United States 

Department of 

Agricuxture - 

&rest Service 

Southern. 

R~~~~ ch Station 

Generd Technical 

Report 5X-93 

Users Guide for Fire Image 

Analysis System-Version 5.0: 

A Tool for Measuring 

Fire Behavior Characteristics 

Carl W. Adkins 
The Author: 

Gar3 W. Adkins is a Scientific and Technical Photographer with the 

USDA Forest Service, Southern Research Station, Southern Forest Fire 

Laboratory, Dry Branch, GA 3 1 020. 

September 1995 

Southern fiesearch Station 

P.O. Box 2680 

Asheville, NC 28802 
Users Guide for Fire Image 

Analysis System-Version 5.0: 

A Tool for Measuring 

Fire Behavior Characteristics 

Carl W. Adkins 

Contents 

htroduction ..................................................... 1 

System Overview ................................................ 1 

Arrangement of the User's Guide .................................... 1 

Systemconcept .................................................. 1 

System Resolution ................................................ 2 

Getting Started .................................................. 2 

Hardware Requirements ........................................... 2 

Image Capture ................................................. 2 

Image Analysis ................................................. 2 

Hardware Configuration ........................................... 3 

Loading Software ................................................ 3 

Image Capture .................................................. 4 

Recording the Fire ............................................... 4 

Calibrating ..................................................... 5 

Examples of Field Setup ........................................... 5 

Pre-Fire Field Calibration ........................................ 5 

Post-Fire Field Calibration ....................................... 6 

Sloped Terrain ................................................. 7 

ImageAnalysis ................................................... 7 

StartingUp ..................................................... 7 

The Methods .................................................. 8 

TheBasics ................................................... 10 

Function Keys ................................................ 10 

Still and Play Modes ........................................... 10 

Adjusting and Calibrating the Image Analysis System .................. 10 

Video Adjustment ............................................. 10 

System Calibration ............................................. 11 

Operating the System ............................................ 12 

Digitizing Flames .............................................. 12 

Point Input Considerations ...................................... 12 

Creating and Saving Data ....................................... 12 

Deleting Data ................................................. 13 

Viewing and Printing Data ...................................... 13 

Plotting Data ................................................. 13 

Sampling Flame Images .......................................... 15 

Additional Operations ........................................... 15 

Rate of Fire Spread .............................................. 15 

Exporting Data into Other Programs ................................ 15 

Literaturecited ................................................. 15 

Abstract 

The Fire Image Analysis Systern is a tool for quatltaing flame geometry and 

relative position at selected points along a spreading line fire. At present, the 

requires unifom terrain (constant slope). The system has been used 

in field and laboratory studies for determining flame length, depth, cross 

sectional area, and rate of spread. 

Keywords: Flame length, quantifying flame geometry, rate of spread. 

System application is limited to line fires burning in even 

terrain (flat or uniformly sloping) where the camera's field of 

view is unobstructed. The camera must be positioned normal 

(right angle) relative to the direction of fire spread to ensure 

the profile of the flame is presented to the camera's field of 

view. System accuracy depends on careful adherence to 

prescribed methods for setup and calibration in the field and 

digitization at a workstation. 

Introduction 

The behavior of wildland fire is recognized as important in 

formulating control strategies for wildfire and in using 

prescribed fire. Research and operational personnel use 

behavior characteristics, such as visually apparent flame 

length, flame angle, flame depth, and the rate of spread of a 

fire front, when they evaluate fire behavior and fire effects. 

The Fire Image Analysis System provides a record of these 

fu-e attributes as video image replicas that can be measured in 

the image analysis subsystem. 

System Overview 

The system is comprised of two elements, image capture and 

image analysis. Images are captured with a S-VHS video 

camera equipped with a character generator for on-screen 

display of elapsed time. The image analysis subsystem is a 

personal computer-based system that can display video stillframe images of flames from a S-VHS video recorder and 

digitize selected points interactively. Values for flame height, 

depth, length, cross-sectional area, position, and distance 

from the camera position are calculated from selected point 

locations. Time annotation for each frame of video and the 

position of the flame front permits calculation of the rate of 

spread. 

A field reference range target is used to calibrate video 

picture elements into English or metric units of measure. The 

system's unique ability to rescale objects at distances other 

than the calibration reference point (range target) is an 

important feature because the nature of spreading line fires is 

unpredictable. Although wind-dnven line fires tend to spread 

with an elliptically shaped fire front, conditions at the bum 

site often cause the fire's leading edge to advance in a 

nonuniform way. Different segments of the line will often 

dominate and advance at a higher rate of spread than other 

segments, causing the measurement point to shift forward 

toward the camera position or away from the camera position 

relative to the calibration reference point. Because the 

distance has changed, the system must be rescaled. 

Arrangement of the User's Guide 

This user's guide is arranged to facilitate the following 

activities: 

1. Understanding the general concept and operations of the 

system, 

2. Selecting and setting up system hardware, 

3. Loading the software, 

4. Recording the fire images, 

5. QuantIrLing the recorded images in terms of fire behavior 

characteristics, and 

6. Performing additional analyses and operations. 

System Concept 

The basic concept of the Fire Image Analysis System is 

illustrated in the following example: 

In figure 1, a line fire is burning over a level, grass plain with 

a railroad track bisecting the observer's field of view. A cross 

section of the fire is shown because all measures of flame 

geometry are based on that perspective. The fire is advancing 

from left to right, toward the track. Because the rails of the 

track are parallel and the width between them is known, the 

observer can scale the dimensions of the fire by comparing it 

to the width of the rails at any given point along the track. 

