Michael T. Stevens

 

Software Architect/Color and Image Scientist

 

Michael.Thomas.Stevens@gmail.com

 

(503) 642-3430

 

Career Objectives

To seek and implement creative solutions for difficult engineering challenges in the areas of color correction and image processing. Create superior products through superior engineering techniques.

 

Summary

 

Programming - World class C programmer specializing in optimized embedded code: memory footprint, size, and speed. Expert PostScript programmer: driver optimization, embedded code and feature creation. Proficient in numerous other languages including, but not limited to, JAVA, C++, makefiles, assembly, shell scripts, and HTML.

 

Mathematics - Continually exploring a variety of mathematical disciplines: multi-variable calculus, linear algebra, number theory, topology, discrete mathematics, cryptography, spatial/temporal transforms, curve fitting problems, probability analysis, information theory, and differential equations.

 

Color And Imaging - Years of experience with all aspects of imaging hardcopy: rendering, color matching, halftoning, artifact removal, and subjective adjustments. Inventing new algorithms for both software and hardware.

 

Technical Leadership - Driving technology through conception, design, implementation, documentation, and post launch support pipeline. Implementing creative solutions that are both backward and forward compatible. Mentoring junior members of the team. Delivering more than expected.

 

Expertise - Multifaceted, highly technically competent (the "go-to guy" for difficult problems), versatile, adaptable, and able to quickly become an expert in niche disciplines.

 

Special Recognition - 2009 CRN Xchange Tech Innovator of the Year award

 

 

Experience

 

Software Architect at HCL / Xerox / Tektronix

September 1997 - Present (14+ years)

 

Types Of Software - image rendering, memory management, garbage collection, color management, print driver features, password encryption, data compression, computer modeling, search algorithms, advanced data structures, hashing schemes, graphical user interface (GUI), 3D modeling (OpenGL), and tool development.

 

Computer Languages - C/C++, PostScript, makefiles, shell scripts, HTML and assembly.

 

Operating Systems - Solaris Unix, Linux, Windows, embedded Linux, VxWorks, and other proprietary embedded operating systems.

 

Revision Control Software - Clearcase, Clearcase UCM, Accurev, and CVS.

 

Environment - Agile software development, acting as both technical lead and subject matter expert, member of the Xerox Technical Advisory Panel.

 

Projects: Architect of PostScript color feature code (multi-site code development on four continents); developer of Color By Word technology, password encryption, PhaserMatch color matching application, global print driver color features (from the UI down to the rendering), user print calibration, secure print, run-time configurable color architecture, irrational screening, color interpolators, color halftoning for both laser and solid ink products, ICC profile generation for all office products, CRD design, frame buffer compression, fast rendering architectures, halftone algorithm for solid ink medical devices, visual compensation between film and paper, new color tools, digital copier image pipeline, new out-of-gamut mappings, and improvements to printer imaging pipeline.  Technical lead for image quality of medical imaging product line.

 

Member Of Technical Staff III at QMS, Inc

September 1994 - September 1997 (3 years 1 month)

 

Types Of Software - image rendering, color management, print driver features, data compression, computer modeling, search algorithms, hashing schemes, advanced data structures, and imaging tools.

 

Projects: Conceived and developed color profiling tools, changed Postscript printer code to accept proprietary technology for dithering and color rendering, developed a fast color matching pipeline for scanners, evaluated and generated new stochastic screens, implemented frame buffer encoding scheme into Postscript printer code, and did extensive work in both lossy and lossless data compression.

 

Physicist at CalComp

April 1993 - September 1994 (1 year 6 months)

 

Types Of Software - computer modeling, data compression, 3D modeling, graphical user interface and image rendering.

 

Projects: Quantified image quality, created tools for halftone linearization, developed a new ordered dither through the use of super cells, and developed color profile generation tools. Created artifact reduction algorithms for dye sublimation, thermal transfer, and laser printing technologies, and stochastic screen generation algorithms.

 

Software Engineer at DP-Tek

June 1991 - April 1993 (1 year 11 months)

 

Types Of Software - graphical user interface (GUI), device drivers, data compression, and computer modeling.

 

Projects: Computer modeling of the laser and semiconductor material interaction within laser printers, developed data compression algorithms, calibrated resolution enhancement technologies on laser printers, implemented edge detection technologies, created new halftoning algorithms, prototyped new implementation of laser gray scale technology, wrote code for image processing, developed software from the application level down to the driver level, IC debugging on high speed circuit boards, and generated test vectors for ASIC simulation.

