One of the most commonly litigated issues regarding digital image evidence is the propriety of and limits to image clarification. Parties who tender clarified images argue that the clarified images allow the viewer to see more detail in the images while the opposing party urges the court to rule the images inadmissible on the basis that the images have been rendered inaccurate, misleading or confusing. There is a growing body of case law on this issue which is instructive for both those who clarify images and the attorneys who tender them in court.

Courts have ruled on many aspects of image clarification or enhancement, including the following:

• Images subjected to computer enhancement or clarification
• Image sharpening
• Softening pixels to remove graininess
• Adjusting contrast and brightness
• Enlarging images

Some case comments are noteworthy as they show how courts view the clarification or enhancement of images. While some of the older cases refer to analog images, the same principles will apply to digital images.

United States Cases

In Nooner v. State of Arkansas, 907 S.W.2d 677 (1995, Supreme Court of Arkansas), regarding the clarification and enhancement of analog video evidence, the Court stated at p. 686:

Reliability must be the watchword in determining the admissibility of enhanced videotape and photographs, whether by computer or otherwise.

The Court ruled that computer generated images are admissible if they are verified as being reliable representations of images recorded on the original videotape. Further, the original videotape should be entered as an exhibit for the trier of fact to view. As each of these requirements was met in this case, the defendant’s argument failed.

In United States v. Beeler, 62 F. Supp.2d 136 (1999, United States District Court, D. Maine), an ATF audiovisual enhancement expert enhanced the quality of the images by adjusting the contrast and brightness of those images and enlarging portions of the images that depicted the subject. He did not modify the original images – rather, he made them easier to see. The ATF expert testified that he recorded each step he undertook in this process.

The defendant argued that the enhanced images were inadmissible pursuant to the best evidence rule and that they were untrustworthy because they are susceptible to tampering and subsequent modification through enhancement.

As noted earlier in an earlier post on authentication, the tendering party must establish that the enhanced images are accurate, authentic and trustworthy. The Court was satisfied on each point in this case, ruling at p. 149-150 that:

The enhanced version is different only in that extraneous frames are no longer present and the images are larger, clearer and easier to view…The edited and enhanced versions of the Mobil Mini-Mart surveillance videotape are admissible because they have been proven accurate and serve to present the substance of the original videotape in a more easily understood form which is in accord with the spirit of the best evidence rule.

Similarly, in Dolan v. State of Florida, 743 So.2d 544 (1999, Court of Appeal of Florida, Fourth District), the Court stated at p. 546 that:

Once the tape is authenticated and the forensic analyst explains the computer enhancement process and establishes that the images were not altered or edited, then the computer enhancements become admissible as a fair and accurate replicate of what is on the tape, provided the original tape is in evidence for comparison.

United States v. Seifert, 351 F. Supp. 2d 926 (2005, United States District Court, Minnesota), is an instructive case on image clarification. Three specific processes applied by the analyst were challenged, namely:

• Circling images of interest for the purpose of identifying the suspect.
• Enlarging the circled images.
• Adjusting the brightness and contrast of the circled images.

The defendant argued that these processes made the video evidence untrustworthy and therefore inadmissible as the digitized and enhanced copies were no longer an accurate duplication of the original analog images. In analyzing this issue, the Court said at p. 928:

Defendant claims the enhanced video no longer accurately records the surveillance images, and, as such, is no longer an admissible original recording. The Court does not agree, and finds the proffered tape may be admitted.

The government has carried its burden and laid adequate foundation showing the enhanced tape “accurately reproduce[s] the scenes that took place, [and is] …accurate, authentic and trustworthy.” United States v. Beeler, 62 F. Supp. 2d 136, 148-49 (D. Maine 1999). During the evidentiary hearing, the Court viewed the “before” and “after” images. The Court finds the enhanced version to be a fair and accurate depiction of the original videotaped image. The enhancements more readily reveal, but remain true to, the recorded events. As such, they may be entered into evidence before the jury.

The first image transfer — from analog to digital format — changes the image only in a metaphysical sense. The viewer’s perceived image is identical. This transition has no effect on the accuracy of the image. In the Court’s view, it is an “equivalent [duplication] technique which accurately reproduces the original.” Fed. R. Evid. 1001 (4).

Beyond this, the Court finds that adjustments to brightness or contrast, or enlargement of the image, while arguably a manipulation, are in fact no more manipulative than the recording process itself. The image is black and white; the world is not. In the non-digital world, a camera’s lens, its aperture, shutter speed, length of exposure, film grain, and development process — all affect the image. Each of these is entirely unremarkable so long as the “image” remains an accurate recording of that which occurred before the camera. If a photographic negative were magnified by lens, and an enlarged image resulted, no one would question the larger picture. Similarly, in the event of a tape recording, no one would comment if the volume were increased to make a recorded conversation more easily heard — again, so long as the volume-increased words were accurately recorded by the recording medium.

Here, the evidence showed that the technician adjusted the digital image’s brightness and contrast, but maintained the relationships between the light and dark areas of the image. As an example, if the moving figure’s clothing were a certain percentage lighter or darker than the wall behind it, that light/ dark relationship was maintained. The technician testified that he simply “moved” the brightness relationship on the scale, increasing the light’s intensity while maintaining the image’s integrity.

