TECHNICAL FIELD
The present invention relates to a method and a device for correcting a motion blurred image upon freezing and storing a diagnostic image in an ultrasonic apparatus.
TECHNICAL BACKGROUND OF INVENTION
In general, an ultrasonic diagnosis is performed by monitoring a region of interest in real time. Therefore, an ultrasonic apparatus generally not only processes ultrasonic signals in real time so as to monitor a region of interest in real time but also provides a freeze function so as to observe an image in a stationary state in which a target object does not move.
In a conventional ultrasonic apparatus, a freeze function is performed when a freeze button is pressed. Consequently, there is an inconvenience that a user should press the freeze button with one of both hands while holding a probe in the other hand so as to freeze a diagnostic image being monitored in real time by the user. Therefore, a shaking of the probe occurs frequently due to a button press operation to cause motion blurs in the diagnostic image. As a result, it may be difficult to obtain a diagnostic image meeting a user's expectation such that the user should again obtain a new diagnostic image.
TECHNICAL SOLUTION
An object of the present invention is to provide a user with a diagnostic image having a minimized motion blur by correcting motion blur occurring in a freeze image when the user obtains the freeze image through a freeze function of an ultrasonic diagnosis apparatus and then the obtained freeze image is determined as a motion blurred image by measuring a motion blur factor of the obtained freeze image.
DESCRIPTION OF DRAWINGS
FIG. 1 is a block diagram of an ultrasonic apparatus according to the present invention.
FIG. 2A is a view illustrating an example of a basic form of a 3×3 edge filter.
FIG. 2B is a view for describing an embodiment of an edge filter employed in the present invention.
FIG. 3 is a view for describing a method for setting a threshold value according to the present invention.
FIGS. 4A and 4B are views illustrating images according to occurrence and nonoccurrence of motion blurs and motion blur factors.
FIG. 5 is a flowchart of a process for storing non-motion blurred images in real time according to the present invention.
FIG. 6 is a flowchart of a process for correcting a motion blurred image when a user generates events of an image freezing and an image storing according to the present invention.
FIG. 7 is a view illustrating an embodiment of an image which the user wants to freeze.
FIG. 8 is a view illustrating an embodiment of a motion blurred image by the user's mistake.
FIG. 9 is a view illustrating an example of a method for providing a non-motion blurred image by verifying whether or not motion blurs occur according to the present invention.
FIG. 10 is a view illustrating an embodiment of a user interface (UI) according to the present invention.
MODES OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
A configuration according to the present invention is shown in FIG. 1. An image stabilizer is a block proposed by the present invention, and is arranged behind an image storage CINE and in front of an image output device, which are equipped in a typical ultrasonic diagnosis apparatus. The image stabilizer receives images being currently processed from the image storage in real time, and determines whether or not motion blurs occur in the processed images to output non-motion blurred images.
As shown in FIG. 1, the image stabilizer is comprised of three blocks, that is, a motion blur factor calculator, a motion detector, and a stabilized image store. The motion blur factor calculator serves to convert a magnitude of motion blur in a received image into a motion blur factor to transmit the motion blur factor to the motion detector. At this point, the conversion from the magnitude of motion blur into the motion blur factor may be calculated using a variation rate of an edge image of a current image with respect to a previous image.
The motion blur factor calculator may calculate from edge images (GN and GN−1) of two images (an N−1th image and an Nth image) as follows.
In particular, the motion blur factor calculator may use a 3×3 edge filter shown in FIG. 2A so as to calculate a motion blur factor. In FIG. 2A, f(j,k) may mean a pixel value at a jth column and a kth row of a CINE image. Using the 3×3 edge filter according to Equation 1, a pixel value Gx(j,k) of an X-axis edge image and a pixel value Gy(j,k) of a Y-axis edge image at a jth column and a kth row may be obtained.
In Equation 1, K is determined depending on a kind of an edge filter to be used, and FIG. 2B shows edge filters employed in the present invention and K values corresponding to the edge filters.
Once Gx(j,k) and Gy(j,k) are obtained, a motion blur factor may be finally calculated according to Equation 2.
The motion detector may determine whether or not motion blurs occur based on a received motion blur factor, thereby outputting a determination result. FIG. 3A shows a motion blurred image and an output motion blur factor, and FIG. 3B shows a non-motion blurred image and an output motion blur factor.
With reference to FIG. 4, the motion detector searches for a section satisfying a threshold set to a motion blur factor and a maintenance time to determine an image having a minimum motion blur factor as a non-motion blurred image. In case of determining a plurality of non-motion blurred images, a determination may be performed in an ascending order of motion blur factors. At this point, if a threshold value is a motion blur factor, a maintenance time may mean a threshold value during a section (time period) equal to or less than the threshold value.
If the image is determined as a non-motion blurred image, the motion detector stores the image in the stabilized image store. The stabilized image store stores latest images having no motion blur, and outputs one of the latest images stored therein when motion blur occurs in an image being monitored while the user freezes or stores the image being monitored.
FIG. 5 is a flowchart of a process for storing the non-motion blurred images in real time. After a Brightness mode (B-mode) image is obtained as shown in FIG. 3, a determination whether or not motion blur occurs in the B-mode image is performed to store the B-mode image as an image A if the B-mode image is determined as a non-motion blurred image. This process is repeated in real time and continuously performed until a freeze event is generated by the user.
FIG. 6 is a flowchart of a process for correcting a motion blurred image when events for freezing and storing an image are generated by the user. After the B-mode image is obtained as shown in FIG. 4, a determination for motion blur is performed on the B-mode image if the freeze event is generated by the user by verifying whether or not the B-mode image is frozen. At this point, if motion blur occurs in the B-mode image frozen by the user, the stored image A is provided to the user.
In accordance with the present invention, information indicating whether or not motion blur occurs in an image designated by the user may be obtained. Moreover, when a motion blurred image is corrected, it may be possible to obtain a non-motion blurred image without image distortion due to the image correction. FIG. 7 shows an image which the user wants to freeze, and FIG. 8 shows a motion blurred image by the user's mistake. As shown in FIG. 9, in accordance with the present invention, a non-motion blurred image may be provided to the user by verifying motion blur in the frozen image.
At this point, the ultrasonic apparatus of the present invention may provide the user with a variety of user interfaces (UIs). With reference to FIG. 10, a UI according to one embodiment of the present invention selects images having small motion blurs and denotes motion blur factors in the form of a bar to allow the user to select one of the images. Alternatively, a UI according to another embodiment of the present invention may receive a threshold value of a motion blur factor, which is input by the user, and the ultrasonic apparatus may determine whether or not motion blur occurs in an image based on the input threshold value. Furthermore, a UI according to still another embodiment of the present invention may automatically display an image having a minimum motion blur factor.