JPH0727342B2 - Contrast setting device in image display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention is used for an image display device such as an X-ray tomography apparatus and the magnetic resonance tomography apparatus, and particularly for setting the contrast of a digital image. Regarding the device.

B. Conventional Technology Conventionally, in this type of image display device, in order to enhance the contrast of the digital image of the region of interest and make the image easier to see, the density range (hereinafter referred to as the window) that is the target of the enhancement process is An operating means for setting the central value and the density width thereof is provided. The following are known as such operation means.

One of them has an operation button for setting the center value of the window and an operation button for setting the window width. The operator operates each operation button to set the desired window. You can do it.

However, according to the method using such operation buttons,
The operator is required to operate each of the two operation buttons in order to set the window, which is troublesome.

Therefore, in order to eliminate such troublesomeness, operation means capable of setting the center value and width of the window by a so-called trackball has been proposed and implemented. As is well known, in a trackball, when an operator rotates a sphere whose upper portion is exposed on the operation panel surface in an arbitrary direction, a rotation amount detecting means attached to the sphere causes the rotation operation amount to be X and It is output as a displacement amount component in the directions of two axes orthogonal to the Y direction.

Conventionally, in the window setting operation means using this type of trackball, when the trackball is rotationally operated in the X direction, for example, the window width changes according to the rotational displacement amount in the X direction, and the trackball moves in the Y direction. When the rotary operation is performed in the direction, the center value of the window changes according to the rotational displacement amount in the Y direction.

In this case, it is difficult for the operator to accurately rotate the trackball in the X direction or the Y direction, and some deviation occurs in the rotation direction. It is inconvenient for one window setting value to change unintentionally due to such a slight deviation in the rotating operation direction. Therefore, in the conventional device, the sensing band and the dead band as shown in FIG. 5 are set. There is. FIG. 5 is a plan view of the trackball TB, and when the trackball TB is rotationally operated within the range of the sensing band indicated by the area A in the figure, ignoring the rotational displacement amount in the X direction, The center value of the window is changed based on the rotational displacement in the Y direction,
Similarly, when the trackball TB is rotationally operated within the range of the sensing band indicated by the region B in the figure, the amount of rotational displacement in the Y direction is ignored and the width of the window is determined based on the amount of rotational displacement in the X direction. It is converting. Then, a dead zone C is set between the sensing zones A and B, and when the trackball TB is operated within the dead zone C, both the rotational displacement amounts of X and Y are ignored. , The window setting value is not changed.

C. Problems to be Solved by the Invention However, the above-described conventional device has the following problems.

That is, it is not always easy to rotationally operate the trackball TB so as to fall within the range of the sensing band A or B as described above, and it may enter the dead band C. In particular, when the trackball TB is slightly displaced or the movement of the trackball TB is not smooth, the rotation direction of the trackball TB is in the dead zone C against the operator's intention.
I often come in. Therefore, although the operator is operating the trackball TB, the situation where the set value of the window does not change occurs, which hinders the operability of the window setting.

The present invention has been made in view of such circumstances, and when the trackball is used to perform window setting, even if a deviation occurs in the rotational direction of the trackball,
An object of the present invention is to provide a contrast setting device in an image display device having good operability, in which the window setting value corresponding to the deviation direction does not change, and the window setting value does not change due to the dead zone described above. I am trying.

D. Means for Solving the Problems The present invention has the following configuration in order to achieve the above object.

That is, the present invention provides a contrast setting device in an image display device in which the center value of a density range to be subjected to contrast enhancement processing and its density width are set by operating the trackball. A comparison that compares the amount of rotational displacement in the orthogonal biaxial directions based on the amount of rotation in each direction provided by the rotational amount detection means and the rotational amount detection means that detects the rotational amount in each of the orthogonal biaxial directions. Means, based on the rotational displacement amount in the axial direction of the large displacement amount detected by the comparison means,
According to the axial direction, based on the contrast value setting means for changing the center value of the density range to be the enhancement processing or its density width, and the setting value given from the contrast condition setting means, An image processing means for performing contrast enhancement processing is provided.

E. Operation According to the present invention, when the trackball is rotated, the rotation amount detecting means detects the rotation amounts of the trackball in the two orthogonal axes directions and gives the rotation amount to the comparing means. The comparing means compares the magnitudes of the rotational displacement amounts in the respective directions based on the rotation amounts in the two orthogonal directions. The contrast condition setting means corresponds to the larger one of the rotational displacement amounts judged by the comparison means (that is, the center value of the density range to be the emphasis processing, or its density width).
Change. The image processing means performs the contrast enhancement processing of the original image based on the contrast condition set by the contrast condition setting means.

F. Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a schematic configuration of a contrast setting device in an image display device according to an embodiment of the present invention.

In the figure, 1 _X and 1 _Y are driven rollers that extract the rotation of the trackball TB in the X and Y directions.
1 _X, 1 each _Y rotary encoder 2 _X, 2 _Y is connected. Rotary encoders 2 _X and 2 _Y are trackballs
It outputs pulse signals S _X and S _Y according to the rotation of TB in the X and Y directions. The up / down counters 3 _X and 3 _Y are the pulse signals S _X ,
Track ball TB by counting S _Y
The rotation amount of X in the X and Y directions is detected. The rotary encoders 2 _X and 2 _Y and the up / down counters 3 _X and 3 _Y described above correspond to the rotation amount detecting means in this invention.

The count values N _X , N _Y obtained by the up / down counters 3 _X , 3 _Y are given to the microcomputer 4. The microcomputer 4 has a function as a comparing means and a contrast condition setting means in the present invention. The specific function of the microcomputer 4 will be clarified in the operation description given later. The microcomputer 4
Based on the count values N _X and N _Y , the width W of the density range to be emphasized and the center value M thereof are output to the image processing circuit 5 as contrast setting conditions.

