Image description notes:
"bird_nestwall.png": A blue-black grasssquit (Volatinia jacarina) nest deposited in the museum collection Coleção Ornitológica Marcelo Bagno, at Universidade de Brasília (catalog number COMB-N682). Image process description:  I)  a photo of the nest was taken with a white styrofoam ball (50mm in diameter) placed inside nest chamber. II) In GIMP software (Version 2.10.10), alpha channel was added (to allow transparent pixels), and the Ellipse select tool was used to select contrast of the white ball and nest wall, and then erased all background elements. III) To ensure that shadows from nest wall did not influence white ball detection, the threshold processing was also performed in GIMP. To preserve the transparent pixels from background elements, the final image must be saved as a PNG file.
"bush.JPG": The imagem comprises a vegetation section of 30x100cm. Image process description:  in one of the 100cm side of the panel of 100x100cm covered with a white cloth was placed perpendicular to the ground. A plastic canvas of 50x100cm was used to cover the vegetation along a narrow strip in front of a camera positioned on a tripod at a height of 55 cm. A photograph of the portion of standing vegetation against the white cloth was taken.
"canopy.JPG": An image of a canopy is obtained with digital photography
"chesstable.png": Drawing of a chess board
