acknowledgements for ansi/nist-itl 1-2011 - NIST Visual Image ...

ANSI/NIST-ITL 1-2011 - UPDATE 2013 DRAFT VERSIONof 1 or 2, the transmitted horizontal and vertical scales shall be the same. A value of 1 or 2shall also be specified for latent friction ridge prints if the lifted latent print is transmitteddirectly from a scanner. If the latent print is contained in a photograph, a value of 1 or 2shall be entered only if the image of the latent was captured with a scale measurementvisible in the image and the pixels across an inch or centimeter can be calculated – given theknown characteristics of the camera and its distance from the latent print. A value of 0 for alatent print indicates that the true ppi value of the image is not known.For non-contact images of body parts, SLC shall be set to 0 unless the object being imagedis a fixed distance from the capture device and the ppi or ppmm values for the capturedevice are accurately known at that fixed distance. (An example might be an iris capturedevice with a very small effective capture zone).These are the SLC fields.Field 9.130: M1 scale units / SLCField 10.008: Scale units / SLCField 13.008: Scale units / SLCField 14.008: Scale units / SLCField 15.008: Scale units / SLCField 16.008: Scale units / SLCField 17.008: Scale units / SLCField 19.008: Scale units / SLCField 20.008: Scale units / SLC7.7.8.4 Transmitted horizontal pixel scale / THPSThis is the integer pixel density used in the horizontal direction of the image if SLC has avalue of “1” or “2”. If SLC has a value of “0”, this [2013e>] field [] When using certain formats, such as PNG, conversion from ppm (or or otherscales) may result in a decimal value. Since these fields require integer values, roundingup should be used. For example with the values 1.3, 1.5 and 1.8 the resulting THPSvalues would be 1, 2, and 2. [