Stray light (flare) documentation pages
Introduction: Intro to stray light testing and normalized stray light | Outputs from Imatest stray light analysis | History
Background: Examples of stray light | Root Causes | Test overview | Test factors | Test Considerations | Glossary
Calculations: Metric image | Normalization methods | Light source mask methods | Summary Metrics | Analysis Channels | Saturation
Instructions: High-level Imatest analysis instructions (Master and IT) | Computing normalized stray light with Imatest | Motorized Gimbal instructions
Settings: Settings list and INI keys/values | Standards and Recommendations | Configuration file input
This page provides a list and description of the settings for Imatest stray light source analysis, as well as corresponding INI field-value pairs.
Page Contents
General Settings
|
Memory Mode |
How to prioritize memory use vs disk i/o during the analysis. The default is low memory mode. |
Memory Mode Enumeration |
memory_mode |
Calculation Settings
|
Calculation |
The type of stray light calculation. The default is Transmission. |
calculation |
|
|
Data Transform |
The transform to apply to the metric image(s). The default is linear (no data transform). |
data_transform |
|
|
Dark Level |
The dark level in digital numbers. The default is 0. If not known, assume 0. |
Number (Greater than or equal to 0) |
dark_level_dn |
|
Clip To One |
Enable to clip the image data to one (instead of zero). The default is false (clip to zero). Note: this control only shows up in the GUI if the Calculation is Attenuation or one of the Logarithmic Data Transforms are used. |
Boolean |
clip_to_one |
Analysis Channel Selection Options
|
Analysis Channel(s) |
The default is automatic. Note: Based on the option selected, additional inputs may be required. |
channel_type |
|
|
Luminance Channels |
The standard to use for computing a luminance channel. The default is IEC 61966-2-1. Note: This option is used only if the Analysis channels are either Luminance or RGB + Luminance. |
channel_lum_type |
|
|
Custom RGB Weights
|
The custom red, green, and blue weights for computing a luminance channel. This option is used only if the Analysis channels are either Luminance or RGB + Luminance, and the Luminance Channels are Custom. |
Array of 3 numbers |
channel_lum_custom_rgb_weights
|
|
RGB Order |
The ordering of the RGB channels. The default is RGB. Note: This option is used only if the Analysis channels are either RGB or RGB + Luminance. |
channel_rgb_order |
|
|
Statistics |
The statistics to use. The default is Mean. Note: This option is used only if the Analysis channels are Statistics. |
channels_stats_type |
Saturation Calculation Options
|
Method |
The method for calculating the saturation level. |
Saturation Method Enumeration |
saturation_method |
| Bit Depth |
The user-provided saturation in bits. Note: This option is only used if the saturation method is “Specify Bit Depth”. |
Number | saturation_user_bit_depth |
| Value |
The user-provided saturation in digital numbers. Note: This option is only used if the saturation method is “Specify Value”. |
Number | saturation_user_value |
Normalization Options
|
Normalization Method |
The type of normalization to perform. The default is None. Note: Based on the option selected, additional inputs may be required. |
normalization |
Level Normalization Options
The following options apply if the normalization method is Level. See the normalization page for a description of the Level normalization method.
|
Normalization Level |
The normalization level in units of digital number (DNs). The default is 1 (same as None normalization). |
Number (greater than 0) |
norm_level_value |
Direct Reference Image Normalization Options
The following options apply if the normalization method is Direct Reference Image. See the normalization page for a description of the Direct Reference Image normalization method.
|
Image Filename |
The fully-qualified path to the reference image. |
Path to a valid image file |
norm_refim_filename |
|
Normalization Aggregation |
The methodology for aggregating the detected source pixels into a normalization factor. The default is Median. |
norm_refim_aggregation |
|
|
ND Measurement Type |
The type of neutral density (ND) measurement used for the reference image capture. The default is None. |
norm_refim_comp_nd_type |
|
|
ND Density Value |
The density of the neutral density filter(s) used for the reference image capture. Used if ND Measurement Type is set to ND Density. The default is 0 (no ND filter used). |
Number (greater than or equal to 0, less than or equal to 100) |
norm_refim_comp_nd_density_value |
|
ND Transmission Value |
The transmission percentage [0-100] of the neutral density filter(s) used for the reference image capture. Used if ND Measurement Type is set to ND Transmission. The default is 100 (no ND filter used). |
Number (greater than 0, less than or equal to 100) |
norm_refim_comp_nd_transmission_value |
|
Integration Time Ratio |
The ratio of the reference integration time to the analysis integration time (i.e., value for reference image divided by value for analysis image). The default is 1 (test and reference images have the same integration time). |
Number (greater than 0) |
norm_refim_comp_int_time_ratio |
|
Gain Ratio |
The ratio of the reference gain to the analysis gain (i.e., value for reference image divided by value for analysis image). The default is 1 (test and reference images have the same gain). |
Number (greater than 0) |
norm_refim_comp_gain_ratio |
|
Light Level Ratio |
The ratio of the reference light level to the analysis light level (i.e., value for reference image divided by value for analysis image). The default is 1 (test and reference images have the same light level). |
Number (greater than 0) |
norm_refim_comp_light_level_ratio |
Lambertian Reference Image Normalization Options
The following options apply if the normalization method is Lambertian Reference Image. See the normalization page for a description of the Lambertian Reference Image normalization method.