In the Fire Image Analysis System, a S-VHS video camera is 

substituted for the observer. An interactive system, where the 

images of the fire are overlaid with computer-generated 

graphic aids for measurement, is used to scale and measure 

the video images. In the image analysis process, the railroad 

track is represented as triangle A, B, C in figure 2; a single 

rail tie is the baseline, and the rail segments diminish into 

infinity. In the system, the user is able to adjust the position 

of the baseline (rail tie) and rescale the system to that 

distance. Once the system is rescaled, points on the flame are 

digitized using the mouse. After these points are entered (1, 

2,3,4 in fig. 2), the system processes the measures of flame 

geometry and displays that information automatically. 
30 PIXELS 

One pixel = ,183 feet 

Figu~e 1-The system scaling concept is illustrated using the width between 

parallel railroad tracks. Objects can be scaled at any distance along the 

tracks by comparing their dimensions to the width between the rails at the 

same distance. 

I , Workspace Frone I 

Figure 2-Elements of the computer generated video overlay workspace and 

graphic measurement aids using the four-point option for digitizing flame. 

System Resolution 

The system resolution is a function of the horizontal and 

vertical resolution of the hardware and the distance of the 

plane of measurement to or fi-om the calibration distance at 

the range target. The hardware resolution is defined by the 

total number of picture elements (pixels) in the horizontal 

(629) and vertical (1 89) area of the video workspace. The 

baseline location controls scale and determines how many 

pixels represent a given distance in space (fig. 1). The 

number of pixels decreases for the same horizontal measure 

of length as distance fi-om the camera increases. The pixel 

sizes are exaggerated for clarity. 

Getting Started 

Hardware Requirements 

Image Capture 

1. Panasonic S- VHS camcorder model No. AG-450 1 0: 1 

zoom lens with standard accessories 

2. Panasonic character generator for No. AG-450 camcorder, 

model No. VW-CG1 

3. Panasonic battery pack 1 2 2.3 AH, model No. AG-BP2 1 2 

Image Analysis 

1. Computer-AT 486 or 3 86 with 3 87 math co-processor, 

3 - 112-inch and 5- 114-inch high density floppy drives, 80 MB 

hard drive, and mouse 

2. Panasonic S-VHS 112-inch cassette recorderlplayer with 

digltal frame memory, model No. AG-73 55' 

3. SONY Trinitron color video monitor 20-inch (RGB) super 

fine pitch model No. PVM-2030 

4. Magitronics super VGA 1024 X 768 14-inch color 

monitor Luiski International part No. A-SV1448 

5. Magitronics super-VGA graphcs adapter with one meg 

RAM non-interlaced Luiski International part No. 

A-VGA422 

6. SciMeasure color graphics interface board with S-VHS 

chroma decoder, P/N SCI-CGB 

7. SciMeasure color graphics generator board P/N SCICGGB 

8. Hewlett Packard Laser Jet TV printer 

The Panasonic S-VHS model No. AG-7355-P has digital be memory 

that improves still &me image stability and allows display of either of the 

two video fields that make up a video he. This feature has a number of 

benefits. By digitally storing the image, the mechanics of the rotating tape 

head are disengaged which preserves the tape, and displaying only one field 

per frame improves time resolution. Time resolution is increased because a 

video he (1130 second duration) is made up of two fields (1/60 second 

each). 
Hardware Configuration 

/ KEYBOARD 1 u VIDEO TAPE RECORDER 

Figure 3-Schematic diagram of the Image Analysis Hardware and hardware connections. 

Loading Sohare 

Installing the entire system f?om the floppy disk to the hard 

disk will require some familiarity with the MS-DOS operating 

system (the base operating system for the Fine Image Analysis 

System). Instructions for this procedure follow: 

1. Exit any currently running software to return to the DOS 

prompt. 

2. Change to the root directory of the desired disk. 

3. If installing the system for the first time, make 

subdirectories to hold the FAS files and the data. An example 

follows: 

[C :\]md fas 

[C :\]md fastdata 

[C:\I_. 

4. Copy the files on the supplied disk (if on the B: floppy 

drive) to the C: hard drive: 

[CAI copy b:*.* FAS 

5. First-time software installation requires a few changes to 

the AUTOEXEC.BAT file. The line in the 

AUTOEXECBAT that begins with PATH must be modified. 

Using a text editor, open the file C:\AUTOEXEC.BAT. Then 

append the following to the last PATH command: 

;C:WAS 

so that PATH=C:V>OS 

will become PATH=C :DOS;C : WAS 

To print graphics, the DOS GRAPHICS utility must be 

installed. If the command GRAPHICS does not appear on 

any line in the AUTOEXEC.BAT file, it must be added: 

PATH=C:DOS;C:WAS 

GRAPHICS 

If the user has anmng other than a standard dot matrix 

printer, the DOS manual on using GRAPHICS utility should 

be consulted. For example, lf using an HP Laserjet I1 or 

higher laser printer, the following GRAPHICS command 

would be added: 

PATH=C:V>OS;C:\FAS 

GRAPHICS LASERJETII 
To print a graph from within the program, simply press 

<Shift>- print screen> 

To run the FAS soilware automatically when the system 

boots, the last line in the AUTOEXEC.BAT file must appear 

as follows: 

RUNFAS 

Once the new AUTOEXXBAT file has been saved, reboot 

the computer to load and activate the changes. 

6. To run the FAS soilware, type: 

[c:\FAS] RUNFAS 

Image Capture 

Recording the Fire 

The process of collecting accurate data with the image 

analysis system begins with the proper placement, alignment, 

and calibration of the video camera. In documenting field 

fires, the frrst step is to locate an area of interest in the 

prospective burn as near a plane surface as possible. The 

area can be flat or uniformly sloping. Figure 4 illustrates a 

typical situation for flat terrain. Although some minor relief is 

shown for practical purposes of measurement, the surface is 

considered flat. 

