Image processing apparatus, image processing method, and image processing program

Abstract

An image processing apparatus includes the following elements. An image data obtaining unit obtains image data. A sampling unit samples the image data. A statistic value determining unit determines a statistic value based on statistic information in a histogram with respect to a grayscale value of image data that is obtained by performing rough quantization and linear interpolation on the sampled image data. A correction-amount determining unit determines a correction amount to be used for image processing based on the statistic value. An image processing unit performs the image processing according to the correction amount.

Description

BACKGROUND [0001] 1. Technical Field [0002] The present invention relates to techniques for performing image processing on image data using sampled image data. [0003] 2. Related Art [0004] There have been proposed techniques for associating image data with image processing control information containing image processing conditions of the image data, as disclosed in, for example, JP-A-2003-52002. The image processing control information is configured so that, depending on the combination of the image generating device, e.g., a digital still camera, and the output device, e.g., a printer, the quality of images output from the output device can be improved. By performing image processing (image-quality adjustment) on the image data according to the image processing control information (image processing conditions) associated with the image data, an image processing apparatus obtains output images reflecting the image output characteristics of the output device. In the image processing ...

AI Technical Summary

Benefits of technology

[0006] An advantage of the invention is that, even in the case of low-resolution sampled image data, high-accuracy statistic values are determined to derive a correction amount appropriate for image processing.

[0007] According to an aspect of the invention, image processing apparatus includes the following elements. An image data obtaining unit obtains image data. A sampling unit samples the image data. A statistic value determining unit determines a statistic value based on statistic information in a histogram with respect to a grayscale value of image data that is obtained by performing rough quantization and linear interpolation on the sampled image data. A correction-amount determining unit determines a correction amount to be used for image processing based on the statistic value. An image processing unit performs the image processing according to the correction amount.

[0008] The image processing apparatus is incorporated in, for example, a portable device, a display device, a color printer, or the like, and performs image processing on image data obtained from the outside based on statistic values of the image data. The image processing apparatus samples the image data at a low resolution, performs rough quantization on the sampled image data, and performs linear interpolation of the number of pixels, thereby generating a histogram. The image processing apparatus determines a correction amount based on statistic values that are determined from statistic information in the generated histogram, and performs image processing on the image data. Thus, in the case of low-resolution sampled image data, the accuracy of the statistic values is high and the correction amount can correctly be derived.

[0009] According to another aspect of the invention, an image processing method includes obtaining image data, sampling the image data, determining a statistic value based on statistic information in a histogram with respect to a grayscale value of image data that is obtained by performing rough quantization and linear interpolation on the sampled image data, determining a correction amount to be used for image processing based on the statistic value, and performing the image processing according to the correction amount.

[0010] According to another aspect of the invention, an image processing program executed by an image processing apparatus including a control circuit causes the image processing apparatus to function as an image data obtaining unit that obtains image data, a sampling unit that samples the image data, a statistic value determining unit that determines a statistic value based on statistic information in a histogram with respect to a grayscale value of image data that is obtained by performing rough quantization and linear interpolation on the sampled image data, a correction-amount determining unit that determines a correction amount to be used for image processing based on the statistic value, and an image processing unit that performs the image processing based on the correction amount.

[0011] The image processing method and the image processing program also allow a high-accuracy statistic value and a precise correction amount to be derived in the case of low-resolution sampled image data.

Problems solved by technology

In the related art, however, an operation of determining statistic values of image data places a large load on a control circuit.

If the image data is sampled at a low resolution to determine the statistic values in order to reduce the load on the control circuit, the resolution of the sampled image data is low, and the accuracy of the statistic values is also low.

It is therefore difficult to correctly derive the correction amount.

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