Floral Image Database
Have you ever wondered how a bee sees the world? Here we provide our best guess. We illustrate an approach that can transform a series of black and white photographs into a normal full colour photograph, a false colour image, and an array of reflectance spectra.
Feel free to examine our floral database, and don't hesitate to contact us with any questions or requests.
Vision & Colorimetry
Below we highlight a few examples from our floral image database. Each image illustrates the normal human perceived colour (left) and the bee false colour image (right). Our images are separated into categories that can be explored by clicking links (below and to the left). Choose a category and then click on any of the images to display the full image. On the full sized image, you may click the right side of the image to proceed to the next flower in that category (similarly, clicking the left side turns pages in the opposite direction). We only show 12 thumbnails below, but you can browse through more images within for each category. For more information please contact danielhanley00 -at- gmail.com
We used a series of filters to develop black
and white photographs, and then custom computer programs
to generate these full colour images.
This is similar to the experience one may
have while wearing rose coloured glasses; however, we have many
more pairs of glasses, each of a different colour. This allows us to easily calculate spectral reflectance or visual stimulation for any point
in an image, which can improve how colour data are collected and processed in various research fields.
This website achieves our primary goal to share these false colour images with the public. Next we plan to:
1) Implement these techniques with modern digital cameras synchronized to computers for real-time data collection and processing
2) Develop methods for analysing colour patterns using these multispectral images.
3) Make all methods, programs, and data freely accessible to the public and research community.
If you would like more immediate access to these data, please contact us below.
How did we colour these images?
Data aquisitionThe pictures that we present to you were all composed from photographs taken on Black and White film in a camera fitted with a broad band-pass transmitting quartz lens. With both the film and the lens, it is possible to capture reflected light from UV through the human visible spectrum to near IR. However, to understand colour, it is necessary to divide the broad spectrum into primary wavebands for insect and for human colour visions. For human colour vision, a blue, a green, and a red broad-band filters were used on the front of the camera to capture blue (B), green (G), and red (R) reflectances. For insect colour vision, the visual spectrum is shifted towards the shorter wavebands. Thus, an UV, blue, and green broad band-past filters were used. Most insects are insensitive to red. Thus, we had four colour channels captured on the film (UV, blue, green, and red). We also used intermediate broad-band pass filters to control the photography and colour renditions.
Reconstructing colourWith the series of four primary black and white pictures (as photographic negatives), we reconstructed the floral colours. The three primary reflectances in B, G, and R were combined on the computer to reconstruct floral colours as human beings see them (B + G + R in more or less equal proportions result in white; B + R result in purple to mauve; G + R result in tones of yellow; B + G result in what human being see as blue-green; if B, G, or R alone predominate, then those colours are perceived). We did exactly the same for construction of the colours and insects might perceive them, but when UV reflectance was captured, we had the computer code it B; when Blue reflectances were captured we had the computer code those G; and when Green reflectances were captured, the computer coded them R. Thus, we could construct false-colour floral images from UV though to Green reflectances and produce coloured pictures that represented UV + B + G as "insect-white"; UV + G as "insect purple"; B + G as "insect-yellow"; and the primary colours as "insect-blue" (for UV reflectances), "insect-green" (for Blue reflectances), and "insect-red" (for Yellow reflectances). Below we illustrate the process of data acquisition (step 1), colouring the layers (step 2, note the shift of the bee images into the human visual range), and then combining the photographs into a false colour image (step 3).
Image interpretationIn the pictures we provide, the pale blue flowers of flax (Linum lewisii) appear as "pale insect-green" (find these images in our database). The yellow blossoms of many composites (Asteraceae) reflect only "insect-red" signals, but if portions of the flower also reflect UV then "insect-purple" results (both colours are found on Arnica mollis, displayed above). Almost all white flowers and floral parts do not reflect UV, and so are constructed an "insect-yellow". Applying the same rules, but using the primary colours for human beings, yellow blossoms (e.g. Dasiphora fruticosa), reflecting both green and red lights, are reconstructed as yellow; those that reflect both blue and red signals (e.g. Primula parryi) are reconstructed as purple, those that reflect in all three primary wavebands (e.g. Gentiana calycosa) reconstruct as white. The accuracy of the reconstruction of the colours as human beings perceive them speaks to the general accuracy of the technique, especially as it might apply to understanding the colours of flowers and vegetation as insects might perceive them. These properties are illustrated on the right using human and bee false colour images.
Through photography, colour patterns can also be deconstructed and reconstructed and spectral reflectances can be extracted for any point in the image. Thus, patterns which are invisible to human beings (e.g. UV + G with G alone) on some yellow blossoms become evident, and those that are visible to human beings become invisible (as B with G + R for blossoms with blue peripheries and yellow centres as Eritrichum). For flowers that have red patterns, in the insect-colour scheme, they have black patterns on coloured backgrounds. The colours of floral parts also make interesting patterns: yellow anthers make for insect-red appendages within flowers (e.g. Aconitum columbianum, found in the database).
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Please use the form below to contact us with any questions about the website or how we created our floral images or reflectance spectra. We will continue to update this site with more information. Any feedback that you have would be valuable for us. For other questions or general inquiries, please contact us directly using the contact information to the right.