 

 

Patents

 

Color printing

United States Patent 8149454 Issued April 3, 2012

Inventors: Michael Stevens, Meng Yao, Paul W. Philippi, Michael D. Stevens

A method of operating a color printer including using a first set of one-dimensional TRCs or a second set of one-dimensional TRCs with a single set of color tables.

 

Color control of PDL CIE color

United States Patent 8121402 Issued February 21, 2012

Inventors: Michael Stevens

A method for processing image data includes receiving image data including an assigned color space, comparing the assigned color space of the image data to a known color space, and processing the image data using the known color space in place of the assigned color space if the difference between the known color space and the defined color space is below an acceptable threshold. The method is particularly suited for use with Adobe PostScript applications.

 

Systems and methods for image data encoding and decoding

United States Patent 7936917 Issued May 3, 2011

Inventors: Michael Stevens

Image processing systems and methods are presented for encoding 8-bit color image data to 4-bit data using an encoding table by assigning a pixel type value to each 8-bit pixel according to a 9x3 tiling pattern with 9 unique pixel type values in each 3x3 window of the 9x3 tiling pattern, and for decoding the 4-bit image data based on the pixel type value and the encoded data values for neighboring pixels

 

Database system for processing image data for consistent color printing

United States Patent 7920292 Issued April 5, 2011

Inventors: Michael Stevens

Present systems and methods enable digital color printers to consistently print color output from computer generated image data that includes spot color definitions. Colors that are defined as spot colors can be separated from colors that are defined as combinations of process colors. Accordingly, color corrections can be separately applied to objects that are defined by spot color definitions to provide customized image processing that provides printed color images with improved quality

 

Method and system for improved space filling interpolation

United States Patent 7864366 Issued January 4, 2011

Inventors: Michael Stevens

Document processing systems and methods are presented for transforming color image data from an input color space to output color space using space filling interpolation to mitigate loss of color information at the corners of color gamuts. An initial interpolation of the input color space pixel values for each pixel is performed to compute initial output color space pixel values, and these are converted into luminance-chrominance color space pixel values. A adjustment value # is then computed according to the luminance-chrominance color space pixel values, and final output color space pixel values are computed according to the initial output color space pixel values and the adjustment value #.

 

Abstract parameter print mode mimic generation

United States Patent 7729007 Issued June 1, 2010

Inventors: Michael Stevens

A method, system, and computer program for generating a visual representation provides the capability to illustrate the various combinations of settings quickly and efficiently. A method for generating a visual representation comprises providing a plurality of predefined visual representations, accepting a plurality of values of a plurality of parameters, and generating a visual representation representing effects of the parameters based on the predefined visual representations and on the values of the parameters.

 

Range normalization for entropy reduction arithmetic encoding/decoding

United States Patent 7652599 Issued January 26, 2010

Inventors: Michael Stevens

What is disclosed is a novel system and method for performing renormalization in a data entropy reduction process of an image in a compression path. An accumulator is used for one of arithmetic encoding and decoding according to an arithmetic coding process and a number of most significant bits of the accumulator represents an output segment. If processing an input data symbol is determined to be able to cause a change in a value of the output segment, the encoding range is changed. If the size of the encoding range portion that can cause the output segment value to change is less than the size of the portion of the encoding range that fails to cause the change, the encoding range is limited to the size that can cause the change. Otherwise, the encoding range is set to the size that fails to cause the change.

 

Processing image data for consistent color printing

United States Patent 7616346 Issued November 10, 2009

Inventors: Michael Stevens

Present systems and methods enable digital color printers to consistently print color output from computer generated image data that includes spot color definitions. Colors that are defined as spot colors can be separated from colors that are defined as combinations of process colors. Accordingly, color corrections can be separately applied to objects that are defined by spot color definitions to provide customized image processing that provides printed color images with improved quality

 

Dynamic color rendering dictionaries

United States Patent 7310165 Issued December 18, 2007

Inventors: Michael Stevens

Dynamic Color Render Dictionaries are provided to automatically switch color rendering behavior between object types. The implementation resides entirely within the Color Render Dictionary (CRD) and requires no changes to the state of the Postscript interpreter (There are no required "C" code changes and Postscript operator redefinitions.) The different color rendering behaviors are accomplished by concatenating multiple color transform tables into a single/RenderTable within the CRD. The different rendering behaviors are accessible to single graphics state by simply accessing different regions of the /RenderTable. By having the color rendering behavior "switch" without changing the graphic state makes the implementation very fast. Since the entire implementation is limited to the Color Rendering Dictionary, dynamic CRDs may be implemented on any existing Postscript printer. Even on ones that have been in the field for years.

