JP2911126B2 - Image display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention converts the gradation of image data according to the setting status of a window function, and indicates the gradation-converted image data. Regarding an image display device that displays the content on a display,
In particular, the present invention relates to improvement of a technique for setting a window function for gradation conversion.

(Prior art) Conventionally, when displaying an image with a CT scanner or the like, the original density value of each pixel has a very wide dynamic range, whereas the dynamic range of the display density of a CRT as a display device is narrow. The pixel value of the original density value (original image data value) of each pixel is converted into a gradation by a window function that associates a pixel value of a portion to be read with a displayable density, and can be read by a display device. To be displayed.

In a conventional image display apparatus of this type, when setting a window function for gradation conversion, for example, as shown in FIG. 6, a window level: WL, which is a median of pixel values to be displayed in density, and a pixel to be displayed in density. A window function for gradation conversion has been set by using a parameter based on a window width: WW, which is a range of values, and adjusting the parameter according to an operator's judgment.

By setting the window function for gradation conversion in this manner, an image display with desired brightness and contrast on the display can be obtained.

(Problems to be Solved by the Invention) However, in the case of this type of conventional image display device, the operator must determine how to change the parameters in order to obtain a desired image display on the display. However, it is necessary to make the user feel intuitively by looking at the displayed image, and manual adjustment after the determination is troublesome.

The present invention has been made in view of the above problem, and has as its object to provide an image display device that can automatically set a window function for gradation conversion as desired by simply performing an operation by an operator. And

[Constitution of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention performs gradation processing by a window function indicating the relationship between image data values before gradation processing and display luminance. Display means for displaying an image based on image data and a gray scale as a sample of luminance, and an input capable of instructing an arbitrary position of the displayed image and a desired display luminance at the arbitrary position on the gray scale Instructing means, image data extracting means for obtaining an image data value before gradation processing corresponding to the input position specified by the input position, and pairing the image data value before gradation processing with the input display luminance. A window function setting unit that sets the window function based on at least one pair of the image data value before the gradation processing and the display luminance stored in the storage unit. Equipped with And wherein the Rukoto.

(Operation) With the image display device according to the present invention, for example, a point on the image on the display is indicated by a pointing device, and then the desired brightness on the gray scale of the display is specified by the same pointing device, and the floor is displayed. The window function for the tone conversion is automatically set. Therefore, the display of the desired brightness and contrast on the display can be immediately obtained by performing a simple operation.

(Embodiment) FIG. 1 is a block diagram showing an overall outline of an image display device according to an embodiment to which the present invention is applied.

The image display device of this embodiment functions as a control center of a system controller 1. The image signal obtained by imaging a subject is digitally converted by an A / D converter 2, and the digitized image signal is converted. (Hereinafter referred to as image data) is written into the image memory 3, the image data written into the image memory 3 is read out and sent to the mixer 4, where the image data is mixed with the output data of the gray scale generator 5, The A-converter 6 demodulates the signal into an analog signal and transmits the signal to the display 7, and the display 7 displays the content and gray scale corresponding to the image data as an image.

The system controller 1 has functions as an image data extracting unit 1a and a gradation specifying unit 1b,
The image data extracting means 1a controls the drive of the cursor generator 9 in response to an input operation of a pointing device 8 such as a mouse, and, when indicating a certain point of the image displayed on the display 7, responds to the indicated point. The calculated pixel value is obtained.

The gradation specifying means 1b controls the driving of the cursor generator 9 in response to the input operation of the pointing device 8 on the display brightness corresponding to the point indicated by the image data extracting means 1a on the gray scale displayed on the display 7. Specify by

Note that the image data extracting unit 1a and the gradation specifying unit 1b
The function operation is also performed by performing an input operation on the keyboard 10 instead of the pointing device 8.

Further, an image processing controller 11 for exchanging data with the system controller 1 is provided. The image processing controller 11 is provided with an external storage device 12 such as a magnetic disk device.

The image processing controller 11 itself has functions as a storage control unit 11a and a window function setting unit 11b, and the storage control unit 11a includes a pixel value indicated by the image data extraction unit 1a and a gradation indicated by the gradation designation unit 1b. The display luminance is stored in the external storage device 12 as a pair.

