Monday, December 31, 2012

Happy New Year

From all of us, to all of you ... a happy and prosperous new year. Thank you for your continued support.

Wednesday, December 19, 2012

AmpedFive adds Color Deconvolution

Remember this article? Color deconvolution is an awesome tool for complex background removal that has applications across a number of forensic disciplines. Now, it's part of Amped FIVE. How cool is that?!

If you haven't checked out Amped FIVE, you owe it to yourself to spend a few moments to see just how robust this tool is. Latent Prints, Questioned Documents, Footwear, Tool Marks, Photogrammetry in 2d or 3d, Video, Images ... you name it. All for a very reasonable price. Well worth the investment.

Friday, December 14, 2012

The Perils of Using the Local Computer Shop for Computer Forensics

Along the lines of when is an expert not an expert, Larry Daniel posts the following quote in his article about using an unqualified person to perform computer forensics,

"Hickory Brands hired a service provider called Computer Ants, whose owner and operator, Thomas Scott, testified to never having performed forensic services in the context of a lawsuit. Scott, who the defendants tasked with producing documents responsive to search terms from a total of 308 million potentially relevant files on 35 computers and six servers, had previously worked as a truck driver and a security manager for Bass Pro Shop."

"The result was the delivery of 1,700 sensitive documents to the opposing counsel that resulted in a heated clawback motion, in which the judge found that the attorneys did not take the "reasonable steps" required by law to prevent the disclosure."

You can read more about that case by clicking here.

Tuesday, December 11, 2012

New Exclusive Photoshop Features for Creative Cloud Members

For a closer look at what’s new in Photoshop CS6 (13.1), click here.

Some of the improvements that may interest you are:

Retina Display Support
See more of the details in your images and in the Photoshop user interface when viewing on new Retina displays available on MacBook Pro.

Workflow improvements
Discover new user-inspired timesavers including Crop tool refinements, better naming of merged layers, the ability to quickly move a path anchor point using the spacebar and the option to see up to 100 items in your list of recently opened files. Easily create large images for signage, panoramas, and other large outputs by saving JPEGs of up to 65,000×65,000 pixels, more than twice the size previously supported. Ensure consistent type formatting across multiple documents by defining global styles, which are then available in any Photoshop document.

Conditional Actions
Speed up image processing by creating Conditional Actions. These commands use logic to automatically choose between different Actions based on rules that you establish.

Note: With the exception of Retina display support, the new features listed above will only be available to Adobe Creative Cloud members. For government and non-CC members, it just got interesting.

Monday, December 10, 2012

The costs of government

I try to keep up with current events. I read an article on about government employee costs under the title, "$822,000 Worker Shows California Leads U.S. Pay Giveaway." Being a part time government employee, I'd like to offer a bit of a rebuttal.

Point 1: "Today, the state’s highest-paid employees make far more than comparable workers elsewhere in almost all job and wage categories, from public safety to health care, base pay to overtime." - This interesting page makes the point that police detectives make more than private detectives on average and by region. What's lost on both pages is the fact that private sector workers can work as much as they are able, take on additional work, work for whomever they like, and negotiate for all of those conditions individually. Speaking of my own situation, I don't set my wage or working hours (no matter how hard I work, or how much I innovate, I get the same rate as everyone else in my pay grade). I don't have a say in benefits (including retirement). I can't actually opt out of my benefits package. I have to pay the union for the privilege of bargaining against my interests. I can't have a second job unless the city gives me permission. I don't get money for overtime worked - I get time off (which has to be used before vacation time). I don't get to go home until I'm relieved, which can be days beyond when I'd like to go home. Thus, there really is no comparison to a police detective and a private detective. The only real thing that we have in common is that we can both quit, and walk away (though my costs would be substantially higher).

