High Dynamic Range Image
- Traditional image formats can only represent a limited range of intensity values for each pixel (most commonly 0 to 255 for each of the red, green and blue channels). This is sufficient for representing an image to be displayed on a computer screen, but does not allow the full range of light intensity which is present in the real world to be represented. High dynamic range image formats allow a much greater range of intensity values by using floating point values. It is then possible to represent images which contain the sort of variation in intensity which is found in the real world, without loss of precision. In order to display such images on current computer screens some form of tone mapping would be used. Apart from the advantage of being able to preserve the full intensity range until the point of display, the ability to store very high intensity values in an image format also allows such images to be used for lighting purposes; this technique is known as image based lighting (IBL) and can produce extremely realistic lighting effects in rendered images.