Image Enhancement Technology
by Bill Siuru, Ph.D., PE
Surveillance and cell phone cameras are everywhere today. All too often, however, video images of suspects are unclear and require the use of specialized enhancement tools.
A surveillance camera captured an altercation between 30 teens on a basketball court when one was shot. From camera images, Detective John Mullholland, an evidence technician with the Hamilton County (Ohio) Sheriff's Office Criminal Investigation Section, produced snapshots of the teenagers, determined where each was standing, and what they were wearing. Comparing witness statements to the snapshots, investigators identified the shooter who was convicted of the crime. This is just one of the many successes of Salient Stills' VideoFOCUS forensics products widely used by law enforcement agencies.
Cameras Are Everywhere
A huge number of crimes are now recorded with the proliferation of video cameras and CCTV video. This includes surveillance, stakeout cameras, and intersection cameras - plus those in police interview rooms. This adds up to a massive amount of imagery to be processed, analyzed, and condensed in presentable form.
Often, images are noisy, poorly exposed, multiplexed, low-resolution, and taken with a shaky camera or from a moving vehicle. Another challenge is the different, often proprietary, file formats which are not easily transferable for processing and analysis. For evidence used in court, the end product must not only be easy to understand and convincing, but video integrity and preserving the chain of evidence are also a must.
Salient Stills' latest products, VFPro 3.0 and VFSource v2, are designed to meet these requirements while making it easier to capture and import video and produce usable stills and video in minutes. Working with law enforcement, VideoFOCUS products were created from the ground up for users including first responders and CIS professionals. VFPro 3.0 is for video forensics analysts and contains all of the features needed in the CIS environment. VFSource v2 is for use in the field for quick video retrieval and review. You can capture a source video: easily pull stills; do simple processing; and save or export images.
A Caveman Can Use It
Both are easy to use. According to the company, the learning curve is two hours, not two weeks. This is especially attractive for small agencies in which people don't use the system daily and where there are frequent reassignments.
VFPro requires only a computer running Windows XP. No proprietary hardware is needed since all of the tools required are included. There is no need to piece together various tools, such as a separate digitizing tool or a screen capture tool for proprietary video. You don't have to stop to launch image and movie enhancement tools like Photoshop or Premiere. It can capture DV direct from an OHCI compliant FireWire port or from a DirectShow compliant capture card. You can import most common media file formats or use its screen capture function to grab video from proprietary digital video player applications.
Users can import and easily work with a wide range of file types, including formats .avi, .mov, .wmf, and .asf, as well as streaming video and cell phone movies. Likewise, VFPro 3.0 exports digital movie files to industry standard formats and compression types, including .mov and .avi with movie data stored in a wide variety of codec types, including uncompressed, DV, MPG, MJPEG, and many others. Still image types accommodated include .jpg, .bmp, and .tiff. Original unenhanced raw video images can also be exported and images can be printed directly or exported.
As an example of its capability, when "Create Still" is selected, seven frames of a video, three preceding and three succeeding the frame of interest are displayed with the relative strength each image will play in averaging to get the final still. A huge picture is presented to enhance reviewing of details.
A Host of Features
Investigators can inspect and zoom into smaller areas of videos and stills, with new filters available for both still images and video. Filters in VFPro 3.0 can, for example, sharpen, equalize, blur, adjust levels, and convert color. Shaky video can be stabilized for better and easier analysis and presentation. All filter dialogs have side-by-side input and output viewers with basic transport controls, so you can gauge the filters.
The new VFPro 3.0 version includes new image processing filters for quality output. An advanced editing tool means that you can now trim, crop, cut, paste, and combine video clips and even add still images to movies. Results are viewable instantly, unlike many time line-based editing systems which require a rendering process with longer delays as the length of the video to be processed increases.
Important for court proceedings, VFPro 3.0 produces results without destroying the source material and creates a detailed audit of media processing. Records are made and stored with each session and still made. A hierarchical audit file can be viewed with a simple text editor. No data is ever overwritten. Whenever a process is run on a video or still, another copy is made, and it's easy to select all related video derived from an original.
With VFSource v2, law enforcement officers can quickly capture images of suspects, persons of interest or pieces of evidence in the field. Within minutes, stills and video are ready to be shared. The v2 upgrade features advanced screen capture and import utilities, audio capability, an intuitive user interface, and more powerful video and image processing. This includes the ability to more easily extract still images from video files for export and printing; drag and zoom to better inspect both still images and movies; adjust still image properties; and crop, size and change aspect ratio.
VFSource and VFPro have most of the same analog and digital image and capture capabilities, as well as the ability to export video and still images in a variety of formats. VFSource does not have the image and super resolution filters for still images or the more robust video editing. Likewise, video filters, video stabilization, and object tracking are omitted, as is the comprehensive audit trail capability. Also, there is only manual de-multiplexing, but not the automated version.
About the Author: