Feature extracting method, subject recognizing method and image processing apparatus

• US 20030095698A1
• Filed: 11/07/2002
• Published: 05/22/2003
• Est. Priority Date: 11/20/2001
• Status: Active Grant

• Current Assignee: Konica Corporation (Konica Minolta Inc.)
• Original Assignee: Konica Corporation (Konica Minolta Inc.)
• Inventors: Kawano, Tsutomu
• Granted Patent: US 7,123,761 B2
• Time in Patent Office: Days
• US Class Current: 382/132
• CPC Class Codes: G06T 2207/10116 X-ray image
• CPC Class Codes: G06T 2207/20068 Projection on vertical or horizontal image axis
• CPC Class Codes: G06T 2207/30012 Spine; Backbone
• CPC Class Codes: G06T 2207/30061 Lung
• CPC Class Codes: G06T 7/12 Edge-based segmentation

Abstract

A feature extracting method for a radiation image formed by radiation image signals each corresponding to an amount of radiation having passed through a radiographed subject, has plural different feature extracting steps, each of the plural different feature extracting steps having a respective feature extracting condition to extract a respective feature value; a feature value evaluating step of evaluating a combination of the plural different feature values; and a controlling step of selecting at least one feature extracting step from the plural different feature extracting steps based on an evaluation result by the feature value evaluating step, changing the feature extracting condition of the selected feature extracting step and conducting the selected feature extracting step so as to extract a feature value again based on the changed feature extracting condition from the radiation image.

Claims

1. A feature extracting method for a radiation image formed by radiation image signals each corresponding to an amount of radiation having passed through a radiographed subject, comprising:

plural different feature extracting steps, each of the plural different feature extracting steps having a respective feature extracting condition to extract a respective feature value so that plural different feature values are extracted from the radiation image by the plural different feature extracting steps;

a feature value evaluating step of evaluating a combination of the plural different feature values extracted by the plural different feature extracting steps; and

a controlling step of selecting at least one feature extracting step from the plural different feature extracting steps based on an evaluation result by the feature value evaluating step, changing the feature extracting condition of the selected feature extracting step and conducting the selected feature extracting step so as to extract a feature value again based on the changed feature extracting condition from the radiation image.

2. The feature extracting method of claim 1, further comprising:

an subject region extracting step of extracting an subject region representing the radiographed subject from a radiographed image region,

wherein the plural different feature values are extracted from the subject region extracted by the subject region extracting step.

3. The feature extracting method of claim 2, wherein the plural different feature extracting steps comprises an outline recognizing step of extracting a feature value based on an outline of the subject region which is obtained by investigating an outline of the subject region.

4. The feature extracting method of claim 1, wherein the plural different feature extracting steps comprises an edge pattern recognizing step of investigating signal intensity variations among neighboring pixels around an arbitrarily selected pixel on the radiation image, determining an arbitrarily selected pixel having a large signal intensity variation as an edge pixel, and extracting a feature value based on a distribution of edge pixels.

5. The feature extracting method of claim 1, wherein the plural different feature extracting steps comprises a lung field region detecting step of investigating whether or not a lung field region exists on the radiation image and extracting a feature value based on a result of the investigation.

6. The feature extracting method of claim 1, wherein when the controlling step recognizes that there is a determinant feature to specify the radiographed subject in the combination of the plural different feature values, the controlling step stops a further feature extracting step.

7. The feature extracting method of claim 1, wherein the controlling step investigates the coordination of the combination of the plural different feature values and when the controlling step judges that the combination of the plural different feature values is not coordinated, the controlling step selects a feature value to be extracted again based on the uncoordinated combination of the plural different feature values and conducts a further feature extracting step.

8. The feature extracting method of claim 7, wherein the controlling step has a list of uncoordinated combinations of plural different feature values, and

a feature value to be extracted again is predetermined for each of the uncoordinated combinations.

9. The feature extracting method of claim 1, wherein the feature extracting condition of each of the plural different feature extracting steps includes plural threshold conditions to determine a feature value, and wherein the controlling step changes the threshold condition of the selected feature extracting step and conducts the selected feature extracting step so as to extract a feature value again by using the changed threshold condition.

10. A method of recognizing a subject from a radiation image formed by radiation image signals each corresponding to an amount of radiation having passed through a radiographed subject, comprising:

plural different feature extracting steps, each of the plural different feature extracting steps having a respective feature extracting condition to extract a respective feature value so that plural different feature values are extracted from the radiation image by the plural different feature extracting steps;

a feature value evaluating step of evaluating a combination of the plural different feature values extracted by the plural different feature extracting steps;

a controlling step of selecting at least one feature extracting step from the plural different feature extracting steps based on an evaluation result by the feature value evaluating step, changing the feature extracting condition of the selected feature extracting step and conducting the selected feature extracting step so as to extract a feature value again based on the changed feature extracting condition from the radiation image; and

a recognizing step of recognizing a radiographed part of the subject on the radiation image and a radiographing orientation by using the plural different feature values.