Once the area of interest is selected, camera placement 

depends on wind direction. The camera's line of sight should 

\ 

OPTICAL 

-- 

LEVEL 

-- -

be as close to a right angle (nomal) to wind direction as 

possible. Proper placement will show a line fire moving from 

left to right or right to left in the camera's viewfinder. 

The right angle relationship of the camera's line of sight to the 

wind direction (direction of frre spread) provides two possible 

camera positions. For example, consider the direction of fire 

spread as vector 0" and the direction that the fire is spreading 

from as vector 180". A camera positioned at a right angle to 

the fire spread would be at either 90 or 270". Selecting a 

camera position between the two possibilities is based on the 

direction and angle of the sun. The camera should be 

positioned so the smoke from the fire is not back lit and direct 

sunlight does not strike the camera lens. In both cases, the 

video image will be degraded by light flare mhg it difficult 

to distinguish flames. 

Back lighting of the smoke and direct sunlight striking the 

lens occur when a low solar angle is present. Although 

problems with low solar angle are most pronounced in early 

moming and late afternoon during the winter months, 

problems can also be encountered early moming and late 

afternoon during the summer months. 

Next, the camera's line of sight is adjusted parallel to the 

ground-level datum by using an optical leveling device such 

as an Abney level or clinometer. Using a range target of 

known height above the ground level datum, the camera 

height is raised or lowered to intersect the level line sighted 

with the optical leveling device on the range target upper 

marker (fig. 4). From a slight distance behind the camera, 

FIELD SETUP FOR CAMERA AND 

REFERENCE MARKER 

LEVEL DATUM OF 

---- 

GROUND LEVEL DATUM 

HORIZON 

Figure 4-Using an optical leveling device, such as an Abney level or clinometer, the camera is raised or lowered so the center line axis 

of the lens intersects with the level datum of the virtual horizon. The height of the level datum above the ground level is measured at the 

refetence marker, in the illustration the height is 1.69 meters. 
this optical leveling device sights a level line to the center of 

the top marker and the lens is brought to that level. The 

center of the top marker is considered the virtual horizon; that 

is, the point where the ground level datum and the level datum 

at the center of the top marker converge at the horizon. 

After the camera height is set, the target is centered in the 

viewfinder by tilting the camera upward or downward. Field 

tests have shown that a camera level of 5 feet above the fuel 

layer is adequate for flame positions 80 to 150 feet fi-om a 

camera with its lens set to the maximum wide-angle focal 

length. For flame positions at greater distances, the camera 

should be raised 5 feet for every 100 feet of distance. In 

situations where the height of the camera or the fuel depth is 

greater than eye level, a ladder is used as a camera mount. 

Finally, the proposed burn is named (ID). Fire ID'S are 

limited to eight characters to conform to the MS-DOS 

operating system. 

Calibrating 

Figure 5 shows an example of the range target ~o~guration. 

The target is also used to establish vertical and horizontal 

length references for calibration in the image analysis process. 

The target is constructed of four markers separated by fixed, 

measured distances. The height of the target is adjustable to 

suit different fuel depths and distances of points of interest 

along the fre line. 

Examples of Field Setup 

Re-Fire Field Calibration 

1. An area in a palmetto-gallbeny fuel type has been 

designated for a prescribed burn. The burn is a headfire in 

flat terrain. The wind is from the west and the sun is at a low 

winter position to the south. In this situation, a camera 

CENTER CURSOR 

WHEN DITIGIZING 

I GROUND LEVEL 

DIRECTION OF- FIRE SPREAD 

Caiibration Sequence 

Figure 5-The range target with the markers labeled 1 through 5 shows the sequence used in system calibration when the direction of fie spread is 

lefi to right. The location for digitizing the vertical and horizontal calibration is also shown. 
position south of the burn area is selected for two reasons: 

First, the camera's line of sight will be at a right angle 

(normal) to the wind direction; second, the sun to the rear of 

the camera will eliminate flare. 

3. Raise the camera lens to the level datum again using the 

optical level to establish a level relationship to the mark on 

the wall. 

2. The camera is mounted on a tripod in a line-of-sight right 

angle to the wind direction. A range target is moved into the 

bum area along the camera's line of sight and placed at the 

approximate center of the field of view, with the center of the 

top marker raised to 5 feet above the he1 surface. 

4. View the wall through the camera's view finder and tilt the 

camera up or down to center the mark on the wall to the 

center of the view finder. Recheck the height of the camera 

lens using the optical level to the point marked on the wall to 

assure that the lens is at the level datum. Repeat the process 

until you are assured that both the camera lens (at center) is at 

the level datum height, and the mark on the wall is centered in 

the view finder. 

3. The height of the camera is adjusted to the level datum; 

that is, the height of the center of the top marker of the range 

target (virtual horizon). 

5. Using the horizontal mortar joint between the brick or 

block as a guide, level the camera horizontally in the view 

finder. 

4. Once the camera is aligned, recording begins and 

information is fed onto the audio track. An D for the fire and 

values for the distance between the horizontal and vertical 

markers at their center point on the range target, the distance 

from the range target to the camera lens, and the height of the 

center of the marker at the level datum on the range target 

aboveground level are recorded. After the calibration data is 

recorded, the camera is placed in standby mode or turned oE 

until the fire is taped. 

5. To record the fire, the camera power is turned on, which 

also powers up the character generator that displays the 

stopwatch timer in the camera's viewfinder. Adjustments for 

focus and exposure are made, and the stopwatch is displayed 

by pressing the display control button on the character 

generator. A quick check will ensure that the camera is 

recording and that the stopwatch is running. When the fire 

has traversed the field of view, the stopwatch and camera are 

turned off. This completes the data collection phase. 

Post-Fire Field Calibration 

The camera may be calibrated for field setup after the fire has 

been recorded if the camera is leveled before taping begins. 

