Color Imaging team
  Image group
  CRIStAL laboratory

Extended Outex texture classification test suites

The following classification test suites are derived from Outex color texture images. Their are motivated by the following remarks:

  • Outex images in the downloadable raster files of gray-level test suites are affected by an (undocumented) scale change of gray levels (see Figure 1), which may yield biased results with some texture descriptors. We have therefore regenerated some of the gray-level test suites from Outex original color images (see table 1) using the intensity formula given in Outex documentation: I=0.299R+0.587G+0.114B.

(a) (b)
Figure 1: Histogram of image 000000 in (a) original Outex_TC_00011 test suite and (b) Outex_TC_00011 below

 

  • Most Outex test suites contain 24 textures, which generally yields very high classification results (above 95%). We have therefore extended them to the same 68 textures as in Outex-TC-00013 (see table 1).
  • Outex test suites offer several variations of acquisition conditions (illuminant, spatial resolution, camera rotation) but no degradation of the captured images. We have therefore simulated noisy and blurred images in new degraded test suites (see table 2).

Note: Only the original test suites Outex_TC_00010—14, that use a window size of 128×128 pixels, are regenerated and/or extended below.

 

Table 1: Classification test suites with variations in acquisition conditions

Test suite ID Image type Textures Illuminants Rotations (°) Resolutions (dpi) Number of train images Number of test images Link Remarks
Outex_TC_00010-r Gray-level 24 textures Inca 00,05,10,15,30,45,60,75,90 100 480 (20×24) 3840 (8×20×24) Download Original Outex_TC_00010 regenerated from color images
Outex_TC_00010-c Color 24 textures Inca 00,05,10,15,30,45,60,75,90 100 480 (20×24) 3840 (8×20×24) Download Color counterpart of original Outex_TC_00010
Outex_TC_00011-r Gray-level 24 textures Inca 00 100,120 480 (20×24) 480 (20×24) Download Original Outex_TC_00011 regenerated from color images
Outex_TC_00012-i Gray-level 24 textures Inca, Horizon, TL84 00 100 480 (20×24) 480 (20×24) or 960 (2×20×24) Download Original Outex_TC_00012 regenerated from color images, with illuminant variations only and 3 problems (illuminant of test images: horizon, TL84, or both)
Outex_TC_00013-l Gray-level 68 textures Inca 00 100 680 (10×68) 680 (10×68) Download Gray-level version of original Outex_TC_00013
Outex_TC_00020 Gray-level 68 textures Inca 00, 05, 10, 15, 30, 45, 60, 75, 90 100 1360 (20×68) 10880 (8×20×68) Download Above Outex_TC_00010-r extended to 68 classes
Outex_TC_00021 Gray-level 68 textures Inca 00 100,120 1360 (20×68) 1360 (20×68) Download Above Outex_TC_00011-r extended to 68 classes
Outex_TC_00024 Gray-level 68 textures Inca, Horizon, TL84 00 100 1360 (20×68) 1360 (20×68) or 2720 (2×20×68) Download Above Outex_TC_00012-i extended to 68 classes
Outex_TC_00030 Color 68 textures Inca 00, 05, 10, 15, 30, 45, 60, 75, 90 100 1360 (20×68) 10880 (8×20×68) Download Color version of above Outex_TC_00020
Outex_TC_00031 Color 68 textures Inca 00 100,120 1360 (20×68) 1360 (20×68) Download Color version of above Outex_TC_00021
Outex_TC_00034 Color 68 textures Inca, Horizon, TL84 00 100 1360 (20×68) 1360 (20×68) or 2720 (2×20×68) Download Color version of above Outex_TC_00024, i.e., original Outex_TC_00014 with 3 problems

 

Table 2: Classification test suites with specific degradations of test images

  • Illuminant: Inca
  • Rotation: 00 °
  • Resolution: 100 dpi
Test suite ID Image type Textures Noise Blur Number of train images Number of test images Link Remarks
Outex_TC_00011-n Gray-level 24 textures Gaussian, σ=5 none 480 (20×24) 480 (20×24) Download Generated from above Outex_TC_00011-r
Outex_TC_00022 Gray-level 68 textures Gaussian, σ=5 none 1360 (20×68) 1360 (20×68) Download Generated from above Outex_TC_00013-l
Outex_TC_00023 Gray-level 68 textures none Gaussian, ρ=0.5 1360 (20×68) 1360 (20×68) Download Generated from above Outex_TC_00013-l. ρ: radius of decay of Gaussian filter
Outex_TC_00032 Color 68 textures Gaussian, σ=5 none 1360 (20×68) 1360 (20×68) Download Generated from original Outex_TC_00013
Outex_TC_00033 Color 68 textures none Gaussian, ρ=0.5 1360 (20×68) 1360 (20×68) Download Generated from original Outex_TC_00013