|
Image Filename |
The fully-qualified path to the reference image. |
Path to a valid image file |
norm_lrefim_filename |
|
Normalization Aggregation |
The methodology for aggregating the detected source pixels into a normalization factor. This setting can only be set in the INI. The default is Median. |
norm_lrefim_aggregation |
|
| Light Measurement Type |
The type of light measurements made. The default is radiometric. Note: The choice of this value impacts other measurement inputs. |
Light Measurement Type Enumeration |
norm_lrefim_source_meas_type
|
| Radiance from Lambertian Diffuser |
The measured radiance from the Lambertian diffuser for the reference image. Note: this option is only used if the Light Measurement Type is Radiometric. |
Number (greater than 0) |
norm_lrefim_ref_radiance
|
| Irradiance at the camera location |
The measured irradiance at the camera location for the test image(s). Note: this option is only used if the Light Measurement Type is Radiometric. |
Number (greater than 0) |
norm_lrefim_irradiance
|
| Luminance from Lambertian Diffuser |
The measured luminance from the Lambertian diffuser for the reference image. Note: this option is only used if the Light Measurement Type is Photometric. |
Number (greater than 0) |
norm_lrefim_ref_luminance
|
| Illuminance at the camera location |
The measured illuminance at the camera location for the test image(s). Note: this option is only used if the Light Measurement Type is Photometric. |
Number (greater than 0) |
norm_lrefim_illuminance
|
|
Integration Time Ratio |
The ratio of the reference integration time to the analysis integration time (i.e., value for reference image divided by value for analysis image). The default is 1 (test and reference images have the same integration time). |
Number (greater than 0) |
norm_lrefim_comp_int_time_ratio |
|
Gain Ratio |
The ratio of the reference gain to the analysis gain (i.e., value for reference image divided by value for analysis image). The default is 1 (test and reference images have the same gain). |
Number (greater than 0) |
norm_lrefim_comp_gain_ratio |
Test Image Mask Options
|
Mask Method |
The methodology for masking out the light source in the image(s). The default is None. Note: based on the option selected, additional inputs may be required. |
mask_method |
Test Image – Image Processing + Circle (Radius) Mask Options
The following options apply if the masking method is Image Processing + Circle (Radius). Note the Image Processing mask option also applies.
|
Radius Type |
The method for specifying the radius |
mask_2pcr_radius_type
|
|
|
Mask Radius |
The radius in pixels for the mask. The default is 10 (this is an arbitrary number and should be updated for each system under test). Note: This is only used if the Radius Type is User-Specified. |
Number (greater than 0) |
mask_options_radius |
|
Camera Pixel Pitch
|
The pixel pitch of the camera in μm.
Note: This is only used if the Radius Type is Focal Length Ratio.
|
Number |
mask_2pcr_radius_dut_pp
|
|
Camera Focal Length
|
The focal length of the camera in mm.
Note: This is only used if the Radius Type is Focal Length Ratio.
|
Number |
mask_2pcr_radius_dut_fl
|
|
Source Focal Length
|
The focal length of the light source in mm.
Note: This is only used if the Radius Type is Focal Length Ratio.
|
Number |
mask_2pcr_radius_col_fl
|
|
Source Diameter
|
The diameter of the light source pinhole in mm.
Note: This is only used if the Radius Type is Focal Length Ratio.
|
Number |
mask_2pcr_radius_col_dia
|
Test Image – Image Processing Mask Options
The following options apply if the masking method is Image Processing + Circle (Radius) or Image Processing.