The addition of a circular bubble level to the camera body is 

required for aligning the focal plane vertically and 

horizontally. The method for attaching the level to the body 

follows: 

1. Locate a brick or block building that has an unobstructed 

wall face. With the camera mounted on a tripod, position the 

camera 60 to 80 feet from the wall, perpendicular to the 

center. 

2. Using an optical level, establish and mark a level position 

on the wall approximately 4 feet aboveground level. 

6. Locate an area on the top of the camera body to attach the 

bubble level. Place the level in position on the camera body 

and check the position of the bubble. If the bubble is centered 

in the level circle, a light coat of epoxy cement may be 

applied and the level set into place. Once the level is 

cemented into place, recheck to ensure the bubble is in the 

center of the level circle. In the event that the bubble is not 

centered, a deeper bed of cement will allow adjustment to the 

level that will center the bubble. When the bubble level is 

mounted and cured, the camera can be set up; and the fires 

recorded. 

The post-burn method is similar to the pre-burn field setup 

and calibration; however, in this method, the range target 

marker that represents the level datum is raised to the level 

datum rather than the camera. The post-burn calibration 

setup procedure for the same conditions described for preburn field calibration follows: 

1. Position the camera normal (right angle) to the wind 

direction, adjust the field of view to the bum area, and level 

the camera using the bubble level mounted on the camera 

body. 

2. Just before the fire enters the field of view, turn on the 

camera and start the stopwatch timer. 

3. After the fire passes the field of view, stop recording but 

do not turn the power off or move the camera. 

4. Move the range target into the center of the camera's field 

of view. Using the optical level, raise or lower the range 

target until the center of the upper marker is level with the 

camera lens, which is accomplished by sighting the level from 

the camera at lens height. 
5. Video the range target and enter the calibration 

domation on the audio track for the distance between the 

horizontal and vertical markers at their center point, the 

distance &om the camera lens to the target, and the height of 

the center of the level datum marker aboveground level. Ths 

step completes the procedure, and the camera can be turned 

off. 

Sloped Terrain 

The only basic difference in the field setup between sloped 

and flat terrain is camera setup. The line of sight is across the 

slope. This relationship can be shown in the example of flat 

terrain if the area of the burn is tilted using the base of the 

range target pole as the axis of tilt (fig. 6). 

Image Analysis 

Starting Up 

Once the hardware has been properly configured, the sofhare 

loaded, and a fire captured on tape, selected image replicas of 

the flames can be transformed into measures of angle, 

position, length, height, depth, and area. If the system boots 

automatically, the user simply turns on the power. Otherwise, 

the user must boot the DOS operating system and type 

RUNFAS at the DOS prompt. When the system has loaded, 

the following menu will appear: 

USDA SFFL Image Analysis Promam Version 5.0 

Current Units are : Feet 

Select option: 

1 - Digitize Fire Behavior (Contour) 

2 - Digitize Fire Behavior (Point to Point) 

3 - Digitize Fire Behavior (Four Point) 

4 - Plot a Data Set 

5 - View a Data Set 

6 - Print a Data Set 

7 - Changeunits 

8 - Quit 

Enter option -+ 

After allowing the system to warm up for approximately 10 

minutes, the user must select the correct units of measure. To 

change the units-feet or meters-the user must press the 

No. 7 key. This key is a toggle and will return to the previous 

setting when pressed a second time. After selecting the units 

of measure, the user must decide which method to use in 

digitizing the flames and press the appropriate key. Three 

digitizing options are offered: contour, point to point, and 

four point. 

/ Range Target 

Figure 6-When using the system on sloping terrain, the base of the range target is the axis of rotation. 

The system establishes this point from the input of the virtual horizon. 
The Metho& 

Contour method (fig. 7). In this method, the user defmes the 

flame shape by tracing the outline of the flame image with the 

system mouse. From this input, the computer defmes flame 

length as the distance between the midpoint of the flme base 

and the highest point on the flame. The angle of an 

interpolated line between these points is the flame angle. This 

method is consistent with the classic def~tion of flame length 

and angle. The contour method also provides a measure of 

the cross-sectional area of the flame. Additional information 

on relative position, height, depth, range (distance &om the 

camera), contour length, and the slope of the terrain are given 

for each flame measured. 

Two-point method (fig. 8). This method requires only two 

user-defmed points. Using the mouse, one point is entered at 

the midpoint of the flame base; the other at the flame tip. This 

option allows the operator to follow the flame stream lines 

&om the origin at ground level to flame tip. This method is 

faster than outl~g the flame in the contour method but has 

several draw backs-no value for flame depth or crosssectional area is given. In addition, the relative position for 

the flame is given for the midpoint, not the leading edge. 

Four-point method (fig. 9). This method is similar to the 

contour method in parameters measured. However, in this 

method, an idealized shape far the flame is &a& &om the 

input of four points, and no value for contour length is given. 

Using the mouse, the four user-defmed points are entered: 

midpoint of the flame base, flame tip, and leading and trailing 

edges of the flame. This method is recommended based on 

experience with the system. 

The Basics 

When the digitizing method has been selected, the following 

menu will appear: 

DATE 044 3/94 

DIGITIZE FIRE BEHAVIOR - 4 POINT METHOD Trbf.l3 

FILE 

X Scale Factor =**N/A** &pixel Fl ADJUST VIDEO F2 

Y Scale Factor = ** N/A ** &pixel F3 F4 

Z Range =**N/A** n? F.S F6 STEL 

Z Correction Factor = ** N/A ** F7 F8 PLAY 

A Angle of Slope =I ** N/A ** Deg F9 F10 EXIT 

X = 320.0000 Y = - 100.0000 Z = 1.0000 MODE = CURSOR 

. 

DIGITIZE: TRAILING END OF HORIZONTAL 

*** CALIBRATION SEQUENCE - HIT <Ex.> TO QUIT *** 

At this point, the f~st-time user should become familiar with 

this interactive system. The user controls or responds to 

requests by pressing a key or working with the system mouse. 

