Digital Still Image and Photo Enhancement
There is much more to a digital image or photograph than what you see.
An image captured by a digital camera (still image or a frame of a motion video) is an interpretation and at most, a best effort presentation of light (photons) entering the lens and striking the image sensor. It is never an exact replication of what the eye sees due to the nature of digitisation and physical manufacturing constraints. Digitising an image involves sampling, quantisation, interpolation, filtering and the application of various mathematical algorithms to counter or enhance various characteristics of the camera lens, lighting quality, motion of subject or camera, sensor size and response values etc. For example, a common sensor structure has 50% of the sensor’s pixels filtered to register only Green wavelengths, with 25% each for Red and Blue wavelengths in an interleaved pattern known as the Bayer Mosaic Pattern. To fill in the missing colours, values are interpolated by averaging surrounding values for that missing colour.
The forensic enhancement of an image provides a means of adjusting some of these in-camera settings and characteristics to overcome what may be limitations of the cameras ability to interpret the incoming light or incorrect settings used by the operator of the camera. This is done with the objective of not adding to the image anything that was not already there, or removing anything without clearly specifying what was removed and why.
All images can be enhanced to some degree. However, there are many factors that will impact on the effectiveness and degree of enhancement. There are two critical areas that do have a big impact on the outcome are as they cannot be undone i.e you cannot un-bake the cake. The first issue is the number of pixels associated with the subject of interest which are controlled by the resolution of the image, distance of the subject of interest from the camera and the focal length of the lens (field of view). The other key issue is the amount of compression applied to the image, which impacts of the amount of detail that is thrown away in an effort to keep down the file size of the image. Both of these critical issues are usually under the control of the operator of the image taking device (camera). However, the impact of choices regarding settings that affect these issues are often not realised or over-ridden by a desire to fit more images onto a given storage media etc. For example, if there are only 6 pixels representing a persons head or number-plate, you will never get enough enhancement to recognise or identify the subject. Alternatively, if you have more pixels associated with the subject but set the compression to high, which throws away all the fine detail, then you will just be left with nice big square blocks (8 x 8 pixels or greater) of colour which cannot be recovered from and will be useless for identifying anything.
Photo Formats and Media Handling.
Film Positives and Negatives.
Positive and negative film images are cleaned and then scanned at up to 9600 x 9600dpi optical resolution with 48 bit (16-bit per colour) sampling in a multiple pass configuration and Infrared mode. This provides the best possible starting point for analysis and enhancement of the images. We currently support 35mm or 120 format film and mounted or unmounted slides.
Photo Print Scanning and Re-processing
If the original negatives are not available, photo prints can be re-scanned at up to 4800 x 4800dpi optical resolution with 48 bit (16-bit per colour) sampling in a multiple pass configuration and Infrared mode. This provides the best possible starting point for analysis and enhancement of the scanned images. We currently support up to A4 / Letter size images.
RAW formats are the ideal source to work with. However, any digital format can be re-processed and improved upon to suit your needs. Please avoid resaving or renaming the image if at all possible, the closer to original the image is, the better the enhancement process can be. If your image is still on the camera (or video), output the image in as high a resolution and as low a compression setting as possible to ensure the highest possible quality. Use the following formats to output your photo or image in the following order of preference – RAW then TIFF and lastly JPG (JPEG).
If the image is derived from a video clip, best results will be obtained by providing the video clip itself, and we will use the best possible means of exporting the image as required to minimise loss of quality. This may include the combining of a number of images to produce an enhanced single image.