|
Level Threshold Type |
The type of threshold used for localizing the light source in the image. |
Level Threshold Type Enumeration |
mask_improc_level_thresh_type |
|
Level Threshold (Value) |
The threshold above which is considered the image of the light source, in units of digital number (DN). |
Number (greater than or equal to 0) |
mask_improc_level_threshold |
|
Level Threshold (Percent) |
The threshold above which is considered the image of the light source, as a percentage of the maximum image value. |
Number (between 0 and 100) |
mask_improc_level_threshold_pct |
|
Minimum Source Level |
The minimum image value (digital number) that can be considered a direct image of the light source. |
Number (greater than or equal to 0) |
mask_improc_minimum_source_level |
|
Image Close Radius |
The radius of an image close morphology step. This helps to remove holes in the mask. Set to 0 to skip this step. This setting can only be set in the INI. |
Number (greater than 0) |
mask_improc_image_close_radius |
|
Multiple CC Strategy |
The strategy for how to deal with multiple connected components when computing the mask. This setting can only be set in the INI. |
mask_improc_multiple_cc_strategy |
|
|
Mask Area Threshold |
The minimum number of pixels that the direct image of the light source should be (minimum area in pixels for the mask). |
Number (greater than 0) |
mask_improc_mask_area_threshold |
Reference Image Source Detection Options
|
Detection Method |
The methodology for detecting the light source in the reference image(s) |
refmask_method |
Reference Image – Image Processing + Circle (Radius) Options
The following options apply if the detection method is Image Processing + Circle (Radius). Note that the Image Processing detection option also applies.
|
Radius Type |
The method for specifying the radius |
refmask_2pcr_radius_type
|
|
|
Mask Radius |
The radius in pixels for the mask. The default is 10 (this is an arbitrary number and should be updated for each system under test). Note: This is only used if the Radius Type is User-Specified. |
Number (greater than 0) |
refmask_options_radius |
|
Camera Pixel Pitch
|
The pixel pitch of the camera in μm.
Note: This is only used if the Radius Type is Focal Length Ratio.
|
Number |
refmask_2pcr_radius_dut_pp
|
|
Camera Focal Length
|
The focal length of the camera in mm.
Note: This is only used if the Radius Type is Focal Length Ratio.
|
Number |
refmask_2pcr_radius_dut_fl
|
|
Source Focal Length
|
The focal length of the light source in mm.
Note: This is only used if the Radius Type is Focal Length Ratio.
|
Number |
refmask_2pcr_radius_col_fl
|
|
Source Diameter
|
The diameter of the light source pinhole in mm.
Note: This is only used if the Radius Type is Focal Length Ratio.
|
Number |
refmask_2pcr_radius_col_dia
|
Reference Image – Image Processing Source Detection Options
The following options apply if the detection method is Image Processing + Circle (Radius) or Image Processing.
|
Level Threshold Type |
The type of threshold used for localizing the light source in the image. |
Level Threshold Type Enumeration |
refmask_improc_level_thresh_type |
|
Level Threshold (Value) |
The threshold above which is considered the image of the light source, in units of digital number (DN). |
Number (greater than or equal to 0) |
refmask_improc_level_threshold |
|
Level Threshold (Percent) |
The threshold above which is considered the image of the light source, as a percentage of the maximum image value. |
Number (between 0 and 100) |
refmask_improc_level_threshold_pct |
|
Minimum Source Level |
The minimum image value (digital number) that can be considered a direct image of the light source. This setting can only be set in the INI. |
Double (greater than or equal to 0) |
refmask_improc_minimum_source_level |
|
Image Close Radius |
The radius of an image close morphology step. This helps to remove holes in the detection. Set to 0 to skip this step. This setting can only be set in the INI. |
Number (greater than 0) |
refmask_improc_image_close_radius |
|
Multiple CC Strategy |
The strategy for how to deal with multiple connected components when computing the mask. This setting can only be set in the INI. |
refmask_improc_multiple_cc_strategy |
|
|
Mask Area Threshold |
The minimum number of pixels that the direct image of the light source should be (minimum area in pixels for the mask). This setting can only be set in the INI. |
Number (greater than 0) |
refmask_improc_mask_area_threshold |
Metadata Settings
The following options provide an alternative to the stray light configuration file for defining capture metadata. The alternate approach uses regular expression to parse the image filename and extract metadata that would otherwise come from the config file. If enabled, the regular-expression-derived metadata will have precedence over metadata from a configuration file.
|
Filename Regular Expression Method |
The regular expression method to apply to the filename. | Filename Regular Expression Enumeration |
file_regex_method |
| Filename Regular Expression | A MATLAB regular expression to apply to a filename and extract metadata. The regular expression must contain one or more named capture groups: ‘field’, ‘azimuth’, and ‘comment’. | String | file_regex |
| Decimal Point | A character representing the decimal place. This will replaced by a period before converting from string to number. | String | decimal_place |
Example Numeric Regular Expressions
The following are example regular expressions for matching numbers. Note that named capture groups are required to associate the extracted string with a particular field.