Point 2: "From coast to coast, states are cutting funding for schools, public safety and the poor as they struggle with fallout left by politicians who made pay-and-pension promises that taxpayers couldn’t afford." - In California, the state is controlled by a supermajority of Democrats. Democrats and organized labor have walked hand-in-hand for generations. It's borderline conflict of interest to have the two negotiating over wages and benefits. Yet, there's more to the story. California is a magnet for those seeking opportunity. There's one side, those wishing to start a business and grow wealthy. Then there are those who come from all over seeking to avail themselves of our rather generous social programs. California, with 12% of the U.S. population, has one-third of the nation's welfare recipients. This influx of people requiring state services comes at a cost. Which would you rather pay for, schools, police, libraries, parks? All of the above? As each constituency fights for its piece of the pie, there will be winners and losers. Right now, the losers are the tax payers - who after Jan 1 will be some of the most burdened in the country.

Point 3: "“All it took was for political leaders to think more about the general population and the future, rather than their political futures,” said Crane, a Democrat who worked as an economic adviser to former Governor Arnold Schwarzenegger, a Republican. “Citizens should be mad as hell, and they shouldn’t take it anymore.” - Citizens aren't mad as hell. They voted in a Democrat supermajority - see point 2. The results of my own state assembly district is still up in the air. As it stands, the democrat challenger is ahead by 145 votes. With one party rule - they can do whatever they like (for good or ill). We'll see where the democrats lead the state.

Point 4: "Last year, Brown waived a cap on accrued leave for prison guards while granting them additional paid days off. California’s liability for the unused leave of its state workers has more than doubled in eight years, to $3.9 billion in 2011, from $1.4 billion in 2003, according to the state’s annual financial reports." - Why did the governor need to uncap accrued leave? How many prison inmates are in California's prisons? Is the trend rising or falling? Why? Inmates need to be housed and guarded 24 hours per day. They need food, laundry, medical care, and etc. Has the corrections realignment helped or hurt the overall situation? Is passing the buck to the counties a solution, or does it just postpone the problem?

Point 5: Elections have consequences. Here's the 2012 Platform of the political party that controls California. Every item has an actual cost today, plus a compounded (future) cost. Our education system "was once the envy of America. Our K-12 schools were among the best funded in the country and under the leadership of Governor Pat Brown, the California Master Plan for Higher Education made our community colleges, our California State Universities and our University of California institutional systems to emulate throughout the world. In recent years, our continual disinvestment from education threatens our ability to offer our youth the education they require to usher our state into the future." This statement from our leaders flies in the face of our state's constitution - which requires that a minimum of 40% of the state's general fund be spent on education. The actual number is closer to 50%. Thus, 50% of the world's 7th largest economy is spent on education ... and our kids are suffering? Where's the money going?

Here is the platform of a party that holds no current influence in Sacramento. Again, each of the items contained in the Libertarian Party's platform has a cost, as well as a savings for those areas that they think government should no longer control. Items 1 and 7 would reduce the prison population by about 40%. Item 10 is a huge cost saver - but now out of line with Obamacare. Item 18 gets rid of the state's ABC system. And so on ...

Thus, elections have consequences. California's voters chose to have a supermajority of leaders who believe in a large, all encompassing government. That choice has a high cost. If the voters really were mad, then the 2014 elections should see the Libertarian Party sweep into office ... and a massive redistribution of responsibilities back to the individual.

John Overton was right.

Thus endeth the rant.

Tuesday, December 4, 2012

Single View Metrology

Criminisi, et all, in their work Single View Metrology, describe how 3D affine measurements may be computed from a single perspective view of a scene given only minimal geometric information determined from the image. This minimal information is typically the vanishing line of a reference plane, and a vanishing point for a direction not parallel to the plane. Their work shows that affine scene structure may then be determined from the image, without knowledge of the camera’s internal calibration (e.g. focal length), nor of the explicit relation between camera and world (pose).

In particular, they show how to (i) compute the distance between planes parallel to the reference plane (up to a common scale factor); (ii) compute area and length ratios on any plane parallel to the reference plane; (iii) determine the camera’s (viewer’s) location. Simple geometric derivations are given for these results. They also develop an algebraic representation which unifies the three types of measurement and, amongst other advantages, permits a first order error propagation analysis to be performed, associating an uncertainty with each measurement.

