Image processing device, image processing method, and image pickup apparatus
An image processing device includes a corrector for performing an optical correction of correcting a distortion of an image by interpolating image data of the distorted picked-up image resulting from an optical characteristic of an image pickup section, and locally changing a resolution of the image; and a compressor for performing a dynamic range compression of compressing a dynamic range of the image data by extracting an illumination component from the image data based on a space frequency of the image, and compressing the extracted illumination component, wherein the compressor performs the dynamic range compression with respect to image data of an after-correction-image to be obtained after the optical correction is performed by the corrector.
1. An image processing device, comprising at least two of:
a converter for unifying multiple photoelectric conversion characteristics of image data of an image picked up by an image pickup section having multiple photoelectric conversion characteristics into a single photoelectric conversion characteristic;
a corrector for performing an optical correction of correcting a distortion of the image by interpolating the image data of the distorted picked-up image resulting from an optical characteristic of the image pickup section, and locally changing a resolution of the image; and
a compressor for performing a dynamic range compression of compressing a dynamic range of the image data by extracting an illumination component from the image data based on a space frequency of the image, and compressing the extracted illumination component, wherein
the compressor performs the dynamic range compression with respect to image data to be obtained after the optical correction is performed by the corrector, and
the converter performs a processing of unifying the photoelectric conversion characteristics with respect to image data to be obtained before the optical correction is performed by the corrector.
2. The image processing device according to claim 1 , wherein
the image processing device includes the converter, the corrector, and the compressor,
the converter performs the processing of unifying the photoelectric conversion characteristics with respect to the image data to be obtained before the optical correction is performed by the corrector, and
the compressor performs the dynamic range compression with respect to the image data to be obtained after the optical correction is performed by the corrector.
3. The image processing device according to claim 2 , wherein the corrector includes:
a coordinate storage for storing, in advance, a coordinate value in a before-correction-image to be obtained before the optical correction is performed, in correlation to each pixel in an after-correction-image to be obtained after the optical correction is performed;
a coordinate output section for sequentially outputting the coordinate value in the before-correction-image from the coordinate storage;
an image data storage for storing image data of the before-correction-image to output pixel data of a vicinity pixel located in the vicinity of a target pixel having the coordinate value outputted from the coordinate storage; and
an interpolator for calculating pixel data of the target pixel based on the pixel data of the vicinity pixel outputted from the image data storage.
4. The image processing device according to claim 3 , wherein the interpolator calculates the pixel data of the target pixel by increasing a weight to be applied to the pixel data of the vicinity pixel, as the vicinity pixel approaches the target pixel.
5. The image processing device according to claim 3 , wherein
the image data storage outputs the pixel data of the vicinity pixel by defining four pixels in the vicinity of the target pixel as the vicinity pixel, and
the interpolator calculates an average value of the pixel data of the vicinity pixels to define the average value as the pixel data of the target pixel.
6. The image processing device according to claim 2 , wherein
the image pickup section has two kinds of photoelectric conversion characteristics, one being a linear characteristic in a low luminance range with respect to an inflection point, and the other being a logarithmic characteristic in a high luminance range with respect to the inflection point, and
the converter converts the logarithmic characteristic into the linear characteristic.
7. An image processing method, comprising:
a correcting step of performing an optical correction of correcting a distortion of an image by interpolating image data of the distorted picked-up image resulting from an optical characteristic of an image pickup section, and locally changing a resolution of the image; and
a compressing step of performing a dynamic range compression of compressing a dynamic range of the image data by extracting an illumination component from the image data based on a space frequency of the image, and compressing the extracted illumination component, wherein
the compressing step is performed after the correcting step.
8. An image pickup apparatus comprising the image processing device of claim 1 .
9. An image processing device, comprising:
a correction means for performing an optical correction of correcting a distortion of an image by interpolating the distorted picked-up image resulting from an optical characteristic of an image pickup means, and locally changing a resolution of the image; and
a compression means for performing a dynamic range compression of compressing a dynamic range of the image by extracting an illumination component from the image based on a space frequency of the image, and compressing the extracted illumination component, wherein
the compression means performs the dynamic range compression with respect to the image to be obtained after the optical correction is performed by the correction means.