| Regular Expression |
Description |
\d+ or [0-9]+ |
Matches Positive Integers |
-?\d+ or -?[0-9]+ |
Matches Positive or Negative Integers |
[+-]?\d+(?:\.\d+)? |
Matches decimal numbers with at least one digit to the left of the decimal (e.g., will not match .1) |
[+-]?\d+(?:\.\d+)?(?:[Ee][+-]?\d+)? |
Matches decimal numbers with at least one digit to the left of the decimal including those using “E” scientific notation (e.g, will not match .2E-7) |
Example Settings
The following are example settings and what values will be extracted from the filename.
| Sample Filenames |
Regular Expression: fa(?<field>-?\d+(?:\.\d*)?) Decimal: . |
Regular Expression: field(?<field>-?\d+)_azimuth(?<azimuth>-?\d+) Decimal: . |
Regular Expression: (?<comment>[A-Za-z0-9 ]+)\/az(?<azimuth>-?\d+(?:p\d*)?)_fa(?<field>-?\d+(?:p\d*)?) Decimal: p |
| C://path/to/az0.2_fa-4.6.png |
|
|
|
| \path\to\camera123\field20_azimuth32.tiff |
|
|
|
| C://path/to/camera123/az0p2_fa-4p6.png |
|
|
|
Regular Expression Notes:
- Generic
- Having a consistent filename format will help make a reusable regular expression
- AI utilities may help construct a regular expression
- Testing the regular expression with utilities such as https://regex101.com is recommended
- For metadata extraction
- With the current architecture, the entire regex must match to extract any metadata (there is no partial extraction)
Other Calculation Settings
|
Crop LRTB |
The number of pixels to crop off the left, right, top, and bottom of the image. |
Number (list of four values greater than or equal to 0) |
crop_lrtb |
|
Percentile Ranks |
The percentile ranks [0-100] (e.g., 95 = 95th percentile) to calculate. |
Number (list of values greater than 0, less than 100) |
pctl_ranks100 |
|
Level Count Thresholds |
The thresholds of stray light level for producing results that show the number of pixels worse than said threshold. |
Number (list of values) |
level_count_thresh |
|
Level Count Calculation |
The calculation (number of pixels, % of pixels in the image) to use for the level count results and plots. |
count_type |
Output Settings
|
Save In Image Folder |
Enable to save the result(s) in the same directory as the image file. If a config file is used this will be the directory the config file is in, otherwise, the directory of the first image will be used. |
Boolean |
save_in_image_folder |
|
Save Subfolder |
The sub-folder of the image folder to save results in. If empty, this will be the same folder as the image. Note: this is only used when save in image folder is enabled. Note: inclusion of the following characters may result in failure to save .fits output files (metric images and masks): “(*:<>?[| |
String |
save_subfolder
|
|
Output Directory |
The path to the save results to. Note: this is only used when save in image folder is disabled. Note: inclusion of the following characters may result in failure to save .fits output files (metric images and masks): “(*:<>?[| |
String |
custom_save_folder
|
Result Files
|
Save Summary Results Files |
The results files to save. |
result_files |
|
|
Save Metric Image Files |
Enable to save out a FITS file containing the metric image data for each image. |
Boolean |
save_metric_image |
|
Save Mask Files |
Enable to save out a FITS file containing the binary mask of the source for each image. |
Boolean |
save_mask |
|
Mask Prefix |
A string to be prepended to the mask file(s). This setting can only be set in the INI. |
String |
mask_prefix |
|
Mask Postfix |
A string to be appended to the mask file(s). This setting can only be set in the INI. |
String |
mask_postfix |
|
Metric Image Prefix |
A string to be prepended to the metric image file(s). This setting can only be set in the INI. |
String |
metric_image_prefix |
|
Metric Image Postfix |
A string to be appended to the metric image file(s) This setting can only be set in the INI. |
String |
metric_image_postfix |
Level Plot
Note: level plots require two or more test images.