11. The method of claim 10, wherein the plural different feature extracting steps comprises an outline recognizing step, an edge pattern recognizing step and a lung field region detecting step.

12. The method of claim 10, wherein when the controlling step recognizes that there is a determinant feature to specify the radiographed subject in the combination of the plural different feature values, the controlling step stops a further feature extracting step.

13. The method of 10, wherein the controlling step investigates the coordination of the combination of the plural different feature values and when the controlling step judges that the combination of the plural different feature values is not coordinated, the controlling step selects a feature value to be extracted again based on the uncoordinated combination of the plural different feature values and conducts a further feature extracting step.

14. A computer system for conducting a feature extracting method for a radiation image formed by radiation image signals each corresponding to an amount of radiation having passed through a radiographed subject, the computer system including a program comprising:

plural different feature extracting steps, each of the plural different feature extracting steps having a respective feature extracting condition to extract a respective feature value so that plural different feature values are extracted from the radiation image by the plural different feature extracting steps;

a feature value evaluating step of evaluating a combination of the plural different feature values extracted by the plural different feature extracting steps; and

a controlling step of selecting at least one feature extracting step from the plural different feature extracting steps based on an evaluation result by the feature value evaluating step, changing the feature extracting condition of the selected feature extracting step and conducting the selected feature extracting step so as to extract a feature value again based on the changed feature extracting condition from the radiation image.

15. The computer system of claim 14, wherein the plural different feature extracting steps comprises an outline recognizing step, an edge pattern recognizing step and a lung field region detecting step.

16. The computer system of claim 14, wherein when the controlling step recognizes that there is a determinant feature to specify the radiographed subject in the combination of the plural different feature values, the controlling step stops a further feature extracting step.

17. The computer system of claim 14, wherein the controlling step investigates the coordination of the combination of the plural different feature values and when the controlling step judges that the combination of the plural different feature values is not coordinated, the controlling step selects a feature value to be extracted again based on the uncoordinated combination of the plural different feature values and conducts a further feature extracting step.

18. An image processing apparatus for processing a radiation image formed by radiation image signals each corresponding to an amount of radiation having passed through a radiographed subject, comprising:

plural different feature extracting sections, each of the plural different feature extracting sections having a respective feature extracting condition to extract a respective feature value so that plural different feature values are extracted from the radiation image by the plural different feature extracting sections;

a feature value evaluating section to evaluate a combination of the plural different feature values extracted by the plural different feature extracting sections; and

a controlling section to select at least one feature extracting section from the plural different feature extracting sections based on an evaluation result by the feature value evaluating section, changing the feature extracting condition of the selected feature extracting section and controlling the selected feature extracting section so as to extract a feature value again based on the changed feature extracting condition from the radiation image.

19. The image processing apparatus of claim 18, further comprising:

an subject region extracting section of extracting an subject region representing the radiographed subject from a radiographed image region,

wherein the plural different feature values are extracted from the subject region extracted by the subject region extracting section.

20. The image processing apparatus of claim 18, wherein the plural different feature extracting sections comprises an outline recognizing section of extracting a feature value based on an outline of the subject region which is obtained by investigating an outline of the subject region.

21. The image processing apparatus of claim 18, wherein the plural different feature extracting sections comprises an edge pattern recognizing section of investigating signal intensity variations among neighboring pixels around an arbitrarily selected pixel on the radiation image, determining an arbitrarily selected pixel having a large signal intensity variation as an edge pixel, and extracting a feature value based on a distribution of edge pixels.

22. The image processing apparatus of claim 18, wherein the plural different feature extracting sections comprises a lung field region detecting section of investigating a presence or absence of a lung field region on the radiation image and extracting a feature value based on a result of the investigation.

23. The image processing apparatus of claim 18, wherein when the controlling section recognizes that there is a determinant feature to specify the radiographed subject in the combination of the plural different feature values, the controlling section stops further extracting a feature value.

24. The image processing apparatus of claim 18, wherein the controlling section investigates the coordination of the combination of the plural different feature values and when the controlling section judges that the combination of the plural different feature values is not coordinated, the controlling section selects a feature value to be extracted again based on the uncoordinated combination of the plural different feature values and conducts a further feature extracting step.

25. The image processing apparatus of claim 24, wherein the controlling section has a list of uncoordinated combinations of plural different feature values, and a feature value to be extracted again is predetermined for each of the uncoordinated combinations.

26. The image processing apparatus of claim 18, wherein the feature extracting condition of each of the plural different feature extracting sections includes plural threshold conditions to determine a feature value, and wherein the controlling section changes the threshold condition of the selected feature extracting section and controls the selected feature extracting section so as to extract a feature value again by using the changed threshold condition.