Image detection device and image detection method

1. An image detection device detecting a specific image to be searched for from an image, the device comprising:

a size changing means for changing a size of an original image according to a set scaling factor;

a detection means for detecting the specific image to be searched for within a detectable size range of the image detection device from the image, the size of which has been changed by the size changing means;

means for determining an absent area where another specific image cannot exist on the basis of the detected specific image, when the specific image to be searched for is detected by the detection means,

a change means for changing the scaling factor; and

a control means for performing control so as to make the processing by the size changing means and the processing by the detection means to be carried out again using the scaling factor changed by the change means,

wherein the control means excludes a part corresponding to the absent area from an object to be detected by the detection means, when making the processing by the size changing means and the processing by the detection means to be carried out again using the changed scaling factor.

2. The image detection device according to claim 1 , wherein the control means

determines whether another specific image which is not the specific image having been detected by the detection means can exist or not within the original image,

when determining that another specific image can exist, performs the control so as to make the processing by the size changing means and the processing by the detection means to be carried out again using the scaling factor changed by the change means, and

when determining that another specific image can not exist, performs the control so as not to make the processing by the size changing means and the processing by the detection means to be carried out again.

3. The image detection device according to claim 2 , further comprising

means for determining an absent area where another specific image cannot exist on the basis of the detected specific image, when the specific image to be searched for is detected by the detection means,

wherein the control means

judges whether a ratio of a sum total of the calculated absent area to the original image is larger than a predetermined ratio, and

when judging that the ratio is smaller than the predetermined ratio, determines that the another specific image can exist, and performs the control so as to make the processing by the size changing means and the processing by the detection means to be carried out again using the scaling factor changed by the change means.

4. The image detection device according to claim 3 , wherein the control means, when judging that the absent area has the ratio larger than the predetermined ratio, determines that the another specific image does not exist, and performs the control so as not to make the processing by the size changing means and the processing by the detection means to be carried out again.

5. The image detection device according to claim 2 , wherein the control means, when judging that the scaling factor after changed by the change means exceeds a predetermined criterion, determines that the another specific image does not exist, and performs the control so as not to make the processing by the size changing means and the processing by the detection means to be carried out again.

6. The image detection device according to claim 5 , wherein the control means determines that the specific image to be searched for does not exist within the original image, when it judges that the scaling factor after changed by the change means exceeds the predetermined criterion and also none of the specific image to be searched for has not been detected.

7. The image detection device according to claim 1 , wherein the control means excludes the part corresponding to the absent area in the original image from the object to be detected by the detection means by painting out an image part corresponding to the absent area in a predetermined color.

8. The image detection device according to claim 1 , wherein the control means retains coordinate information of an image part corresponding to the absent area in the original image in a memory and excludes the part corresponding to the absent area from the object to be detected by the detection means according to the coordinate information.

9. The image detection device according to claim 1 , wherein the means for determining the absent area determines the absent area according to a shape of the detected specific image.

10. The image detection device according to claim 1 , further comprising means for setting an initial value of the scaling factor.

11. The image detection device according to claim 1 , wherein the change means changes the scaling factor into a scaling factor larger than a previous one.

12. The image detection device according to claim 1 , wherein the specific image to be searched for is a number plate.

13. An image detection method detecting a specific image to be searched for from an image, the method comprising the steps of:

changing a size of an original image according to a set scaling factor;

detecting the specific image to be searched for from the image, the size of which has been changed by the size changing step;

determining an absent area where another specific image cannot exist on the basis of the detected specific image, when the specific image to be searched for is detected in the detecting step,

changing the scaling factor; and

performing control so as to make the size changing step and the detecting step to be carried out again using the scaling factor changed by the changing step,

wherein the step of performing control includes excluding a part corresponding to the absent area from an object to be detected in the detecting step, when making the processing in the size changing step and the processing in the detecting step to be carried out again using the changed scaling factor.

14. The image detection method according to claim 13 , wherein the step of performing control

includes determining whether another specific image which is not the specific image having been detected in the detecting step can exist or not within the original image,

when determining that another specific image can exist, includes performing the control so as to make the size changing step and the detecting step to be carried out again using the scaling factor changed in the changing step, and

when determining that another specific image can not exist, includes performing the control so as not to make the size changing step and the detecting step to be carried out again.

15. A non-transitory computer-readable storage medium, storing a computer program therein for causing a computer to execute the method according to claim 13 .

16. An image detection device detecting a specific image to be searched for from an image, the device comprising:

a size changing means for changing a size of an original image according to a set scaling factor;

a detection means for detecting the specific image to be searched for within a detectable size range of the image detection device from the image, the size of which has been changed by the size changing means;

means for determining a peripheral area of the detected specific image as an absent area where another specific image cannot exist;

a change means for changing the scaling factor; and

a control means for performing control so as to make the processing by the size changing means and the processing by the detection means to be carried out again using the scaling factor changed by the change means,

wherein the control means excludes a part corresponding to the absent area from an object to be detected by the detection means, when making the processing by the size changing means and the processing by the detection means to be carried out again using the changed scaling factor.

17. The image detection device according to claim 16 , wherein the control means, when judging that the scaling factor after changed by the change means exceeds a predetermined criterion, determines that the another specific image does not exist, and performs the control so as not to make the processing by the size changing means and the processing by the detection means to be carried out again.

18. The image detection device according to claim 16 , wherein the control means excludes the part corresponding to the absent area in the original image from the object to be detected by the detection means by painting out an image part corresponding to the absent area in a predetermined color.