The image processing circuit 5 performs contrast enhancement processing on the original image stored in the image memory 6 according to the contrast condition given from the microcomputer 4, and gives the result to the display memory 8 via the look-up table 7. . The look-up table 7 is composed of a plurality of memories for gradation correction of the image signal subjected to the contrast enhancement processing by the image processing circuit 5. By inputting the input image signal as an address designation signal of each memory, data preset at each address is
It is output as an image signal whose gradation has been corrected. The operator can specify an arbitrary memory in the look-up table 7 in order to perform a desired gradation correction.

The image signal stored in the display memory 8 is given to the CRT 9, so that the image subjected to the contrast enhancement processing and the gradation correction is displayed on the CRT 9.

Next, the contrast setting operation in the above apparatus will be described with reference to FIG.

FIG. 2 is a flow chart showing the contrast setting operation sequence in the microcomputer 4.

The microcomputer 4 has an up / down counter 3 _X ,
It is monitored whether or not the trackball TB has been rotated by taking in the count values N _X and N _Y of 3 _Y at regular intervals and determining whether there is a change (step S
1). When the trackball TB is rotated, the count value N _X ′ N _Y ′ acquired last time and the count value acquired this time
The rotational displacement amounts ΔN _X (N _X ′ −N _X ) and ΔN _Y (N _Y ′ −N _Y ) in the X and Y directions are calculated by taking the difference between N _X and N _Y (step S2). Then, the magnitudes of the rotational displacement amounts ΔN _X and ΔN _{Y in} the two directions are compared (step S3), and the rotational displacement amount ΔN _{X in the} X direction is compared.
Is larger, the process proceeds to step S4 to change the window width W by a value corresponding to the rotational displacement amount ΔN _X. on the other hand,
If the rotational displacement amount ΔN _{Y in} the _Y direction is larger, the process proceeds to step S5 to change the window center value M by a value corresponding to the rotational displacement amount ΔN _Y.

By performing the above-mentioned processing by the microcomputer 4, as shown in FIG.
When the rotation operation is performed in the area of the sensing band A including the axis, only the window center value M changes according to the rotational displacement amount in the Y direction, and the rotation operation is performed in the area of the detection band B including the X axis. If so, only the window width W changes in accordance with the amount of rotational displacement in the X direction. As is apparent from FIG. 3, there is no dead zone between the sensing zones A and B as in the conventional apparatus shown in FIG. 5, so that if the operator rotates the trackball TB, The window setting value corresponding to the axial direction close to the rotation direction will change without fail.

Window setting value output from the microcomputer 4
W and M are given to the image processing circuit 5. Image processing circuit 5
Performs contrast enhancement processing based on these set values W and M, for example, based on the following arithmetic expression. In addition,
The following formula is an example in the case of displaying an original image with 256 gradations.

I = (256 / W) · (I _O −M) +127 0 ≦ I ≦ 255 In the above formula, I is the image density level after the contrast enhancement processing, and I _O is the density level of the original image (each pixel in this embodiment). Is displayed in 16-bit gradation). Among the original images shown in FIG. 4 (a), the density level is 750.
To emphasize the density range of 1250 to 1250, rotate the trackball TB to set the center value M of the window to 1000.
And set the window width W to 500. Such a window set value is appropriately displayed on the CRT 9 or the like according to a command from the microcomputer 4, so that the operator can easily confirm the current window set value. An image obtained by emphasizing the original image based on the window setting value set in this way is shown in FIG. 4 (b).

In the above embodiment, the rotary encoder 2 _X, 2 _Y of the pulse signal S _X, has been counted by S _Y the up-down counter 3 _X, 3 _Y, which may be counted by the microcomputer 4 .

G. Effect of the Invention As is apparent from the above description, according to the present invention, based on the larger rotational displacement amount of the rotational displacement amounts in the two orthogonal axis directions when the trackball is rotationally operated. ,
Since the center value or the density width of the density range that is the target of the contrast enhancement processing is changed, the contrast corresponding to the deviation direction when the trackball is not accurately rotated in the predetermined two orthogonal axes directions. There is no inconvenience that the condition changes, and since there is no dead zone in the direction of rotation of the trackball, there is no inconvenience that the contrast condition does not change even when the trackball is rotated, and a contrast setting device with good operability. Can be realized.

[Brief description of drawings]

1 to 4 are explanatory views of an embodiment of the present invention. FIG. 1 is a block diagram showing a schematic configuration of a contrast setting device, FIG. 2 is an operation flowchart, and FIG. 3 is a track. FIG. 4 is an explanatory diagram of the sensing band of the ball, and FIG. 4 is an explanatory diagram of contrast enhancement processing. FIG. 5 is an explanatory diagram of a sensing zone and a dead zone of a trackball in a conventional device. TB ... Trackball 2 _X , 2 _Y ... Rotary encoder 3 _X , 3 _Y ... Up / down counter 4 ... Microcomputer 5 ... Image processing circuit

Claims (1)

[Claims] 1. By manipulating a trackball,
The center value of the density range that is the target of contrast enhancement processing,
In a contrast setting device in an image display device for setting the density range, a rotation amount detecting means for detecting a rotation amount of each of the trackballs in two orthogonal axis directions, and each direction given by the rotation amount detecting means. On the basis of the rotation amount, the comparison means for comparing the magnitudes of the rotational displacement amounts in the two orthogonal axes, and the axial displacement amount of the displacement amount detected by the comparison means in the axial direction According to the contrast value setting means for changing the center value of the density range to be the enhancement processing or the density width thereof, and the contrast enhancement processing of the original image based on the setting value given from the contrast condition setting means. A contrast setting device in an image display device comprising an image processing means for performing.