|
Save/Display |
How should level summary plot(s) be created? Choose one or more options. At least one is required to produce this plot. |
level_plot_options_mode_options |
|
|
Image Format(s) |
The image formats to save the plot as. Choose one or more options. At least one is required to produce this plot. |
level_plot_options_mode_save_types |
|
|
Groups |
How to group the data within a plot. Choose one or more options. At least one is required to produce this plot. |
level_plot_channel_grouping |
|
|
Y Data |
The data to plot on level summary plot(s). Choose one or more options. At least one is required to produce this plot. |
level_plot_include_named_data |
|
|
Include Percentiles |
Enable to include percentiles on the level summary plot(s). |
Boolean |
level_plot_include_pctls |
|
Y-Axis Scale |
The scaling of the y-axis of the plot. |
level_plot_y_axis_scale |
Count plot
|
Save/Display |
How should level summary plot(s) be created? Choose one or more options. At least one is required to produce this plot. |
count_plot_save_display |
|
|
Channel Grouping |
How to group the data within a plot. Choose one or more options. At least one is required to produce this plot. |
count_plot_channel_grouping |
|
|
Y Data |
The data to plot on count summary plot(s). Choose one or more options. At least one is required to produce this plot. |
count_plot_include_named_data |
|
|
Include Level Counts |
Enable to include level counts on the count summary plot(s), corresponding to the value(s) entered for the Level Count Threshold option. |
Boolean |
count_plot_include_level_counts |
|
Y-Axis Scale |
The scaling of the y-axis of the plot. |
count_plot_options_y_axis_scale |
Summary Videos
Colormapped Metric Video
|
Video Formats |
The formats to save the metric image video as. Note: MP4 is not available on Linux. |
metric_video_video_formats |
|
|
Image Formats: |
The image formats to save each frame of the metric image video as. |
metric_video_image_formats |
|
|
Video Frame Rate |
The framerate in frames per second for the metric video. |
Number (greater than 0, less than 40) |
metric_video_frame_rate |
|
Colormapped Image Transform |
How to scale the data before making the summary metric plot(s). Note this only applies if the Data Transform is linear. |
metric_video_linear_output_scale |
Metric Image Histogram
|
Video Formats |
The formats to save the histogram image video as. Note: MP4 is not available on Linux. |
hist_video_video_formats |
|
|
Image Formats |
The image formats to save each frame of the histogram video as. |
hist_video_image_formats |
|
|
Video Frame Rate |
The framerate in frames per second for the histogram video. |
Number (greater than 0, less than 40) |
hist_video_frame_rate |
| Y-Max Type | How to scale the maximum of the y-axis of histograms. | Histogram Y-Max Enumeration |
hist_video_ymax_type
|
| Y-Max Value | The user-provided maximum value for the y-axis of histograms. A first-order value for this value is the number of pixels in the image. | Integer (greater than 0) |
hist_video_ymax_value
|
Miscellaneous
|
Frame-to-frame Scaling |
How to scale the frames of the video relative to each other. |
frame_scaling |
|
|
Video Output Scale |
How to scale the data before making the video(s). |
video_output_scale |
Enumerations
Channel Selection Enumerations
Channel Presets Enumeration
Description
The channels to analyze.
Members
| Name | Description | Value |
| Automatic |
Automatically choose which channels to analyze based on the image data. If a one channel image provided, it will be analyzed as Monochrome, otherwise Each Channel will be used. Notes:
|
0 |
| Each Channel |
Analyze each channel. Notes:
|
1 |
| RGB |
Analyze a three-channel image as Red, Green, and Blue. Notes:
|
2 |
| Monochrome |
Analyze a one-channel image as monochrome. Notes:
|
3 |
| Statistics |
Analyze the statistics (mean, meadian) of all provided channels. Notes:
|
4 |
| Luminance |
Analyze the luminance channel computed from a three-channel image. Notes:
|
5 |
| RGB + Luminance |
Analyze the Red, Green, and Blue plus the computed luminance channels. Notes:
|
6 |
Luminance Channel Enumeration
Description
The standard to use for computing a luminance channel.
Members
| Name | Description | Value |
| IEC 61966-2-1 |
Use IEC 61966-2-1 weights (0.2126, 0.7152, 0.0722) to compute a luminance channel. |
1 |
| ITU-R BT.601-7 |
Use ITU-R BT.601-7 weights (0.299, 0.587, 0.114) to compute a luminance channel. |
2 |
| ITU-R BT.709-6 |
Use ITU-R BT.709-6 weights (0.2126, 0.7152, 0.0722) to compute a luminance channel. |
3 |
| ITU-R BT.2020-2 |
Use ITU-R BT.2020 (0.2627, 0.6780, 0.0593) weights to compute a luminance channel. |
4 |
| MATLAB |
Uses MATLAB’s rgb2gray to compute a luminance channel. |
6 |
RGB Order
Description
The ordering of the red, green, and blue data within an image
Members
| Name | Description | Value |
| RGB |
The image data is ordered red, green, blue.
|
0 |
| BGR |
The image data is ordered blue, green, red.
|
1 |
Channel Statistics
Description
The standard to use for computing a luminance channel.
Members
| Name | Description | Value |
| Mean |
Analyze the mean of the provided channels. |
0 |
| Median |
Analyze the median of the provided channels. |
1 |
Single Choice Enumerations
For the following enumerations, choose one of the provided options.
Axis Scaling Enumeration
Description
How to scale the axis of a plot.
Members
| Name | Description | Value |
| Linear |
The axis uses a linear scale. |
0 |
| Log |
The axis uses a log scale. |
1 |
Calculation Type Enumeration
Description
The type of stray light calculation to perform.
