Ultrasonic image processing apparatus, ultrasonic image processing method and ultrasonic image processing program

1. An ultrasonic image processing apparatus for processing a plurality of signals obtained by scanning an object to be inspected with an ultrasonic beam and respectively representing pixel values of a plurality of pixels within an ultrasonic image, said apparatus comprising:

a morphology processing unit for processing the plurality of signals to reduce speckles appearing in the ultrasonic image; and

a digital scan converter for converting a scan format of the plurality of signals processed by said morphology processing unit;

wherein said morphology processing unit performs first signal processing on the plurality of signals while moving a mask area determined based on a structure element in morphology processing, said first signal processing including multiplying pixel values of a plurality of pixels within the mask area by a first group of weighting factors set depending on positions within the mask area, respectively, and converting a pixel value at a center of the mask area into a maximum value of the pixel values multiplied by the first group of weighting factors, and performs second signal processing on the plurality of signals subjected to the first signal processing while moving a mask area determined based on a structure element in morphology processing, said second signal processing including multiplying pixel values of a plurality of pixels within the mask area by a second group of weighting factors set depending on positions within the mask area, respectively, and converting a pixel value at a center of the mask area into a minimum value of the pixel values multiplied by the second group of weighting factors; and

wherein said first and second groups of weighting factors are set such that a value obtained by multiplying corresponding factors within the mask area in said first and second groups together becomes 1.

2. The ultrasonic image processing apparatus according to claim 1 , wherein:

said first group of weighting factors are set smaller according as the positions are apart from the center of the mask area; and

said second group of weighting factors are set larger according as the positions are apart from the center of the mask area.

3. The ultrasonic image processing apparatus according to claim 1 , wherein said first and second groups of weighting factors are set based on a frequency of ultrasonic waves to be transmitted.

4. The ultrasonic image processing apparatus according to claim 1 , wherein said first and second groups of weighting factors are set based on a depth of the object represented in the ultrasonic image.

5. The ultrasonic image processing apparatus according to claim 1 , wherein said first and second groups of weighting factors are set based on a target part of observation.

6. The ultrasonic image processing apparatus according to claim 1 , wherein said plurality of signals are obtained by scanning the object by using an ultrasonic endoscope being inserted into the object.

7. The ultrasonic image processing apparatus according to claim 1 , further comprising:

a switch for switching whether reduction of speckles by said morphology processing unit is performed or not based on information inputted by a user.

8. An ultrasonic image processing method of processing a plurality of signals obtained by scanning an object to be inspected with an ultrasonic beam and respectively representing pixel values of a plurality of pixels within an ultrasonic image, said method comprising the steps of:

(a) processing the plurality of signals to reduce speckles appearing in the ultrasonic image; and

(b) converting a scan format of the plurality of signals processed at step (a);

wherein step (a) includes (i) performing first signal processing on the plurality of signals while moving a mask area determined based on a structure element in morphology processing, said first signal processing including multiplying pixel values of a plurality of pixels within the mask area by a first group of weighting factors set depending on positions within the mask area, respectively, and converting a pixel value at a center of the mask area into a maximum value of the pixel values multiplied by the first group of weighting factors, and (ii) performing second signal processing on the plurality of signals subjected to the first signal processing while moving a mask area determined based on a structure element in morphology processing, said second signal processing including multiplying pixel values of a plurality of pixels within the mask area by a second group of weighting factors set depending on positions within the mask area, respectively, and converting a pixel value at a center of the mask area into a minimum value of the pixel values multiplied by the second group of weighting factors; and

wherein said first and second groups of weighting factors are set such that a value obtained by multiplying corresponding factors within the mask area in said first and second groups together becomes 1.

9. The ultrasonic image processing method according to claim 8 , wherein:

said first group of weighting factors are set smaller according as the positions are apart from the center of the mask area; and

said second group of weighting factors are set larger according as the positions are apart from the center of the mask area.

10. The ultrasonic image processing method according to claim 8 , wherein said first and second groups of weighting factors are set based on a frequency of ultrasonic waves to be transmitted.

11. The ultrasonic image processing method according to claim 8 , wherein said first and second groups of weighting factors are set based on a depth of the object represented in the ultrasonic image.

12. The ultrasonic image processing method according to claim 8 , wherein said first and second groups of weighting factors are set based on a target part of observation.

13. An ultrasonic image processing program, embodied in non-transitory form on a computer readable medium, for processing a plurality of signals obtained by scanning an object to be inspected with an ultrasonic beam and respectively representing pixel values of a plurality of pixels within an ultrasonic image, said program allowing a CPU to execute the procedures of:

(a) processing the plurality of signals to reduce speckles appearing in the ultrasonic image; and

(b) converting a scan format of the plurality of signals processed at procedure (a);

wherein procedure (a) includes (i) performing first signal processing on the plurality of signals while moving a mask area determined based on a structure element in morphology processing, said first signal processing including multiplying pixel values of a plurality of pixels within the mask area by a first group of weighting factors set depending on positions within the mask area, respectively, and converting a pixel value at a center of the mask area into a maximum value of the pixel values multiplied by the first group of weighting factors, and (ii) performing second signal processing on the plurality of signals subjected to the first signal processing while moving a mask area determined based on a structure element in morphology processing, said second signal processing including multiplying pixel values of a plurality of pixels within the mask area by a second group of weighting factors set depending on positions within the mask area, respectively, and converting a pixel value at a center of the mask area into a minimum value of the pixel values multiplied by the second group of weighting factors; and

wherein said first and second groups of weighting factors are set such that a value obtained by multiplying corresponding factors within the mask area in said first and second groups together becomes 1.

14. The ultrasonic image processing program according to claim 13 , wherein:

said first group of weighting factors are set smaller according as the positions are apart from the center of the mask area; and

said second group of weighting factors are set larger according as the positions are apart from the center of the mask area.

15. The ultrasonic image processing program according to claim 13 , wherein said first and second groups of weighting factors are set based on a frequency of ultrasonic waves to be transmitted.

16. The ultrasonic image processing program according to claim 13 , wherein said first and second groups of weighting factors are set based on a depth of the object represented in the ultrasonic image.

17. The ultrasonic image processing program according to claim 13 , wherein said first and second groups of weighting factors are set based on a target part of observation.