JPH0898086A - Display device for television camera image - Google Patents

Abstract

PURPOSE: To obtain a sharp image display by setting optionally an output luminance correction characteristic curve with respect to an input video image so as to attain contrast adjustment in response to a luminance level. CONSTITUTION: A luminance correction characteristic obtained by a prescribed arithmetic operation is displayed on a screen by using luminance of television camera image input data for the X-axis and display luminance for the Y-axis corresponding to the X-axis and an optional point is selected and changed by a mouse. Image data from a camera are stored in an image memory 11 for a prescribed period, an image processing section 13 reads the data in the unit of picture elements, displayed luminance is obtained according to the luminance characteristic curve and stored in a display memory 12. The processing above is repeated and an image subject to luminance correction for entire picture elements is processed by a display update processing section 15 and the result is displayed on the screen. Thus, contrast is emphasized in an intermediate tone and an image with luminance changed at a large difference has smaller contrast and then the desired contrast is adjusted depending on the luminance level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to brightness adjustment of television camera images.

In particular, for example, a plurality of television camera images are displayed by connecting one or a plurality of television camera devices installed at a remote location and a display device in a centralized monitoring center for centrally monitoring the television camera images by a transmission medium. Display on the device,
The present invention relates to adjustment of display brightness of TV camera images in a system such as a system for grasping the situation of a remote place or monitoring crime prevention.

[0003]

2. Description of the Related Art In a conventional brightness adjustment method for a television camera image or a display device, the brightness adjustment voltage is varied by turning a knob of one variable resistor to uniformly adjust the video amplification gain. Therefore, the conventional display device can brighten or darken the entire screen or enhance the contrast, but it is not possible to make the above adjustment for a specific portion of the image on the display device. It was impossible. Further, it was not possible to make adjustments such as emphasizing contrast in dark places and weakening contrast in bright places.

[0004]

In the above-mentioned conventional method, since the image amplification gain is adjusted uniformly, the contrast of the intermediate luminance level is emphasized and the contrast of the high luminance and the low luminance is reduced to obtain a clear image. It is impossible to display a different image, increase the contrast of low brightness, emphasize an image only in a dark place, and adjust the contrast according to an arbitrary brightness level.

Further, in a device in which TV cameras are installed at a plurality of places and each TV camera image is displayed on one display device, depending on the place where the TV cameras are installed,
The brightness of the surrounding lighting is different, and the brightness of the image of each TV camera is different. In this case, if the brightness of the display device is adjusted by the conventional method, the brightness of the entire display screen changes, and it is difficult to adjust the brightness for each television camera image unit. Also, with a TV camera,
If the display devices are far apart, each TV camera image unit needs to be adjusted, so the TV camera device side must make adjustments. Therefore, use a remote control or another person (operator) to adjust the TV camera side. It was necessary to adjust it while contacting with each other, and not only was it a very expensive device, but it was technically difficult.

[0006]

In order to achieve the above object, the present invention is to arbitrarily set an output luminance correction characteristic curve for an input image.

Further, the brightness correction characteristic curve is displayed on the display device.

[0008]

The brightness correction characteristic curve is displayed on the display device, and the values of arbitrary points (for example, X and Y) of the brightness correction characteristic curve are changed to arbitrarily set the brightness correction characteristic curve. Furthermore, the display brightness of a plurality of TV camera images is corrected by preparing a plurality of brightness correction characteristic curves.

[0009]

EXAMPLE A method for calculating the display brightness of a TV camera image is as follows: the TV camera image data input brightness is taken as the X axis, and the Y axis value corresponding to the X axis is taken as the display brightness of the TV camera image. The brightness is calculated from the television camera image data by the following primary interpolation formula.

[0010]

[Equation 1]

However, DISP: display brightness of TV camera image CAM: TV camera image data (where X (i) ≦ CAM ≦ X (i + 1)) X (i): value of X axis interpolation point of brightness correction characteristic curve Y ( i): Value of Y-axis interpolation point of brightness correction characteristic curve FIG. 1 shows an example of the crime prevention monitoring system, which is a centralized monitor for centrally monitoring a plurality of TV camera devices 1A and 1B installed at a remote location. This is a system in which the display device 3 in the monitoring center 2 is connected by a transmission medium, and the plurality of television camera images are displayed on the display device 3 so as to grasp the situation at a remote place and perform crime prevention monitoring. Surveillance center 2
A display / change screen of a plurality of TV camera images 4 and brightness correction characteristics 5 is superimposed and displayed on the display device 3 therein.