Members
| Name | Description | Value |
| Transmission |
The calculation is the image divided by the normalization factor. |
0 |
| Attenuation |
The calculation is the normalization factor divided by the image. Note: 0 is a valid digital number for image data. If choosing attenuation, any image with 0’s in it will get infinity for the calculated stray light. Summary statistics (e.g., mean, max) of data containing infinity become meaningless. Therefore it is recommended to enable Crop To One if this option is chosen. |
1 |
Data Transform Enumeration
Description
How to transform data.
Members
| Name | Description | Value |
| Linear |
Apply no transform to the data \(y=x\). |
0 |
| Log 10 |
Apply a base-10 logarithm to the data \(y=log_{10}(x)\). |
1 |
| dB Power |
Convert the data to power decibels \(y=10\cdot log_{10}(x)\). |
2 |
| dB Voltage |
Convert the data to voltage decibels \(y=20\cdot log_{10}(x)\). |
3 |
| Log 2 |
Apply a base-2 logarithm to the data \(y=log_{2}(x)\). |
4 |
| Natural Log |
Apply a natural logarithm to the data \(y=ln(x)\). |
5 |
Notes
Note: 0 is a valid digital number for image data. The log (any base) of zero is undefined, although computed to negative infinity. Summary statistics (e.g., mean, max) of data containing infinity become meaningless. Therefore it is recommended to enable Crop To One if any of the logarithmic data transform options is chosen.
Filename Regular Expression Enum
Description
How to transform data.
Members
| Name | Description | Value |
| None |
Do not perform a regular expression search. The only way to provide metadata is via a stray light config file. |
0 |
| Regular Expression |
Use a single regular expression extract metadata from the filename. If enabled, this will overwrite any metadata provided in a stray light config file. |
1 |
Histogram Y-Max Type Enumeration
Description
How to set the maximum y-value in a histogram plot
Members
| Name | Description | Value |
|
Automatic
|
Automatically scale for each frame. |
1 |
|
User-defined
|
Use a constant, user-defined maximum value. |
2 |
Image Processing Masking Level Type Enumeration
Description
The type of threshold used for localizing the light source in the image.
Members
| Name | Description | Value |
| Value |
The threshold in digital numbers. |
0 |
| Percentage of Max |
The threshold is a percentage of the maximum value [0-100]. |
1 |
| Otsu’s Method |
Use Otsu’s method to automatically determine a threshold. |
2 |
Image Processing Masking Multiple Connected Component Enumeration
Description
The strategy for dealing with multiple connected components when computing the mask.
Members
| Name | Description | Value |
| Don’t Mask |
If multiple CCs are found, assume the source is not in the image. |
1 |
| Pick Biggest |
Pick the largest of the connected components. |
2 |
| Pick Smallest |
Pick the smallest of the connected components. |
3 |
Level Count Calculation Enumeration
Description
The calculation to make for count-based summary metrics.
Members
| Name | Description | Value |
| Number of Pixels |
The results will use the number of pixels in the image that match the criteria |
1 |
| Percent of Pixels |
The results will use the percentage of pixels in the image that match the criteria. |
2 |
Light Measurement Type Enumeration
Description
The type (radiometric/photometric) of light level measurement that was made.
Members
| Name | Description | Value |
| Radiometric |
Radiometric light level measurements are made (e.g., radiance, irradiance). |
0 |
| Photometric |
Photometric light level measurements are made (e.g., luminance, illuminance). |
1 |
Mask Method Enumeration
Description
The methodology for masking out the light source in the image(s).
Members
| Name | Description | Value |
| None |
Don’t mask the source. Note: This is not available for masking reference images. |
0 |
| Image Processing |
Use image processing to mask the source. |
10 |
| Image Processing + Circle (Radius) | Find the center via the first step of Image Processing masking, and then use a circle to mask. The light source is first localized in the image via image processing-based methods. Then, a circle of a specified radius is placed at the center of the localized region and is used as the mask for the image | 13 |
Mask Radius Enumeration
Description
The methodology for determining the radius of a mask.
Members
| Name | Description | Value |
| User-Specified |
Specify a radius in pixels |
0 |
| Focal Length Ratio |
Specify the mask radius by using a ratio of focal lengths. From IEEE Std. 2020. |
1 |
Memory Mode Enumeration
Description
How to prioritize memory or disk i/o during the stray light analysis.
Members
| Name | Description | Value |
| High Memory |
Keep everything in memory during the analysis. Note: This is the pre-24.2 behavior. |
1 |
| Low Memory |
Keep limited information in memory during the analysis. Metric image outputs will be read back in as needed during the analysis. Note: If saving color-mapped metric images and/or histograms, save metric images must be enabled. Note: This is not available for trials. |
2 |
Normalization Aggregation Enumeration
Description
The methodology for aggregating the masked pixels into a normalization factor.
