Image processing system, image processing apparatus, and non-transitory computer readable medium

1. An image processing apparatus comprising

a processor configured to:

extract a component related to luminance of each of a sample image and a processing target image that is to undergo image processing to match an impression of the processing target image to an impression of the sample image,

extract a feature value of the processing target image by weighting a pixel value of each pixel forming the processing target image with a weight value responsive to the component related to the luminance in the processing target image,

extract a feature value of the sample image by weighting a pixel value of each pixel forming the sample image with a weight value responsive to the component related to the luminance in the sample image, and

make adjustment to match the feature value of the processing target image to the feature value of the sample image.

2. The image processing apparatus according to claim 1 , wherein the processor is configured to:

calculate as the feature value of the processing target image a mean and a dispersion of the pixel value of each pixel forming the processing target image, and

calculate as the feature value of the sample image a mean and a dispersion of the pixel value of each pixel forming the sample image.

3. The image processing apparatus according to claim 2 , wherein the processor is configured to:

in calculating the feature value of the processing target image:

calculate as the mean a weighted mean that is determined by weighting the pixel value of each pixel forming the processing target image with the weight value responsive to the component related to the luminance in the processing target image, and

calculate as the dispersion a standard deviation that is determined by using the weighted mean after weighting the pixel value of each pixel forming the processing target image with the weight value responsive to the component related to the luminance in the processing target image,

in calculating the feature value of the sample image:

calculate as the mean a weighted mean that is determined by weighting the pixel value of each pixel forming the sample image with the weight value responsive to the component related to the luminance in the sample image, and

calculate as the dispersion a standard deviation that is determined by using the weighted mean after weighting the pixel value of each pixel forming the sample image with the weight value responsive to the component related to the luminance in the sample image.

4. The image processing apparatus according to claim 1 , wherein the processor is configured to make adjustment to match the feature value of the processing target image to the feature value of the sample image by performing alpha blending through weighting the pixel value of each pixel forming the processing target image with the weight value responsive to the component related to the luminance in the processing target image.

5. The image processing apparatus according to claim 1 , wherein the processor is configured to:

set the weight value responsive to the component related to the luminance in the processing target image such that the weight value has a linearly proportional relationship with the component related to the luminance in the processing target image, and

set the weight value responsive to the component related to the luminance in the sample image such that the weight value has a linearly proportional relationship with the component related to the luminance in the sample image.

6. The image processing apparatus according to claim 1 , wherein the processor is configured to:

set the weight value responsive to the component related to the luminance in the processing target image to be the same as a value of the component related to the luminance in the processing target image, and

set the weight value responsive to the component related to the luminance in the sample image to be the same as a value of the component related to the luminance in the sample image.

7. The image processing apparatus according to claim 1 , wherein the processor is configured to:

set the weight value responsive to the component related to the luminance in the processing target image such that the weight value has a monotonically increasing non-linear function relationship with the component related to the luminance in the processing target image, and

set the weight value responsive to the component related to the luminance in the sample image such that the weight value has a monotonically increasing non-linear relationship with the component related to the luminance in the sample image.

8. The image processing apparatus according to claim 1 , wherein the processor is configured to modify the weight value responsive to the component related to the luminance in the sample image in response to a scene of the sample image.

9. The image processing apparatus according to claim 8 , wherein the processor is configured to set the weight value responsive to the component related to the luminance in the sample image, for the sample image being a night view, such that the weight value has a monotonically decreasing relationship with the component related to the luminance in the sample image.

10. The image processing apparatus according to claim 9 , wherein the processor is configured to set the weight value responsive to the component related to the luminance in the sample image, for the sample image not being the night view, such that the weight value has a monotonically increasing relationship with the component related to the luminance in the sample image.

11. The image processing apparatus according to claim 1 , wherein the processor is configured to correct at least one of the component related to the luminance in the processing target image and the component related to the luminance in the sample image.

12. The image processing apparatus according to claim 11 , wherein the processor is configured to adjust a degree of the image processing by correcting at least one of the component related to the luminance in the processing target image and the component related to the luminance in the sample image.

13. An image processing system comprising:

a display; and

an image processing apparatus that performs image processing on a processing target image displayed on the display,

wherein the image processing apparatus includes a processor configured to:

extract a component related to luminance of each of a sample image and a processing target image that is to undergo the image processing to match an impression of the processing target image to an impression of the sample image,

extract a feature value of the processing target image by weighting a pixel value of each pixel forming the processing target image with a weight value responsive to the component related to the luminance in the processing target image,

extract a feature value of the sample image by weighting a pixel value of each pixel forming the sample image with a weight value responsive to the component related to the luminance in the sample image, and

make adjustment to match the feature value of the processing target image to the feature value of the sample image.

14. A non-transitory computer readable medium storing a program causing a computer to execute a process for processing an image,

the process comprising:

extracting a component related to luminance of each of a sample image and a processing target image that is to undergo image processing to match an impression of the processing target image to an impression of the sample image,

extracting a feature value of the processing target image by weighting a pixel value of each pixel forming the processing target image with a weight value responsive to the component related to the luminance in the processing target image,

extracting a feature value of the sample image by weighting a pixel value of each pixel forming the sample image with a weight value responsive to the component related to the luminance in the sample image, and

making adjustment to match the feature value of the processing target image to the feature value of the sample image.