Function Keys 

Within the double-line frarne of the menu are several areas of 

single-line fi-amed areas. At the right of the frame, two 

columns are displayed. The left column is the odd sequence 

numbered F 1 through F9; the right is the even sequence F2 

thru F 10. These F-numbers represent function keys on the 

keyboard and when labeled are active options that control 

system functions for adjusting the video image and hardware, 

handling data tasks, and exiting to the system main menu. 

Still and PIay Modes 

Before attempting to adjust, calibrate, or operate the system, 

the user should understand the two system modes of 

operation-play and still. Using the F8 function key, the play 

mode is set to view a tape in the standard play mode. The still 

mode is set with the F6 function key to view the tape in the 

still play mode or to use the digital frame memory on the 

video cassette recorderlplayer. If the recommended 

equipment described in Hardware Requirements is used, the 

system may be operated solely in the still mode. 

Adjusting and Calibrating the Image Analysis System 

The proper functioning and accuracy of data from the image 

analysis system requires adjustment to the hardware and 

calibration of the soffware. Adjustments to the hardware 

primarily involve synchronizing the computer-generated 

workspace and attendant graphics with the still fi-ame video 

images of flames. The system programming (software), 

which sets scaling algorithms for the display screen picture 

elements (pixels), must then be calibrated to the specific 

input. 

Video Adjustment 

A tape is inserted into the video tape recorder, and the section 

of the tape containing the image of the range target is located. 

After locating the target, the tape is stopped and viewed in the 

still fi-me mode. Press the digrtal fi-me memory button, and 

the image will reappear. The selection between fields 1 and 2 

should be made now. Selection is based on image stability. If 

the system is new and has never been adjusted, the image of 

the rectangular workspace frame will probably jitter and be 

oE-center. To correct this problem, press the F6 key and then 

the F 1 function key (adjust video). 
The left and right arrow keys control the centering; the up and 

down arrow keys control the wcho&ation and are used to 

eliminate frame jitter. Men satisfied with the adjustment, 

press F3 to save the settings. An additional option in the 

"adjust video" mode allows the user to change the color of the 

workspace and attendant graphic aids. Color can be used to 

provide contrast between the graphics in the digitization 

process and the image of the fire and its surroundings. The 

page up and page down keys control color, and the stepwise 

process of changing colors repeats the selections once all 

options have been stepped through. To exit the "adjust video" 

mode and access the calibration mode, press the F 1 key. 

System Calibration 

The system must be calibrated for horizontal and vertical 

length, distance from the range target, and point placement of 

the virtual horizon for each digitized fire. The calibration 

process is the same for all three methods of flame digitization. 

The user is prompted by instructions for each step of the 

process on the text monitor. As a fail-safe feature, the 

calibration must be done any time the system is exited and 

reentered. The steps in system calibration follow: 

1. Play the section where the calibration information is 

recorded on the audio portion of the tape and note the length 

of the vertical and horizontal markers, height of the virtual 

horizon, and distance from the camera to the range target. 

2. Play the tape and determine which direction the fire is 

moving-left to right or vice versa. 

3. Find the section of the tape with the range target using the 

search feature on the recorder and press the digital frame 

memory button to freeze the fi-ame in digital mode. 

4. Horizontal length will be calibrated f~st. The instruction 

"DIGITIE TRAILING END OF HORIZONTAL 

REFERENCE" is now displayed on the lower half of the text 

monitor screen, below the system menu. The trailing end of 

the reference is the center of the horizontal marker (on the 

range target) that is closest to the fire's origin. For example, 

in figure 5 the fire is spreading from left to right; therefore, 

horizontal marker 1 is closest to the fire's origm. To digitize 

the center of the target, move the mouse to center the cursor 

over the image of the trailing end marker and press the right 

mouse button. If properly entered, a white dot will appear in 

the dead center of the marker. 

5. The screen instruction changes and now reads "DIGITIZE 

LEADING EDGE OF HORIZONTAL REFERENCE." The 

leading edge of the horizontal reference is the horizontal 

marker (on the range target) farthest from the fire's origin; 

therefore, opposite the trailing marker (fig. 5, No. 2). To 

digitize this point, center the cursor on the marker and press 

the right mouse button. 

6. The screen instruction should now read "ENTER THE 

LENGTH OF THEi HORIZONTAL REFERENCE." The 

length of the horizontal reference is distance (in feet or 

meters) between the points entered in steps 4 and 5. After 

this value 1s typed and the enter key is pressed, the system is 

calibrated for horizontal measurement. 

7. Verticle length will be calibrated next, and the screen 

instruction on the text monitor should read "DIGITIZE TOP 

END OF VERTICAL REFERENCE." The procedure is the 

same as that used for horizontal calibration, except that the 

upper and lower markers on the range target are used. Locate 

the mouse cursor at the center of the upper marker (fig. 5, No. 

3); press the right mouse key. 

8. The screen instruction changes to read "DIGITIZE 

BOTTOM END OF VERTICAL REFERENCE." Using the 

mouse, enter a point at the center of the lower marker (fig. 5, 

No. 4). 

9. The screen instruction now reads "ENTER THE LENGTH 

OF VERTICAL REFERENCE. " The length of the vertical 

reference is the distance between the center point digitized on 

the upper marker and the center point digitized on the lower 

marker. To calibrate for vertical measurement, type the value 

(in feet or meters) and press enter. 

10. "DIGITIZE A POINT ON THE VIRTUAL HORIZON 

now appears on the text monitor screen. This point coincides 

with the level datum that was established in the field 

calibration of the camera. The center of the upper vertical 

reference represents this point (fig. 5, No. 5). Using the 

mouse, center the cursor in the marker and press the right 

mouse button. A mark will appear to the left and right of the 

workspace frame at the same height as the point entered. 