Members
| Name | Description | Value |
| Mean |
Use the mean inside the masked pixels as the base normalization factor. |
0 |
| Median |
Use the median inside the masked pixels as the base normalization factor. |
1 |
| Total |
Use the total (sum) inside the masked pixels as the base normalization factor. |
2 |
Normalization Method Enumeration
Description
The type of normalization to perform.
Members
| Name | Description | Value |
| None |
Perform no normalization. Results will be in digital numbers. |
0 |
| Level | Normalize with a user-provided source level in units of digital number (DN). Using this option requires the Level normalization settings. | 1 |
| Direct Reference Image | Normalize by the level of the direct image of the source from a reference image. This normalization method corresponds to the Point Source Rejection Ratio (PSRR) or Extended Source Rejection Ratio (ESRR). Using this option requires the Direct Reference Image normalization settings. | 3 |
| Lambertian Reference Image | Normalize by the level of an image of the source as viewed through a Lambertian diffuser. This normalization method corresponds to the Flare Attenuation method in IEEE-P2020 Pre-Release. Using this option requires the Lambertian Reference Image Normalization settings. | 4 |
Neutral Density Measurement Enumeration
Description
The type of neutral density measurement used for the reference image capture.
Members
| Name | Description | Value |
| None |
No ND filter is used for the reference image. |
0 |
| Density |
ND filter(s) are used. The value is the total density of filters. |
1 |
| Transmission | ND filter(s) are used. The value is the total transmission as a percentage [0-100] of the filters. | 2 |
Saturation Calculation Enumeration
Description
The saturation calculation method.
Members
| Name | Description | Value |
| Container Max | Use the maximum value of the container. | 0 |
| Image Max | Use the maximum value of the image. | 1 |
| Image Max (Power of Two) | Use the maximum value of the image, rounded up to 2N-1. | 2 |
| Image Max (Even Power of Two) | Use the maximum value of the image, rounded up to 22N-1. | 3 |
| Specify Bit Depth | Specify the saturation level in bits. | 4 |
| Specify Value | Specify the saturation level in digital numbers. | 5 |
Video Frame Scaling Enumeration
Description
How to scale the frames of a video relative to each other.
Members
| Name | Description | Value |
| Global |
All frames have the same scaling. |
0 |
| Per-Subset |
All frames of the same subset (channel) have the same scaling. |
1 |
| Per-Image |
Each frame of the video will have its own scale. |
2 |
Multiple Choice Enumerations
For the following enumerations, choose any of the provided options. The value in the INI is the sum of desired options.
Results File Type Enumeration
Description
The type(s) of summary results file to save.
Members
| Name | Description | Value |
| JSON |
Save a JSON-formatted results file. |
1 |
| CSV |
Save a CSV-formatted results file. |
2 |
| XML |
Save an XML-formatted results file. |
3 |
| HDF5 |
Save an HDF5-formatted results file. |
4 |
Plot Creation Enumeration
Description
Select how to create (display, save) plot(s).
Members
| Name | Description | Value |
| Save |
Save plot(s) to disk. |
1 |
| Display |
Display plot(s) to the screen. |
2 |
Plot Save Type Enumeration
Description
The image formats to save the plot as.
Members
| Name | Description | Value |
|
JPEG 24-bit (.jpg) |
1 | |
|
PNG 24-bit (.png) |
2 | |
|
TIFF 24-bit [compressed] (.tif) |
|
4 |
|
TIFF 24-bit [not compressed] (.tif) |
|
8 |
|
BMP 8-bit [256 color, uses a fixed colormap] (.bmp) |
This will be deprecated in a future release. |
16 |
|
HDF 24-bit (.hdf) |
This will be deprecated in a future release. |
32 |
|
PBM 1-bit (.pbm) |
This will be deprecated in a future release. |
64 |
|
PCX 24-bit color [three 8-bit planes] (.pcx) |
This will be deprecated in a future release. |
128 |
|
PGM (.pgm) |
This will be deprecated in a future release. |
256 |
|
PPM (.ppm) |
This will be deprecated in a future release. |
512 |
|
Full page Portable Document Format [PDF] color (.pdf) |
|
1024 |
|
Encapsulated PostScript [EPS] Level 2 color (.eps) |
|
2048 |
|
SVG [scalable vector graphics] (.svg) |
|
4096 |
|
Full-page PostScript [PS] Level 2 color (.ps) |
|
8192 |
| MATLAB Figure (.fig) |
|
16384 |
Deprecation Warning
Some options will be deprecated in a future Imatest release.
Plot Grouping Enumeration
Description
How to group the data within a plot. At least one is required to produce this plot.
