Image processing apparatus and method
When a blurring process is performed for an image, noise is reduced according to the characteristics of a blurring process filter in a target region of the blurring process. Accordingly, a difference occurs in noise amount with a non-target region of the blurring process. In view of such situations, an image processing apparatus according to an embodiment of the present invention adds noise to the blurring target region. Accordingly, the difference in noise amount can be reduced, and a blurring-emphasized image with a natural texture can be created. Furthermore, the image processing apparatus according to the embodiment of the present invention determines the noise amount according to the blurring amount by the blurring process filter while considering that, the larger the blurring amount is, the more greatly the noise is reduced by the blurring process, and adds the noise.
1. An image processing apparatus, comprising:
a reference image acquisition device which acquires a reference image of a subject;
a blurring amount setting device which sets a blurring amount for the reference image;
a blurred image creating device which applies a blurring process filter to the acquired reference image by the set blurring amount to generate a blurred image, the blurred image being created whose noise is reduced depending on characteristics of the blurring process filter;
a difference calculation device which calculates a difference value between the acquired reference image and the generated blurred image, for the acquired reference image; and
a combined image generation device which weights and adds the reference image and the blurred image, according to the calculated difference value, to generate a combined image.
2. The image processing apparatus according to claim 1 ,
wherein if the calculated difference value is within a prescribed range,
the combined image generation device sets a weight such that, the smaller the difference value is, the larger the weight on the reference image is and the smaller the weight on the blurred image is, and
sets a weight such that, the larger the difference value is, the smaller the weight on the reference image is and the larger the weight on the blurred image is.
3. The image processing apparatus according to claim 1 , further comprising:
a noise amount determination device which determines a noise amount according to imaging sensitivity of the reference image; and
a noise addition device which adds noise of the amount determined according to the imaging sensitivity.
4. The image processing apparatus according to claim 2 , further comprising:
a noise amount determination device which determines a noise amount according to imaging sensitivity of the reference image; and
a noise addition device which adds noise of the amount determined according to the imaging sensitivity.
5. An image processing method, comprising:
a reference image acquisition step of acquiring a reference image of a subject;
a blurring amount setting step of setting a blurring amount for the reference image;
a blurred image creating step of applying a blurring process filter to the acquired reference image by the set blurring amount to generate a blurred image, the blurred image being created whose noise is reduced depending on characteristics of the blurring process filter;
a difference calculation step of calculating a difference value between the acquired reference image and the generated blurred image, for the acquired reference image; and
a combined image generation step of weighting and adding the reference image and the blurred image, according to the calculated difference value, to generate a combined image.
6. The image processing method according to claim 5 ,
wherein if the calculated difference value is within a prescribed range,
the combined image generation step sets a weight such that, the smaller the difference value is, the larger the weight on the reference image is and the smaller the weight on the blurred image is, and
sets a weight such that, the larger the difference value is, the smaller the weight on the reference image is and the larger the weight on the blurred image is.
7. The image processing method according to claim 5 , further comprising:
a noise amount determination step of determining a noise amount according to image sensitivity of the reference image; and
a noise addition step of adding noise of the amount determined according to the imaging sensitivity.
8. The image processing method according to claim 6 , further comprising:
a noise amount determination step of determining a noise amount according to image sensitivity of the reference image; and
a noise addition step of adding noise of the amount determined according to the imaging sensitivity.