They demonstrate the technique for a variety of applications, including height measurements in forensic images and 3D graphical modelling from single images.

Building on this foundation, the Measure 3d tool in Amped FIVE computes real-world distances directly on the image. The Measure 3d Single View Metrology implementation is based on the fact that some image lines, which are parallel in the real-world, join in a point in the image, named the vanishing point, due to the perspective. The vanishing points themselves are obtained by identifying, thanks to the geometric information (two or more lines for each x/y/z direction) provided by the user, sets of 3D points (x,y,z) that belong to the segment lines for each direction of interest. The scene perspective can be reconstructed from vanishing points: transforming the geometric information into a system of linear constraints on the coordinates of the 3D points and using the 2D observations (the known distance) to further constrain the 3D points. As result, 3D measurements may be computed from a single perspective view of a scene given only this minimal geometric information determined from the image.

The validity of the Single View Metrology approach is assessed by the Monte Carlo statistical tests: it determines how the uncertainty propagates from input to output of the computation chain and estimate the measurement accuracy.

But, as powerful as Amped FIVE is, it's only as good as the inputs received from a trained analyst. One of the examples used in my training sessions is a video from a convenience store. I have been to the scene and measured the floor tiles as 12" square. There is a discernible checker board pattern to the tiles, so it's easy to get X and Y segments from an 8' x 8' block of tiles. The store has two entrance/exit doors with security measuring tape affixed to the door frames, giving us the Z. Once this information is put into FIVE, measurements can be taken from within the scene with a high degree of reliability.

The biggest difference between SVM based photogrammetry, and methods like reverse projection photogrammetry, or products like iWitness, is that isn't the need to re-shoot the scene. Measurements are taken of the area that was captured by the video already in hand, like the floor tiles and the door frame - things that don't generally change. These measurements are then used for your calculations, lowering costs and time to completion / results.

Thus, if your are interested in adding Photogrammetry to your offerings, you should consider adding Amped FIVE to your tool kit.

Monday, December 3, 2012

Measuring within images

Here's a question - is it possible to measure within images? The answer, of course, is yes (with a gigantic caveat). It depends on what you mean by measure, and what it is that you'd like to measure.

In Amped Five, you have the ability to measure in 1d, 2d, and 3d. Tomorrow, we'll look at 3d measurements. Here's a look at 2 dimensional (X,Y) measurements within images.

The Amped FIVE Measure 2d tool computes a specific measurement distance in a rectified image. Image rectification corrects image distortion by transforming the image into a standard coordinate system (think perspective correction). Given an image of a planar surface (2d), points on the image plane can be mapped into corresponding points in the rectified plane by means of a projective transformation called homography. Points in one plane are mapped into the corresponding points in the other plane as follows:
X = Hx where x is an image point, X is the corresponding point on the world plane and H is the 3x3 matrix representing the homography transformation. Once the homography matrix H is known (or has been computed), any image point can be mapped into the corresponding location on the rectified planar surface and distances between actual points can be extracted by computing the Euclidean distance d(X1,X2), where X1 and X2 are the actual points of the two points x1 and x2 on the image plane. The homography is computed directly from a set of at least four points by the Perspective Correction filter.

Correct Perspective, in FIVE, maps a desired quadrangular region to a rectangular one, which allows seeing the plane of interest as the plane of the image was parallel to it. Pixel values are interpolated with a bicubic algorithm. (Anil. K. Jain, Fundamentals of Digital Image Processing, Prentice Hall, pp. 320-322, 1989.)

So what's the takeaway here? Measuring planar surfaces, or making two dimensional measurements within images, requires that a perspective correction process be applied first. If this isn't possible, then you should consider 3d measurements - which will be covered tomorrow - that deal with perspective as it is, and factors/computes the vanishing point in the image.