An embodiment of a brightness correction method for a television camera image will be described below. FIG. 2 shows a display example of the display / change screen of the brightness correction characteristic curve (of the brightness correction characteristic curve change screen 5 of FIG. 1). By selecting the left and right arrows 6 and 7 with the mouse, the X coordinate value of the first and second break points of the graph is increased or decreased, and the X coordinate value of the break point of the graph is displayed in real time and at the same time the characteristic curve is displayed. Change. Also,
By selecting the up and down arrows 8 and 9 with the mouse, the Y coordinate value of the first and second break points of the graph is increased and decreased, and the Y coordinate value of the break point of the graph is displayed in real time and at the same time the characteristic curve is displayed. Change. Note that the buttons 10A and 10B of the TV camera 1A and the TV camera 1B are used to switch the brightness correction data table for the TV camera 1A and the TV camera 1B because the display screens are shared independently.

The above method is used to interactively create while looking at the brightness correction characteristic curve. Next, the brightness correction of the television camera image will be described with reference to the block diagram of the embodiment of FIG.

Image data from the television camera devices 1A and 1B is read in a cycle of a constant cycle and temporarily stored in the television camera image memory 11. When displaying the TV camera image on the display device, the camera image display processing unit 13 reads the contents of the TV camera image memory 11 pixel by pixel, and from this 1 pixel data and the value of the brightness correction characteristic curve described above. By calculating the display brightness of the TV camera image described above, the display brightness according to the brightness correction characteristic curve is obtained,
It is stored in the display memory 12. A processing flow of the camera image display processing unit 13 is shown in FIG.

By repeating the above processing for all the pixels, the brightness-corrected television camera image is processed by the display update processing unit 15 as shown in the operation explanation flow chart (FIG. 5) and becomes the display screen. FIG. 5 is a flowchart for explaining the operation of the brightness correction graph / display update processing unit 15.

[0016]

According to the present invention described above, (1) When a plurality of television camera images are superposed and displayed on one display device, the display device side can easily adjust the brightness for each television camera image. .

(2) By adjusting the brightness correction characteristic curve shown in FIG. 2, the contrast of the intermediate brightness level is emphasized, and the contrast adjustment according to the brightness level such as reducing the contrast of high brightness and low brightness is facilitated. Yes, it can display a clear image.

(3) In the case of a TV camera image in a dark place,
An image in a dark place can be displayed more clearly by emphasizing the contrast of low brightness.

(4) By making the inclination of the brightness correction characteristic curve negative, a positive image can be negatively displayed or a negative image can be positively displayed.

(5) Considering the brightness correction characteristic curve as a filter characteristic curve, it is possible to display or cut only an image having a specific brightness.

(6) Since the adjustment of a plurality of television camera images is realized by software, the adjustment circuit is not required, so that the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a diagram showing a display example of an embodiment of the present invention.

FIG. 3 is a block diagram of an embodiment of the present invention.

FIG. 4 is an operation flowchart of an embodiment of the present invention.

FIG. 5 is an operation flowchart of one embodiment of the present invention.

[Explanation of symbols]

1A, 1B TV camera, 3 display device, 4 camera image display screen, 5 brightness correction characteristic display change screen, 11
Camera image memory, 12 display memory, camera image display processing, 15 brightness correction graph display update processing

Claims (4)

[Claims] 1. A display device for a television camera image, wherein an output luminance correction characteristic curve for an input image captured by the television camera is arbitrarily set by linear approximation. 2. A television camera image display device having a television camera and a display device for displaying an image of the television camera, wherein the display device side corrects the image data from the television camera and the brightness correction of the display device. The display luminance of the television camera image is obtained from the characteristic curve, and the luminance correction characteristic curve of the television camera is arbitrarily set to adjust the contrast according to the luminance level of the television camera image on the display processing device side. Characteristic TV camera image display device. 3. A television camera image display device having a plurality of television cameras and a display device for displaying an image of the television cameras, wherein the display device side displays the image data from each of the television cameras and the display. The display brightness of each TV camera image is obtained from the brightness correction characteristic curve of the device, and the brightness correction characteristic curve of each TV camera is arbitrarily set in each TV camera unit, so that each TV camera image is displayed on the display processing device side. A television camera image display device, characterized in that the contrast peculiar to each television camera is adjusted according to the brightness level of the television camera. 4. The operator according to claim 2, wherein the television camera image and the brightness correction characteristic curve are displayed on the display device so that the operator can see the brightness correction characteristic curve and arbitrarily set the brightness correction characteristic curve in real time. A display device for displaying a TV camera image, which is characterized by being set.