JPH0734219B2 - Region of interest designator - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention belongs to the field of an image processing apparatus for a grayscale digital image, and more specifically, in the grayscale digital image, a region of interest (hereinafter, “region of interest”) which is a connected region. "ROI").

[Technical background of the invention and its problems]

As the ROI designation (setting) method, for example, a method in which the operator directly inputs the ROI coordinates using a trackball, joystick, etc. on the display image, or in the display image (or in the roughly designated ROI), All pixels within the tint range specified by the operator (Pi
xel) is generally used as the ROI.

By the way, in the method in which the operator directly inputs the ROI coordinates using the trackball or the like, it is necessary to draw a complicated shape with the trackball or the like, and this scanning is extremely difficult for the operator.

Further, the method of setting all pixels included in the grayscale range designated by the operator as ROIs may include irrelevant (unnecessary) pixels in ROIs, particularly in ROI designation in a region of the display image where the grayscale difference is small. Furthermore, there is a risk that the ROI will not be a connected region (ROI will be separated into two or more regions).

[Object of the Invention]

The present invention has been made in view of the above matters, and it is a connected area on a display image that is accurately and easily even if the area has a small grayscale difference and the area has a complicated shape. It is an object of the present invention to provide a region-of-interest specifying device capable of specifying the ROI of a.

[Outline of Invention]

The outline of the present invention for achieving the above-mentioned object is, in a region of interest designating apparatus for designating a region of interest for an image displayed on a display, a region to be set as a region of interest in an image displayed on the display. The setting means for setting the representative position, the means for selecting a pixel adjacent to the representative position set by the setting means, and having a grayscale value having a value substantially equal to the grayscale value of the representative position, and the selecting means. Change means for arbitrarily changing the size of the connection area formed by the selected pixels by operation, and pixels formed by the selecting means and changed in size by the changing means. It is characterized by further comprising display means for displaying the connected area so as to be distinguishable from the others.

Example of Invention

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

FIG. 1 is a block diagram showing a configuration of a region-of-interest designating device according to the present invention. In the figure, the input means 1 is operated by an operator when the ROI is designated in the present apparatus, and its front panel has an enlargement key 6, a reduction key 7, and a completion key as shown in FIG. 2, for example. 8, trackball
A set button 9, a trackball on button 10, a trackball 11 and the like are arranged. Then, the various designation signals output from the input means 1 are connected so as to be input to the computer 2.

On the other hand, an image memory 3 and a graphic memory 4 are arranged between the computer 2 and the display 5. The image memory 3 stores gray-scale image data, and the graphic memory 4 stores black-and-white binary graphic image data (used for ROI shape and the like). It is provided for display on the display 5 based on the command.

The operation of the region-of-interest designating device configured as described above will be described with reference to the main flowchart of FIG. Based on the command from the computer 2, the image memory 3
The image data stored in is displayed on the display 5. Operator has trackball on button
When you press 10, the computer 2 turns on the graphics memory 4
The dot-shaped pattern is displayed (superimpose) on the image of the display 5 using. The operator turns the trackball 11 to move the dot-shaped pattern to a region of interest (region for which ROI designation is desired). When the operator presses the trackball set button 9, the computer 2 recognizes the dot-shaped pattern position at that time as a point designated by the operator. The point specified in this way is considered as a temporary approximation of ROI described later. Hereinafter, this provisional area is referred to as a "Z-area" for the sake of description.

Next, the operator keeps pressing the expansion key 6 to gradually expand the Z-area to obtain the desired ROI.
Move closer to the designated area. The operator keeps pressing the enlargement key 6 while pressing the Z-key displayed on the display 5.
When the area is constantly monitored and it is determined that the Z-area is in good agreement with the desired ROI area, the pressing of the enlargement key 6 may be stopped.

After that, the Z-area is compared with the desired ROI area, and if the Z-area is smaller than the desired ROI area, the expansion key 6 may be pressed again to expand the Z-area. If the area is larger than the desired ROI area, the Z-area can be reduced by pressing the reduction key 7.

Then, the operator again selects the Z-area and the desired ROI.
When it is judged that the Z-area and the desired ROI area match well with each other, the completion key 8 is pressed. The computer 2 recognizes the Z-area at that time as the ROI area.

Next, the algorithm executed by the computer 2 in this apparatus will be described with reference to the flowcharts shown in FIGS.

First, as the main variables used to explain the algorithm, A variable whose value is a set of pixels in the Z-area, Variable whose value is a subset (subset) of pixels adjacent to the Z-area, k ₁ , k ₂ : variables that take integer values, n: number of pixels included in the Z-area, and shape of the Z-area There is a stack that has as an element.

The main function is K (P): the gray value of the pixel P.

The main procedure is To the stack, Pop the stack, Put in, The outline of is displayed on the display.

FIG. 4 shows OP1 in the main flow chart shown in FIG.
7 is a flowchart for explaining an algorithm of (point designation). First, with the trackball 11, the coordinates of the points
Get P ₀ (step 12). Next, the coordinates P ₀ Further, k ₁ and k ₂ are respectively set to the gray value of the coordinates P ₀ of the point, and the stack is emptied (step 13). next, Push (step 14) to finish the point designation.

