Kyoto natural images

A set of calibrated color natural images, including three classes of cone photoreceptor responses (i.e., long (L), medium (M), and short (S) cone types) with their nonlinear transform.

Key features

color natural images, human cone photoreceptor spectral sensitivity, nonlinearity/gamma calibration, large number of samples (originally 1000x1280x3 pixels and 10 bit depth for each R G B plane, utilizing 3CCD chip).

Description

62 images of natural scenes, obtained using 3CCD digital still camera system (HC-2500, Fujifilm, Japan). Each RGB image (1000x1280 pixels, 10 bits for each R, G, B) were corrected for gamma calibration, effect of iris size, and exposure time.

The linear RGB data were transformed into LMS cone responses using 3 by 3 matrix. This matrix was derived by minimizing the square errors for 170 surface reflectance functions (Vrhel et al, 1994) rendered by 4 kinds of CIE daylight functions (D50, D55, D65, and D75), and the resulting errors were 0.23%, 0.14%, and 0.04% for L-, M-, and S-cone, respectively. Its accuracy was validated by a different set of reflectance functions (ColorCheker(R), Macbeth, U.S.A.), and the estimation errors were reasonably small (0.39%, 0.23%, and 0.03% for L-, M-, and S-cone, respectively).

The linear cone response data were further transformed with an empirical cone nonlinear function (Baylor et al., 1987)

where r_l is linear cone responses, r_nl is non-linearly transformed cone responses in the range [0,1], and the parameter k is determined so that the median of r_nl is 0.5 for each scene and for each cone-type.

Download

The dataset consists of 62 MATLAB files, each of which contains nonlinear responses of L-cone (OL), M-cone (OM), and S-cone (OS).
ftp site to download the data

If you don't need color components, we recommend to use only OL.

The .mat files of OL's are packaged in 4 gziped tar archives for your convenience:
kyo_data01.tar.gz (120mb)
kyo_data02.tar.gz (120mb)
kyo_data03.tar.gz (102mb)
kyo_data04.tar.gz (89mb)

Acknowledgment

The construction of this dataset was supported by Grant-in-Aid for Scientific Research (A)(2) from MEXT (#11309007) to Toshio Inui and by JSPS Research Fellowships for Young Scientists (#200103140) to Eizaburo Doi. We acknowledge Toshikazu Wada for his help with the camera calibration and Kyoto Botanical Gardens for assistance with natural image collection.

If you use this data set, please cite the following paper.

Doi, E., Inui, T., Lee, T.-W., Wachtler, T., & Sejnowski, T. J.
Spatiochromatic receptive field properties derived from information-theoretic analyses of cone mosaic responses to natural scenes.
Neural Computation, 2003, vol.15, pp.397-417. [pdf] [bib]

@article{doi:03,
Author = {Doi, E. and Inui, T. and Lee, T.-W. and Wachtler, T. and Sejnowski, T. J.},
Title = {Spatiochromatic receptive field properties derived from information-theoretic analyses of cone mosaic responses to natural scenes},
Journal = {Neural Computation},
Volume = {15},
Pages = {397-417},
Year = {2003}
}

If you have any questions about this dataset, please email edoi+natim at cmu.edu.