contrast value can be obtained. Further, black information, which serves as a reference for brightness, is always included in the image information, and there is an advantage that a mechanism for generating a specific reference light is not required.

[Brief explanation of drawings]

Figure 1 is an overall configuration diagram showing an example of recording an image on a CRT onto a recording medium, Figure 2 is an explanatory diagram showing the brightness on a CRT, and Figure 3 is a photometric device that measures the brightness of black information. FIG. 1... Video signal generator 2... CRT 3...
Fluorescent screen 6... Pouch 7... Display screen 8...
・Video information 9...Photometering device 10...Image measuring device Figure 1 Figure 2 Monitor

Claims (1)

[Claims] In a system that records images on a screen, an image density measurement method that measures the intensity of light representing black and white image information on the screen, and measures the appropriate amount of light necessary for image recording based on this brightness.