Documentation – Current v5.2

Stepchart ini reference

Stepchart measures the tonal response, noise, dynamic range, and ISO sensitivity of digital cameras and scanners using

  • Reflection step charts such as the Kodak/Tiffen Q-13 and Q-14 Gray Scales, which have a single row of patches (a linear arrangement), or
  • Transmission step charts such as the Imatest 36-patch Dynamic Range Chart or charts from Stouffer, Applied Image, Kodak, DSC Labs, and Danes-Picta. Transmission charts, which have higher maximum densities than reflective charts, are required for measuring dynamic range from a single image.
  • Additional ISO charts such as ISO-14524 and ISO-15739, with non-linear (multiple rows; may be circular) patch arrangements, shown below. (Imatest Master only)

Because Stepchart is included in Imatest IT/EXE and DLL, users may need to examine or edit the INI file used to control IT versions. Stepchart settings are stored in the [q13] section of the ini file. [q13] is an old name that has been kept only for backwards compatibility— in Imatest 1.0 the module now called Stepchart analyzed only the Q13 and Q14 charts.

Most of the settings in the [q13] section are set by the Stepchart window. A few are set by responses to other windows or user actions.


Stepchart settings window

INI file settings that affect several modules are described in Imatest INI Reference.

Notes
(-IT) Not used in Imatest IT
(gr) Affects graphics (figures). May not be of interest for Imatest IT, where graphics is often suppressed.
(index) Setting is equal to the index of the popup menu. You’ll need to open the Settings window to see these: Never used for important IT settings.
(index-1) Setting is equal to the index of the popup menu – 1 (0 – (index-1)). Keeps backwards compatibility for some settings that were originally 0 (off) or 1 (on), but had options added.

Set in Blemish detect settings window
ρ
Set during image read or region selection
σ Set in Save results window

Set in other window

Table of [q13] settings

Parameter Typical values
[default]
Description Notes
ITEtype      
Lastfile      
Lasttype      
Refile      
Refolder      
altchart      
altchartype      
autopatch      
bayeraw      
chart_value      
closefigs      
distort      
figsave      
filecomb      
fillf      
folder      
roi 899            950           3029           1124           3029            950            899           1124

ROI (Region of Interest) for last n images: 8 numbers per image corresponding to the widths and heights in the nwid_save and nht_save variables.

These 8 numbers define 4 corner ponts of a Quadrilateral which can be used to adjust for rotation and keystone distortion.  

Order of variables:  

#1: X(tl)  #2: Y(tl) #3: X(br) #4: Y(br)  

#5: X(tr)  #6: Y(tr) #7: X(bl) #8: Y(bl)

 

Sample data

[q13]
 = 0.6            0.6           0.65           0.65
= C:ImatestDataClass_examplesColor_stepchart_examples
fstmax_string = Auto
fstmax_value = 1
fstmin_string = Auto
fstmin_value = 1
iso15739type = 1
lastdens = 0.1           0.19            0.3           0.41           0.53           0.66           0.81           0.97           1.17           1.39           1.66              2           0.77            0.9           1.05
lastfiles = “GF1_ColorStep_4700K_45mm_f8_i100_1030244.JPG”
linfixp = 1
luxinc = 220
mirror = 0
mxn = 4              6
nht_save = 3000            480            271            237
noisenorm = 5
noiseres = 2
nonualgorithm = 1
nonucorr = 0
nonufile =  
nonugamcolsp = 0
nonugamma = 0.5
nonulevel = 1
nonusave = 1
nwid_save = 4000            640           2710            862
oecf20type = 1
plot2lux = 1
plt_fstopn = 2
pltallch = Max
pltemporal = Max
pltnoise = Max
pltpix = Max
progm = Stepchart
progmalt = ISO-15739 standard 80:1
ref_value = 1
resultsave = 1
roi = 977            998           3054           1189           3054            998            977           1189            140             88            477            381            477             88            140            381             26              1           2710            271           2710              1             26            271             30            124            839            213            839            124             30            213
satlvl = 1
saveCSV = 1
saveJSON = 1
saveXML = 0
save_answer = No
save_dir = C:ImatestDataClass_examplesColor_stepchart_examplesResults
save_file_list = 1  1  1  1  0  0  0  1  0  0
stepatch = 20
vglare = 0
whitebal = 1
xmin_string = Auto
xmin_value = 1