 

Detecting graphics in color rendering dictionaries

United States Patent 7274488 Issued September 27, 2007

Inventors: Michael Stevens

Differentiating between image and graphic objects contained within a Color Rendering Dictionary improves printing efficiency. The differentiation between image and graphic objects is accomplished by monitoring the sequence in which Color Rendering Dictionary procedures are executed. Based on the monitored sequence, an image or graphic object is determined to be used for rendering.

 

Color device profile having a buffered look-up table

United States Patent 7209145 Issued April 24, 2007

Inventors: Michael Stevens

A color device profile including a buffered color look-up table having outermost nodes that replicate nodes of an inner portion that are closest to the outermost nodes, and input tonal reproduction curves having a range that is smaller than an input range associated with the buffered color look-up table and greater than an input range associated with the inner portion.

 

Threshold encoding of frame buffers

United States Patent 7130423 Issued October 31, 2006

Inventors: Michael Stevens

A method for encoding and decoding frames by generating a key bitstream such that the key bitstream never has to be stored is disclosed. The method consists of a key generation algorithm using a threshold matrix to generate a key that is very similar to original bitmap data. The key generation algorithm searches the bitmap for equivalent image sets that produce the same bitmaps. These equivalent image sets consist of runlength of constant image values and the actual runlength. Additionally, the image values for the runlengths are never explicitly encoded. During compression a preprocess algorithm XORs the MINIMAL number of hints required to find a equivalent image value for the runlength. The postprocess algorithm is capable of distinguishing if a single bit represents an image value adjustment hint or if it represents the end of a runlength. By allowing the image value for each run length to be represented by a series of hints it is possible to avoid specifying the image value with an excessive amount of precession. Excessive precision of the image value simply adds data to the data stream without adding any additional information.

 

Text and image quality enhancement

United States Patent 6987588 Issued January 17, 2006

Inventors: Michael Stevens, Meng Yao, Mark Parker

A method to compensate for dot placement errors includes receiving image data comprising a plurality of pixels, each having at least two states, a first corresponding to depositing no ink and a second corresponding to depositing ink; identifying a stray pixel pattern within the image data, the stray pixel pattern including a stray pixel corresponding to a misplaced dot in a dot pattern; and modifying the image data corresponding to the stray pixel pattern by setting the stray pixel to the first state and changing a second pixel from the first state to the second state.

 

Color device profile having a buffered look-up table

EU Patent 1587304 Issued December 2, 2009

Inventors: Michael Stevens

A color device profile including a buffered color look-up table having outermost nodes that replicate nodes of an inner portion that are closest to the outermost nodes, and input tonal reproduction curves having a range that is smaller than an input range associated with the buffered color look-up table and greater than an input range associated with the inner portion

 

Encoding of an imaging device for generating a dynamic color rendering dictionary (Translation)

Japan Patent 4511142

Inventors: Michael Stevens

 

 

Publications

 

Defensive publication of Packed LZW Compression

June 2004

Author: Michael Stevens

 

Derivation Of 3 Dimensional Gamut Descriptors For Graphics Art Output Devices

Presented at TAGA May 1994

Author: Michael Stevens

 

 

Skills & Expertise

 

Technical Leadership

Documentation

Algorithms

C++

Image Processing

Programming

Imaging

Unix

C

Linux

JavaScript

Agile

Software Development

 

 

Education

 

Oregon State University

B.S, Physics; Engineering Physics, 1985 - 1990

Activities and Societies: Member of Sigma Pi Sigma (National Physics Honor Society)

 

 

Honors and Awards

 

Issued Patents - See Above "Patents"

 

Pending Patent Applications - 5 US published, 3 US unpublished, 1 European published, 3 Japanese published and 2 Brazilian published (US2011288854, US2011128558, US2011044535, US2010232693, US2006279753,

EP1732307, JP2006341605, JP2005295545, JP2004103017, BRPI0605317, and BRPI0602170)

 

Corporate - 11 trade secrets and 31 white papers.

 

 

Volunteer Experience

Parent Volunteer at Aloha High School

Parent Volunteer at Whitford Middle School

Parent Volunteer at Mt. View Middle School

Parent Volunteer at Errol Hassell Elementary School

Parent Volunteer at Boy Scouts of America

Parent Volunteer at Girl Scouts of the USA