As a result, the Court finds that the enhanced tape accurately presents a true and accurate replica of the image recorded by the Co-Operative’s security camera. It does so in a fashion which maintains the image while assisting the jury in perceiving and understanding the recorded event. Compare Beeler, 62. F. Supp. 2d at 149 (admitting videotapes where enhancements omitted “extraneous frames” and “the images are larger, clearer and easier to view”); United States v. Luma, 240 F. Supp. 2d 358, 368 (D. V.I. 2002) (admitting videotapes where enhancements “did not change the substance of the videotape, but merely clarified the tapes.”)

Accordingly, the Court finds the enhanced videotape is a duplicate admissible under the best evidence rule. Fed. R. Evid. 1001 (4), 1002, and 1003.

Accordingly, the defendant’s motion to exclude the enhanced video images was denied and the prosecution was permitted to use the clarified and enhanced images at trial.

This ruling was appealed to the United States Court of Appeals for the Eight Circuit (445 F.3d 1043 (2006, United States Court of Appeals, Eighth Circuit)). The defendant argued that the District Court erred in admitting the enhanced video because no one could be certain whether it accurately reflected the original video given that the state’s forensic video analyst did not record the changes he made to the original video and therefore, no audit trail. On this point the Court of Appeals ruled that since the analyst described in detail each step taken in the enhancement process, that was sufficient to establish authentication, even though he did not keep copies of the images at each stage of the enhancement. The Court of Appeals was further satisfied that adjustments to contrast and brightness were applied to the images as a whole and not just selected portions. Accordingly, it ruled that the District Court was correct in allowing the admission of the clarified and enhanced video evidence at trial.

Even in 2015, courts are still facing challenges to the admissibility of surveillance video on the basis that image clarification is an unproven scientific process. In State of California v. Cole, 2015 WL 5838774 (Court of Appeal, Second District, California), a shooting was captured on VHS tape by a surveillance system. The time lapse system recorded still images from five different cameras resulting in video images that were overlaid and of no use. A forensic video analyst digitized the VHS video and isolated the parking lot camera images as they were the only relevant images. The images were then enlarged and color and contrast adjustments were made to improve image quality. The images were still of poor quality, such that the individuals observed were not identifiable. There was no date and time stop on the images either. Yet the video did show the shooter’s arrival, the shooting and the arrival of paramedics a short time later. At trial defense counsel objected to the video evidence on the basis that it was not in real time, was not complete and lacked a date and time stamp. The trial court overruled the objection explaining that such issues could be argued to the jury. The Court of Appeal upheld the trial court and also dismissed an argument brought on appeal but not at trial. The defense argued on appeal that the video evidence should have been subjected to a People v. Kelly analysis as new forensic processes were utilized in this case. Aside from the fact that this issue could not be argued on appeal for the first time, the record showed that nothing the forensic video analyst did utilized a new scientific technique as “the practice is a common one taught in high school visual arts classes.”

Canadian Cases

In a similar vein, in R. v. Cooper, [2000] B.C.J. 446 (British Columbia Supreme Court), the Court addressed the impact of image clarification on admissibility at p. 11:

In my opinion the digitization, blowing up, and lightening of the images on the videotape does no more than enhance or clarify the images. They are not changed. The digitized images are the same images seen on the videotape. One need only compare the faces to see that the images have not been changed in the manner contemplated by Nikolovski.

In another Canadian case, R. v. Pasqua, 2008 ABQB 124, 2008 CarswellAlta 221 (Alberta Court of Queen’s Bench); appeal allowed 2009 CarswellAlta 974, 2009 ABCA 247 (Alberta Court of Appeal) for reasons not relating to video evidence, the trial judge commented as follows on image clarification at p. 3:

As noted earlier, the raw video is very grainy, has low-quality still images, and colour variations are extremely subtle. The actions of the persons displayed are extremely difficult to track with the untrained eye. The proposed evidence describes technological processes used to enhance the video and to track the images therein, and provides knowledge not readily accessible to, and insight outside the experience of, the triers of fact. The digitization and enhancement is a useful tool in enhancing and clarifying the video, to assist the court in viewing and assessing the original images… The images in the enhanced video have not been changed. They are the same images as seen in the original video, only enhanced and with attention drawn to aspects of them. The enhanced video does not add or detract from the content of the original. The original video evidence remains substantially unaltered and the enhancements (each in separate digital files) serve merely as a visual aid to assist the triers of fact.

A Final Word

What is consistent in the foregoing cases and many others is that images that have been clarified or enhanced should be ruled admissible provided the person who performed the clarification or enhancement processes testifies to the following key elements:

• The computer processes that were employed.
• That the images are fair and accurate versions of the original images despite the clarification or enhancements.
• That the images are reliable.
• That the clarification or enhancement allows the trier of fact to garner more detail and information from the images.
• That the original images are available for review.

Provided the foregoing testimony is given and all processes are fully and competently explained there should be no bar to admissibility of the digital admission evidence. Beyond that, it will be up to the trier of fact to determine how much weight to give to the evidence.