1 1. "ENTER HEIGHT OF THE VIRTUAL HORIZON 

ABOVEGROUND LEVEL DATUM." Enter the height 

aboveground level to the point on the reference entered in 

step 10. 

12. "ENTER THI2 CAMERA TO CALIBRATION 

REFERENCE DISTANCE." Enter the distance from the 

fi-ont lens element to the range target, and the basic calibration 

is complete. 
Operating the System 

I) Flames (Three Metho& 

2. Position the cursor at the flame tip and press the right 

mouse button. 

Before flames can be measured, the baseline must be moved 

to the leading edge of the flame at ground level. This 

adjustment to the baseline location sets the system scaling to 

that distance fi-om the camera. As a system fail-safe feature, 

the baseline must be calibrated before any flame 

measurements can be made. The baseline location is 

controlled by the mouse, and the position is fixed by pressing 

the F9 function key. After the initial baseline adjustment, F9 

must be pressed again to move the baseline to another 

position and again to fix the position. 

In the case of sloping terrain, the baseline must be adjusted to 

coincide with the slope. To adjust the slope of the baseline, 

press the F9 key, then the F7 key, and adjust the baseline with 

the mouse. Working fiom the left or right end of the baseline, 

move the cursor up or down and that end of the baseline will 

follow the cursor. Once the baseline is at the proper slope, 

press F9 to fix the angle of slope. To move the baseline 

location on the slope press F9; move the baseline with the 

mouse; press F9 again to fix the position. 

Setting the baseline and, Ifnecessary, the slope are the same 

for all three methods of flame digitization. Once the baseline 

is set, the flames can be digitized, using one of the three 

following methods: 

Contour. 

1. Using the mouse, position the cursor on the leading edge 

of the flame at the baseline (ground level) and press the right 

key on the mouse to begin. 

2. Outline the flame with the mouse ending at the baseline on 

the trailing end of the flame. Do not digitize the base of the 

flame at ground level. Press the right key on the mouse to 

end. 

Twa-Point . 

1. Position the mouse cursor at midpoint of the flame base 

(the baseline) and press the right mouse key. 

2. Position the cursor at the flame tip and press the right 

mouse key. 

Four-Point. 

1. Position the cursor at midpoint of the flame base (the 

baseline) and press the right mouse button. 

3. Position the cursor at the leading edge of the flame at 

ground level and press the right mouse button. 

4. Position the cursor at the trailing edge of the flame at 

ground level and press the right mouse button. 

Point Input Considerations 

Point placement during digitizing is straightforward for the 

leading edge at ground level and the tip of the flame. 

However, point placements for the midpoint of the flame base 

and the trailing edge at ground level rely on the judgment of 

the user. The trailing edge of the flame is often obscured 

because the shape of the fire fi-ont is elliptical. To solve this 

problem, the user can interpolate the line down the trailing 

edge of the flame. Ths procedure may require digitizing the 

flame a number of times until the line represents a best fit of 

the trailing edge of the flame. 

Creating and Saving Data 

When a flame is completely digitized, the computer will 

calculate the geometry for that observation and display the 

results on the text monitor. Each observation may be saved in 

a file. Instructions are displayed on the text monitor for each 

step in creating files and saving or deleting observations in 

these files. 

The step-by-step procedure for creating and saving data to a 

file follows: 

1. After the system is calibrated and the baseline is set, but 

before the flame is digitized, press the F4 key and the 

following screen instruction will appear on the text monitor: 

"Do you wish to 1. Append to OR 2. Create a data file." 

Enter 2 to create a data file. 

2. The instruction changes on the text monitor to "Enter 

Name of recording file : . " Enter a name of no more than eight 

characters plus three characters for file extension. 

3. After the file name is entered, the instruction on the text 

monitor changes to "Enter a short description for data set : . " 

The file must be described in 40 characters or less. This 

dormation is printed as a header in the internal plot program. 

4. After a flame is digitized, press F3 to save data. 

5. The instruction "Enter Time Tag MM:SS:CC:" is 

displayed on the text monitor. This is the time taken f?om the 
screen display on the video monitor of the camera timer 

where W equals minutes; SS, seconds; and CC, hundredths 

of a second. The character generator only displays to a tenth 

of a second; thus, enter tenths followed by a zero. For 

example 1 minute, 29 seconds, and one-tenth of a second will 

be entered 0 1 :29: 10. Enter a colon between minutes, 

seconds, and tenths or hundredths of seconds. 

6. The process for digitizing and saving data continues until 

the entire fre has been digitized or complete digitization has 

been postponed. Exiting the digitizing mode closes the file. 

An append file feature has been incorporated into the system, 

which allows the user to reopen a closed file at a later time. 

This feature is also used to reopen a file to delete an 

observation. 

Delkaig Data 

The F5 key, labeled "DELETE RECORD" on the text monitor 

menu, controls the delete function in the system. However, 

the system does not allow complete file deletion, which must 

be done at the operating system level. The steps for deleting 

observations within files follow: 

1. Press the F5 key and the following instruction appears: 

"Do you wish to delete data by 1. Sample No. or 2. Time :." 

Select the option by entering either 1 or 2 and pressing return. 

2. If option 1 is selected, enter the sample number (numbers 

consecutively assigned to the observations). If the 

observation is deleted by the time tag, reenter the time tag 

assigned during the save data process. 

