Image processing apparatus, filter acquisition apparatus, image processing method, filter acquisition method, program, and recording medium

Patent metadata

Field	Value
Publication number	US-10049438-B2
Application number	US-201715462379-A
Country	US
Kind code	B2
Filing date	Mar 17, 2017
Priority date	Sep 30, 2014
Publication date	Aug 14, 2018
Grant date	Aug 14, 2018

Abstract

Further, there are provided a filter acquisition apparatus, a filter acquisition method, a program, and a recording medium, capable of acquiring a filter which is suitably usable in such a filtering process. An image processing apparatus 35 includes a filtering process unit 41 that performs an image filtering process that has a plurality of times of filtering processes. The filtering process unit 41 applies a filter to processing target data to acquire filter application process data, applies a gain to the filter application process data to acquire gain application process data, in each filtering process. In each filtering process, the gain applied to the filter application process data is acquired based on a target frequency characteristic of the image filtering process.

First claim

What is claimed is:

1. An image processing apparatus comprising:
a filtering process circuit that performs an image filtering process that includes a plurality of times of filtering processes with respect to original image data to acquire processed image data,
wherein in each of the plurality of times of filtering processes, the filtering process circuit applies a filter to processing target data to acquire filter application process data, applies a gain to the filter application process data to acquire gain application process data, and acquires filtering process data from the gain application process data, and
wherein in each of the plurality of times of filtering processes, the gain applied to the filter application process data is acquired based on a target frequency characteristic of the image filtering process,
wherein the gain is acquired by fitting a frequency characteristic of the image filtering process to the target frequency characteristic of the image filtering process using a least squares method based on each frequency characteristic of the plurality of times of filtering processes,
wherein weighting is performed based on a frequency in the least squares method, and
wherein the weight in the least squares method is determined according to a pixel position in the original image data,
wherein the pixel position is a prioritized pixel position in the original image data and the prioritized pixel position is determined according to a type of an imaging device or a usage of the original image data.

2. The image processing apparatus according to claim 1 ,
wherein the target frequency characteristic of the image filtering process is a frequency characteristic based on an optical characteristic.

3. The image processing apparatus according to claim 1 , further comprising:
a gain candidate data storage circuit that stores gain table information obtained by associating candidate data of the gain applied to the filter application process data with gain selection conditions, in each of the plurality of times of filtering processes; and
a gain specifying circuit that specifies, with reference to the gain table information, the candidate data associated with the gain selection conditions relating to the target frequency characteristic of the image filtering process as the gain applied to the filter application process data in each of the plurality of times of filtering processes,
wherein the filtering process circuit applies the gain specified by the gain specifying circuit to the filter application process data to acquire the gain application process data in each of the plurality of times of filtering processes.

4. The image processing apparatus according to claim 1 , further comprising:
a gain acquisition circuit that acquires data indicating gain selection conditions relating to the target frequency characteristic of the image filtering process, specifies the target frequency characteristic of the image filtering process based on the data indicating the gain selection conditions, and acquires the gain applied to the filter application process data in each of the plurality of times of filtering processes based on the specified target frequency characteristic.

5. The image processing apparatus according to claim 1 ,
wherein a weight in a low-frequency band is set to be larger than a weight in a high-frequency band in the least squares method.

6. The image processing apparatus according to claim 1 ,
wherein a weight in a high-frequency band is set to be larger than a weight in a low-frequency band according to an imaging condition when the original image data is acquired, in the least squares method.

7. The image processing apparatus according to claim 1 ,
wherein a weight in a high-frequency band is large at a pixel position which is equal to or shorter than a first distance from a center of an image of the original image data, compared with a pixel position which is more distant than the first distance from the center of the image of the original image data, in the least squares method.

8. The image processing apparatus according to claim 1 ,
wherein a weight in a low-frequency band is large at a pixel position which is more distant than a second distance from a center of an image of the original image data, compared with a pixel position which is equal to or shorter than the second distance from the center of the image of the original image data, in the least squares method.

9. The image processing apparatus according to claim 1 ,
wherein the filtering process circuit uses a filter that makes the filtering process data equal to the processing target data in each of the plurality of times of filtering processes at a frequency where a ratio of the processed image data to the original image data is smaller than 1 in the target frequency characteristic of the image filtering process.

10. The image processing apparatus according to claim 1 ,
wherein the filtering process circuit acquires the filter application process data using a filter determined according to a characteristic of an optical system used when the original image data is acquired through imaging, in at least any one filtering process among the plurality of times of filtering processes.

11. The image processing apparatus according to claim 10 ,
wherein the filter determined according to the characteristic of the optical system is a filter determined based on a point spread function of the optical system.

12. The image processing apparatus according to claim 1 ,
wherein the filtering process circuit acquires the filter application process data using a filter determined irrespectively of a characteristic of an optical system used when the original image data is acquired through imaging, in at least any one filtering process among the plurality of times of filtering processes.

13. The image processing apparatus according to claim 12 ,
wherein the filter determined irrespectively of the characteristic of the optical system is a contour emphasis filter.

14. The image processing apparatus according to claim 1 ,
wherein the filtering process circuit acquires the filter application process data using a filter having a frequency characteristic according to a pixel position in the processing target data, in at least any one filtering process among the plurality of times of filtering processes.

15. The image processing apparatus according to claim 1 ,
wherein the plurality of times of filtering processes include at least a first filtering process and a second filtering process, and
wherein the filtering process circuit uses the filtering process data acquired in the first filtering process as the processing target data in the second filtering process.

16. The image processing apparatus according to claim 1 ,
wherein the plurality of times of filtering processes include at least a first filtering process and a second filtering process, and
wherein the filtering process circuit uses the same data in the first filtering process and the second filtering process as the processing target data, and acquires the processed image data based on the filtering process data acquired in the first filtering process and the filtering process data acquired in the second filtering process.

17. The image processing apparatus according to claim 1 ,
wherein the plurality of times of filtering processes include at least a first filtering process and a second filtering process, and
wherein the filtering process circuit includes
a first filter application circuit that applies a filter for the first filtering

Assignees

• Fujifilm Corp

Inventors

• Naruse Yousuke
• Hayashi Kenkichi

Classifications

• H04N23/60

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• H04N1/00

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• G06T5/20 Primary

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