The window function setting means 11b sets a window function for gradation conversion based on at least one or more pixel value-display luminance data pairs stored in the external storage device 12. In this embodiment, the least-squares approximation method and the interpolation method can be applied, but other methods can also be applied.

The least-squares approximation method has a characteristic as shown in FIG. 5A in which a pixel value-display luminance pair group is reduced to a linear function by least-squares approximation.

The interpolation method exhibits characteristics as shown in FIG. 5B obtained by performing interpolation such as spline interpolation and creating a function that passes through all specified pixel value-display luminance pairs.

Next, the operation of one embodiment of the present invention will be described with reference to the flowchart of FIG. 2 and the operation situation diagrams of FIGS. 3 and 4.

When one point in the image 13 displayed on the display 7 is indicated by a mouse click as a pointing device as shown by an arrow in FIG. 3 in response to a cursor operation by the pointing device 8 (step
201), the pixel coordinates of the designated point are recognized, and the pixel value that is the original image data value is read from the image memory 3 corresponding to the pixel coordinates. Next, when a desired scale value of the gray scale 14 displayed on the display 7 is designated as indicated by an arrow in FIG. 4 in response to a cursor operation by the pointing device 8, the display brightness of the designated point in the image 13 is displayed. Is specified (step 202).

When the pixel value of the designated point in the image 13 and the display base are thus obtained, the data pair of the pixel value and the display luminance is simultaneously stored in the external storage device 12 (step 203). Each time the above operation for obtaining a data pair is performed, a new data pair is sequentially stored in the external storage device 12. Each time this storage is performed, that is, each time a new pixel value-display luminance data pair is additionally stored,
By using more data pairs including the new pixel value-display luminance data pair, in a least squares method or an interpolation method,
A more appropriate window function setting process is executed (step 20).
4) Based on the window function indicated by the processing result, the image data written in the image memory 3 is sequentially subjected to gradation conversion. Therefore,
The image 13 on the display 7 is an image whose gradation has been converted as indicated by the gray scale 14.

At this time, if the image on the display 7 is in a state of denying that the image quality desired by the operator is different (No in Step 205), Step 201 to Step 205 are repeated. When the image 13 on the display 7 has the image quality as desired by the operator (Yes at Step 205), the image quality adjustment ends.

As described above, according to the embodiment of the present invention, the gradation of the image 13 on the display 7 can be converted as desired only by performing the cursor operation using the pointing device 8 or the keyboard 10.

[Effects of the Invention] As described above, according to the present invention, after designating a desired position of an image, simply instructing a desired display luminance of the desired position on a gray scale, the image is automatically converted to a desired image. Therefore, it is possible to provide an image display device in which operability for obtaining a display of desired brightness and contrast is significantly improved as compared with the related art.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment to which the present invention is applied, FIG. 2 is a flowchart showing a processing flow of the apparatus of FIG. 1, and FIGS. 3 and 4 are operating states, respectively. FIG. 5 is a characteristic diagram schematically showing a method of setting a window function for gradation conversion, and FIG. 6 is a characteristic diagram schematically showing the principle of changing the window function. DESCRIPTION OF SYMBOLS 1 ... System controller, 2 ... A / D converter 3 ... Image memory, 4 ... Mixer 5 ... Gray scale generator, 6 ... D / A converter 7 ... Display 8 ... Pointing device 9 Cursor generator, 10 Keyboard 11 Image processing controller 12 External storage device

Claims (1)

(57) [Claims] A display means for displaying an image based on image data subjected to gradation processing by a window function indicating a relationship between image data values before gradation processing and display luminance, and a gray scale as a sample of luminance; Input instructing means capable of instructing an arbitrary position of the displayed image and a desired display luminance at the arbitrary position on the gray scale; and image data before gradation processing corresponding to the input and designated arbitrary position Image data extracting means for obtaining a value, storage means for storing the image data value before the gradation processing and the display luminance instructed to be input in pairs, and at least one pair of the storage means stored in the storage means. And a window function setting unit configured to set the window function based on a pair of the image data value before the gradation processing and the display luminance.