Rec Time F-Posn F-Hite FLen 

# Secs Ft Ft Ft 

-------------------------------------- 

1 00:57:05 -1.92 8.81 9.69 

2 00:58:70 -1.16 6.67 7.18 

3 00:59:70 -0.58 9.29 10.01 

4 01:00:70 0.20 6.83 7.56 

5 01:01:70 0.17 7.94 8.75 

6 01:02:70 0.36 5.76 7.24 

7 01:03:70 0.78 5.30 8.09 

8 01:04:70 1.26 6.79 7.89 

9 01:05:70 1.78 4.40 5.71 

10 01:06:80 3.28 7.63 9.42 

11 01:07:80 3.00 6.64 8.08 

12 01:08:80 4.42 6.96 8-73 

13 01:09:70 4.58 7.24 9.19 

14 01:10:70 4.33 6.83 8.35 

15 01:11:70 4.12 7.25 7.89 

Vdg and Printing Data 

During the digitization process, recorded data may be 

reviewed without exiting the program by pressing the F3 key. 

After viewing the data, press any key and the system reverts to 

the digitization mode. If you have exited the fire image 

analysis system, view data (No. 5) or print data (No. 6) can be 

selected fiom the fze image analysis main menu. In both 

View and Print, the data are presented in the same format 

with the time given in minutes, seconds, and tenths and 

hundredths of a second (fig. 10). In both View and Print, a 

list of the files are displayed on the screen. If you have 

accumulated more files than one screen can display, the 

remainder will scroll down the screen until it reaches the end. 

You may stop the scroll at any point by pressing the control 

key and the "s" key simultaneously. To continue, press enter 

and the file list will continue to scroll. 

Plotting Data 

It is often helpful in the analysis process to evaluate the data 

in graphic form. A simple quick plot feature in the system 

provides for cursory examination of the data in cartesian 

coordinate form. The step-by-step procedure for using the 

plot program follows: 

1. At the main menu, enter option 4, and a list of the current 

files is shown. At the bottom of the list, this instruction 

appears: "Enter Name of File to be plotted fiom -+. " Type the 

file name and press return. 

2. Once the file name is entered, the screen displays file 

information and parameters. 

F-Ang FtoCam Fslope F-Area LD 

Deg Ft Deg SqFt Ft 

----------------------------------------- 

24.64 65-48 0.00 13.96 3.17 

21.86 65.48 0.00 12.31 3.69 

21.99 65.48 0.00 19.44 4.19 

25.50 65.48 0.00 11.91 3.49 

24.95 65.48 0.00 13.61 3.43 

37.29 62.50 0.00 9.83 3.41 

49.02 62.50 0.00 10.01 3.77 

30.61 61.57 0.00 10.58 3.12 

39.55 61.57 0.00 8.55 3.88 

35.91 72.37 0.00 15.69 4.11 

34.75 64.45 0.00 14.16 4.26 

37.09 73.66 0.00 21.07 6.05 

37.97 71.12 0.00 22.18 6.13 

35.04 68.75 0.00 19.19 5.62 

23.24 68.75 0.00 17.37 4.79 

Figure 10-Example of the data format for the View and Print utilities fiom the system main menu. 

Note that the time annotation is in minutes, seconds, and tenths and hundredths of seconds. 
Data File Type is : FOUR POINT IYIETHOD 

File Description : mADFW B-AL 

Date File Created : 0 110419 1 

No of Parameters : 9 

1 Time 

2 FPosn 

3 F-Hite 

4 F-Len 

5 F-ang 

6 FtoCam 

7 Fslope 

8 F-Area 

9 FD 

Secs 

Ft 

Ft 

Ft 

Deg 

Ft 

Deg 

SqFt 

Ft 

Elapsed Time 

Re1 Position of Flame Base 

Flame Height 

Flame Length 

Flame Angle from Vert. 

Camera to flame distance 

Baseline slope 

Projected Flaming Cross Section 

Flame Depth 

Enter Number of X-axis Variable to be plotted -+2 

Enter Number of Y-axis Variable to be plotted -+4 

At the bottom of the display is the instruction "Enter Number 

of X-axis Variable to be plotted-+." The X-axis variable is 

selected by a number from the list on the display and is the 

ho~ontal axis on the graph. Enter the number of the 

parameter and press return. 

3. The instruction, "Enter Number of Y-axis Variable to be 

plotted+," is displayed next. Again, the Y-axis variable is 

selected &om the list on the display for the Y-axis and is the 

vertical axis on the graph. Type the number of the parameter 

and press return. 

4. After the X and Y parameters are selected, the screen 

changes, and the data for the axis is displayed. Press return 

again and the plot is displayed (fig. 1 1). 

5. A hard copy can be printed by pressing and holding the 

Shift key and pressing the Print Screen key. Note that the 

print screen process takes 5 minutes or longer and should not 

be considered as a primary source of plots for fire data. 

FOUR POINT METHOD - HEhDFIRE BIhNNUAL 

Flame Length us Re1 Position of Flame Base 

V 

-2.00 -1.00 8.00 1.00 2.00 3.00 4.00 5.88 

Re1 Position of Flame Base <Ft) 

Figure 11-The relationship between relative position of the fire and flame length is shown in a two-dimensional plot created by the Plot utility from the main menu. 
6. To exit from the plot, press the return key to return to the 

plot menu. 

7. To exit plot, press the return key to access the main menu. 

Sampling Flame Images 

Once the mechanics of operating the system are mastered, the 

user should concentrate on how to sample flame images. 

Typically, a number of flames are sampled from the many 

frames of video shot as the fire traverses the camera's field of 

view. Sample frequency is determined by the user, based on 

the desired information and the objectives of the study. 

However, the difference between human visual perception of 

flame and instantaneous video images (one-sixtieth of a 

second per field) should be understood before attempting to 

gather a representative sample of flame images. Ths 

understanding is crucial to representative sampling of flame 

height and length. The conventions set forth in the literature 

cite a relationship between visual estimates of flame length 

and Byram's fireline intensity for determining fire intensity 

(Rothermel and Deeming 1 980). In video analysis of flames, 

flame length varies from frame-to-frame and field-to-field and 

depends on the stage of development of the flame pulse; that 

is, flame length is not a constant but, in fact, a rapidly 

pulsating phenomenon. Experience has shown that the 

pulsation frequency varies with the intensity of the fire fi-om a 

very high frequency for low-intensity fires to a much lower 

iiequency for high-intensity fires. To an observer, the flames 

of lower intensity fires appear to flicker. In higher intensity 

fires, the pulsation frequency is low enough for an observer to 

view the flame building to a maximum length. To match the 

video data to the visually perceived flame length or height, 

only the field of video where the flame is at its maximum 

extension should be considered representative of flame length 

or height. 