19. The image detection device according to claim 16 , wherein the control means retains coordinate information of an image part corresponding to the absent area in the original image in a memory and excludes the part corresponding to the absent area from the object to be detected by the detection means according to the coordinate information.

20. The image detection device according to claim 16 , wherein the means for determining the absent area determines the absent area according to a shape of the detected specific image.

21. An image detection method detecting a specific image to be searched for from an image, the method comprising the steps of:

changing a size of an original image according to a set scaling factor;

detecting the specific image to be searched for within a detectable size range of the image detection device from the image, the size of which has been changed by the size changing step;

determining a peripheral area of the detected specific image as an absent area where another specific image cannot exist;

changing the scaling factor; and

performing control so as to make the size changing step and the detection step to be carried out again using the scaling factor changed by the change step,

wherein the step of performing control includes excluding a part corresponding to the absent area from an object to be detected by the detection step, when making the size changing step and the detection step to be carried out again using the changed scaling factor.

22. The image detection method according to claim 21 , wherein the step of performing control, when judging that the scaling factor after changed by the change step exceeds a predetermined criterion, includes determining that the another specific image does not exist, and performing the control so as not to make the size changing step and the detection step to be carried out again.

23. The image detection method according to claim 21 , wherein the step of performing control includes excluding the part corresponding to the absent area in the original image from the object to be detected by the detection step by painting out an image part corresponding to the absent area in a predetermined color.

24. The image detection method according to claim 21 , wherein the step of performing control includes retaining coordinate information of an image part corresponding to the absent area in the original image in a memory and excludes the part corresponding to the absent area from the object to be detected by the detection step according to the coordinate information.

25. The image detection device according to claim 21 , wherein the determining step includes determining the absent area according to a shape of the detected specific image.

26. A non-transitory computer-readable storage medium, storing a computer program therein for causing a computer to execute an image detection method detecting a specific image to be searched for from an image, the method comprising the steps of:

changing a size of an original image according to a set scaling factor;

detecting the specific image to be searched for within a detectable size range of the image detection device from the image, the size of which has been changed by the size changing step;

determining a peripheral area of the detected specific image as an absent area where another specific image cannot exist;

changing the scaling factor; and

performing control so as to make the size changing step and the detection step to be carried out again using the scaling factor changed by the change step,

wherein the step of performing control includes excluding a part corresponding to the absent area from an object to be detected by the detection step, when making the size changing step and the detection step to be carried out again using the changed scaling factor.

27. The non-transitory computer-readable storage medium according to claim 26 , wherein the step of performing control, when judging that the scaling factor after changed by the change step exceeds a predetermined criterion, includes determining that the another specific image does not exist, and performing the control so as not to make the size changing step and the detection step to be carried out again.

28. The non-transitory computer-readable storage medium according to claim 26 , wherein the step of performing control includes excluding the part corresponding to the absent area in the original image from the object to be detected by the detection step by painting out an image part corresponding to the absent area in a predetermined color.

29. The non-transitory computer-readable storage medium according to claim 26 , wherein the step of performing control includes retaining coordinate information of an image part corresponding to the absent area in the original image in a memory and excludes the part corresponding to the absent area from the object to be detected by the detection step according to the coordinate information.

30. The non-transitory computer-readable storage medium according to claim 26 , wherein the determining step includes determining the absent area according to a shape of the detected specific image.

31. An image detection device detecting a specific image to be searched for from an image, the device comprising:

a size changing means for changing a size of an original image according to a set scaling factor;

a detection means for detecting the specific image to be searched for within a detectable size range of the image detection device from the image, the size of which has been changed by the size changing means;

a change means for changing the scaling factor; and

a control means for performing control so as to make the processing by the size changing means and the processing by the detection means to be carried out again using the scaling factor changed by the change means,

wherein the control means

determines whether another specific image which is not the specific image having been detected by the detection means can exist or not within the original image,

when determining that another specific image can exist, performs the control so as to make the processing by the size changing means and the processing by the detection means to be carried out again using the scaling factor changed by the change means, and

when determining that another specific image can not exist, performs the control so as not to make the processing by the size changing means and the processing by the detection means to be carried out again.

32. An image detection method detecting a specific image to be searched for from an image, the method comprising the steps of:

changing a size of an original image according to a set scaling factor;

detecting the specific image to be searched for within a detectable size range of the image detection device from the image, the size of which has been changed by the size changing step;

changing the scaling factor; and

performing control so as to make the size changing step and the detecting step to be carried out again using the scaling factor changed by the change step,

wherein the step of performing control

includes determining whether another specific image which is not the specific image having been detected by the detection step can exist or not within the original image,

when determining that another specific image can exist, includes performing the control so as to make the size changing step and the detecting step to be carried out again using the scaling factor changed in the changing step, and

when determining that another specific image can not exist, includes performing the control so as not to make the size changing step and the detecting step to be carried out again.

33. A non-transitory computer-readable storage medium, storing a computer program therein for causing a computer to execute an image detection method detecting a specific image to be searched for from an image, the method comprising the steps of:

changing a size of an original image according to a set scaling factor;

detecting the specific image to be searched for within a detectable size range of the image detection device from the image, the size of which has been changed by the size changing step;

changing the scaling factor; and

performing control so as to make the size changing step and the detecting step to be carried out again using the scaling factor changed by the change step,

wherein the step of performing control

determines whether another specific image which is not the specific image having been detected by the detection step can exist or not within the original image,

when determining that another specific image can exist, performs the control so as to make the size changing step and the detecting step to be carried out again using the scaling factor changed in the changing step, and

when determining that another specific image can not exist, performs the control so as not to make the size changing step and the detecting step to be carried out again.