FIG. 5 shows OP2 in the main flow chart shown in FIG.
It is a flow chart for explaining the algorithm of (expansion). First, All pixels adjacent to And the pixel numbers n and c are set to 0 (step 15). Next, it is determined whether or not the enlargement key 6 is pressed (step 16). In the determination in step 16,
When it is determined to be no, the execution of this algorithm ends, and when it is determined to be yes, that is, when the expansion key 6 is pressed, Select any one element of, and let this be P. And Subtract P from And (Step 17). Next, the gray values k ₁ and k ₂ and the P
Is compared with the gray value of (step 18). Step 18
When it is judged as yes in the comparison of And the set sum of P and And (ie To enlarge). And said enlarged Is displayed on the display 5, and 1 is added to each of the pixel numbers n and c (step 19). Then the above Since was last pushed onto the stack, Increased due to the expansion of It is determined whether or not the increment c in the number of pixels of is larger than a certain fixed number of pixels c ₀ (step 20). If the answer in step 20 is YES, then Is pushed onto the stack (used for reduction described later), and the pixel number c is set to 0 again (step 21). next, Determines whether is an empty set φ (step 2
2). The determination in step 22 is also performed when the determination in step 18 is no, and when the determination in step 20 is no. Then, in the determination in step 22, if the determination is no, the procedure returns to the determination in step 16, and if the determination is yes, it is determined whether or not the number of pixels n included in the Z-area is 0. It is determined whether or not (step 23). When it is determined as yes in the determination of step 23 (that is, it means that the determination results of step 18 in the processing of OP2 are all no), subtract ₁ from the grayscale value k _1. , 1 is added to the grayscale value k ₂ (that is, the width between k ₁ and k ₂ is widened), and the process returns to step 15. Also, when it is determined no in the determination in step 23, the same step as described above is performed.
Return to 15. Here, the following relationships are always established in this algorithm. ^∀ P (P ∈ Z → k ₁ K (P) k ₂ ) (1) That is, The gray value of any pixel contained in is between k ₁ and k ₂ . Also, Is always a connected region.

FIG. 6 shows OP3 in the main flow chart shown in FIG.
It is a flow chart for explaining the algorithm of (reduction). First, it is determined whether or not the stack is empty (step 25). In the determination in step 25,
When it is determined to be no, in step 21 of the OP2, the Z-area pushed on the stack is popped and displayed on the display 5 (that is, the Z-area pushed last). Is reproduced). And
After waiting for a fixed time (step 27), it is determined whether or not the reduction key 7 is pressed (step 28). Also, when the determination in step 25 is YES, the determination in step 28 is performed after waiting for a certain period of time, as described above. When the determination in step 28 is yes, that is, when the reduction key 7 is pressed, the process returns to the determination in step 25. If it is determined no in step 28, that is, if the reduction key 7 is not pressed, the execution of this algorithm is terminated.

FIG. 7 shows OP4 in the main flow chart shown in FIG.
It is a flow chart for explaining the algorithm of (the ROI designation is completed by the completion key). By pressing the completion key 8, Is the ROI (step 29). This completes the ROI designation.

The ROI designated in this way is used for property analysis of a specific portion on the display screen by, for example, obtaining the gray value distribution of pixels in the ROI in the display image or the area of the ROI.

It is needless to say that the present invention is not limited to the above embodiments and includes various modifications within the scope of the gist of the present invention. For example, in the CT device, when it is known in advance that the center of the image is included in the ROI, such as when specifying the ventricular quality of the head image as ROI, OP1 (point designation of the point in the above embodiment ) Can be omitted and the center of the image can be used instead of the point to be specified. Further, the enlargement key and the reduction key may be, for example, a tapping operation of the keys, instead of pressing them continuously, or
Instead of the key, a trackball may be provided and the trackball may be continuously rotated.

INDUSTRIAL APPLICABILITY The present invention can be applied to any gray scale display device including a computer or connected to the computer.

〔The invention's effect〕

According to the present invention described above, even in a region having a small grayscale difference, and even in a complicated shape, the operator presses the enlargement key or the reduction key to accurately and easily, It is possible to provide a region-of-interest designating device that enables ROI designation of a target region.

[Brief description of drawings]

FIG. 1 is a block diagram showing a region-of-interest designating device according to the present invention, FIG. 2 is a schematic diagram showing an example of a display panel of an input means of the device shown in FIG. 1, and FIG. 3 is a device shown in FIG. FIG. 4 to FIG. 7 are main flow charts for explaining the operation of the above, and FIGS. 4 to 7 are flow charts for explaining the algorithm of the apparatus shown in FIG. 1 ... input means, 2 ... computer, 3 ... image memory, 4 ... graphic memory, 5 ... display.

Claims (1)

[Claims] 1. An image displayed on a display,
In a region-of-interest designating device for designating a region of interest, setting means for setting a representative position of a region to be set as a region of interest in an image displayed on the display, and adjacent to the representative position set by this setting means, Means for selecting a pixel having a gray value substantially equal to the gray value of the representative position, and changing means for arbitrarily changing the size of the connection area formed by the pixels selected by the selecting means by an operation. And a display unit for displaying the connected region formed by the pixels selected by the selecting unit and changed in size by the changing unit so as to be distinguishable from others. ROI specifying device.