Additional Operations 

Rate of Fire Spread 

Rate of spread can be calculated from the output of elapsed 

time and relative position of the fire front at two different 

positions along the direction of spread. Rate of spread is the 

traverse distance divided by the elapsed time in seconds. 

Exporting Data Into Other Programs 

The data are saved in ASCII Text format and may be exported 

to other software programs. These files are located in the 

Files subdirectory under the directory FAS. The file 

extension for all data files is .DAT (fig. 12). 

Literature Cited 

Rothermel, Richard C.; Deeming, John E. 1980. Measuring and 

interpreting fire behavior for correlation with fire effi. Gen. Tech. Rep. 

INT-93. Ogden, UT: U.S. Department of Agriculture, Forest Service, 

Intermountain Forest and Range Experiment Station: 4 p. 

Time F-Posn F-Hite FLen F-Ang FtoCam 

Sees ~t Ft Ft Deg Ft 

-------------------------------------------------- 

57.05 -1.92 8.81 9.69 24.64 65.48 

58.70 -1.16 6.67 7.18 21.86 65.48 

59.70 -0.58 9.29 10.01 21.99 65.48 

60.70 0.20 6.83 7.56 25.50 65.48 

61.70 0.17 7 94 8.75 24.95 65.48 

62.70 0.36 5.76 7.24 37.29 62.50 

63.70 0.78 5.30 8.09 49.02 62.50 

64.70 1.26 6.79 7.89 30.61 61.57 

65.70 1.78 4.40 5.71 39.55 61.57 

66.80 3,28 7.63 9.42 35.91 72.37 

67.80 3.00 6.64 8.08 34.75 64.45 

68.80 4.42 6.96 8.73 37.09 73.66 

69.70 4.58 7.24 9.19 37.97 71.12 

70.70 4.33 6.83 8.35 35.04 68.75 

71.70 4.12 7.25 7.89 23.24 68.75 

Fslope F-Area F-D 

Deg SqFt Ft ,------------------------- 

0.00 13.96 3.17 

0.00 12.31 3.69 

0.00 19.44 4.19 

0.00 11.91 3.49 

0.00 13.61 3.43 

0.00 9.83 3.41 

0.00 10.01 3.77 

0.00 10.58 3.12 

0.00 8.55 3.88 

0.00 15.69 4.11 

0.00 14.16 4.26 

0.00 21.07 6.05 

0.00 22.18 6.13 

0.00 19.19 5.62 

0.00 17.37 4.79 

Figure 12-Example of the .dat file fonnat found in the data subdiredory of FAS. In this format, time is 

expressed in seconds and &adions of second that accommodate import into database software packages. 
The computer program described in this publication is available on 

request with the understanding that the U. S. Department of Agriculture 

cannot assure its accuracy, completeness, reliability, or suitability for 

any other purpose than that reported. The recipient may not assert any 

proprietary rights thereto nor represent it to anyone as other than a 

Government-produced cornputer program. For more Somation write 

Carl W. Adkins, USDA Forest Service, Southern Forest Fire 

Laboratory, Southern Research Station, Route 1, Box 1 82A, Dry 

Branch, GA 3 1020. 

The use of trade or firm names in this publication is for reader 

Somation and does not imply endorsement by the U.S. Department of 

Agriculture of any product or service. 
The Fire Image Analysis System is a tool for quantifying flame 

geometry and relative position at selected points along a spreading 

line fire. At present, the system requires uniform terrain (constant 

slope). The system has been used in field and laboratory studies for 

determining flame length, depth, cross sectional area, and rate of 

spread. 

Adkins, Carl W. 1995. Users guide for fire image analysis 

system-version 5.0: a tool for measuring fire behavior 

characteristics. Gen. Tech. Rep. SE93. Asheville, NC: U.S. 

Department of Agriculture, Forest Service, Southern Research 

Station. 15 p. 

I Keywords: Flame length, quantifying flame geometry, rate of 

I spread. 

Adkins, Carl W. 1995. Users guide for fire image analysis I 

system-version 5.0: a tool for measuring fire behavior I 

characteristics. Gen. Tech. Rep. SE-93. Asheville, NC: U.S. I 

Department of Agriculture, Forest Service, Southern Research I 

Station. 15 p. I 

1 

The Fire 

geometry 

line fire. 

Image Analysis System is a tool for quantifying flame I 

and relative position at selected points along a spreading I 

At present, the system requires uniform 'terrain (constant I 

slope). The system has been used in field and laboratory studies for I 

I 

determining flame length, depth, cross sectional area, and rate of I 

spread. I 1 

Keywords: Flame length, quantifying flame geometry, rate of I 

spread. 1 I 
The Forest Service, U.S. Department of 

Agriculture, is dedicated to the principle of 

multiple use management of the Nation's 

forest resources for sustained yields of wood, water, 

forage, wildlife, and recreation. Through forestry 

research, cooperation with the States and private 

forest owners, and management of the National Forests 

and National Grasslands, it strives-as directed by 

Congress-to provide increasingly greater service to a 

growing Nation. 

USDA prohibits discrimination on the basis of race, 

color, national origin, sex, age, religion, or handicapping 

condition. Any person who believes he or she has been 

discriminated against in any USDA-related activity 

should immediately contact the Secretary of Agriculture, 

Washington, DC.