Members
| Name | Description | Value |
|
All |
All channels will be in the same plot. | 1 |
| By Channel | A separate plot will be made for each channel. | 2 |
Level Plot Data Enumeration
Description
The data to plot on level summary plot(s).
Members
| Name | Description | Value |
|
Minimum |
1 | |
|
Minimum (Non-0) |
Minimum of the non-0 data in the original image. | 2 |
|
Maximum |
|
4 |
|
Mean |
|
8 |
|
Median |
|
16 |
|
RMS |
Root Mean Square |
32 |
|
Std. Dev. |
Standard Deviation |
64 |
Count Plot Data Enumeration
Description
The data to plot on count summary plot(s).
Members
| Name | Description | Value |
|
Total Count |
The number/count of pixels in the region of interest (note: currently, only the total number of pixels in the image is available). | 1 |
|
Source Count |
The number/count of pixels in the masked region (the light source object). | 2 |
|
Saturation Count |
The number/count of pixels at or above the calculated saturation level. | 4 |
Video Save Type Enumeration
Description
The formats to save a video as.
Members
| Name | Description | Value |
|
MP4 |
Note: Not available on Linux | 1 |
|
AVI |
2 |
|
|
GIF |
4 |
Image Frame Save Formats
Description
The image formats to save each frame of a video as.
Members
| Name | Description | Value |
|
PNG |
1 | |
|
JPEG |
2 | |
|
TIFF |
4 |
History
24.2 Changes
INI Syntax Updates
- Arrays are now comma-separated and contained within square brackets
- crop_lrtb
- pctl_ranks100
- level_count_thresh
- plot_save_types
- Strings are now contained within double quotes
- norm_refim_filename
- norm_lrefim_filename
INI Key Updates
The following INI keys have been updated
| Old INI Key | New INI Key(s) |
| channels | channel_type |
| count_per_plot_scaling | count_plot_per_plot_scaling |
| count_plot_options_groups | count_plot_channel_grouping |
| count_plot_options_include_level_counts | count_plot_include_level_counts |
| count_plot_options_mode_options | count_plot_save_display |
| count_plot_options_mode_save_types | plot_save_type |
| count_plot_options_y_data | count_plot_include_named_data |
| count_plot_yaxisscale | count_plot_y_axis_scale |
| hist_video_opts_frame_rate | hist_video_frame_rate |
| hist_video_opts_image_formats | hist_video_image_formats |
| hist_video_opts_video_formats | hist_video_video_formats |
| level_plot_options_groups | level_plot_channel_grouping |
| level_plot_options_include_pctls | level_plot_include_pctls |
| level_plot_options_mode_options | level_save_display |
| level_plot_options_mode_save_types | plot_save_type |
| level_plot_options_y_axis_scale | level_plot_y_axis_scale |
| level_plot_options_y_data | level_plot_include_named_data |
| lum_type | channel_lum_type |
| metric_video_opts_frame_rate | metric_video_frame_rate |
| metric_video_opts_image_formats | metric_video_image_formats |
| metric_video_opts_video_formats | metric_video_video_formats |
| output_dir | save_in_image_folder, custom_save_folder, save_subfolder |
| pctl_ranks100 | percentile_ranks100 |
| plot_output_scale | metric_video_linear_output_scale |
| result_files | result_save_types |
| rgb_order | channel_rgb_order |
The following INI keys have been deprecated
- mask_postfix
- mask_prefix
- metric_image_postfix
- metric_image_prefix
- metric_video_opts_basename
- hist_video_opts_basename
- video_prefix
- video_postfix
- video_output_scale
Plot Save Format Updates
| Save Format | Old INI Value | New INI Value |
| <None> | 0 | [] |
| JPEG | 1 | 1 |
| PNG | 2 | 2 |
| TIFF (uncompressed) | 4 | 3 |
| TIFF (compressed | 8 | 4 |
| BMP | 16 | Deprecated |
| HDF | 32 | Deprecated |
| PBM | 64 | Deprecated |
| PCX | 128 | Deprecated |
| PGM | 256 | Deprecated |
| PPM | 512 | Deprecated |
| 1024 | 6 | |
| EPS | 2048 | 7 |
| SVG | 4096 | 11 |
| PS | 8192 | Deprecated |
| MATLAB FIG | 16384 | 5 |
Python INI Migrator
To help with migrating the stray light portion of your INI to 24.2, a python migration utility is provided with Imatest 24.2.
The python code for imatest_straylight_24_2_ini_migrator comes already installed as a Python package in the Python interpreter that is included in the Imatest Master or IT installation (see <Imatest Master/IT root>/bin/python39). The relevant Python function has the following interface
def migrate_ini(filename: str) -> None
and can be invoked in this interpreter with
from imatest_straylight_24_2_ini_migrator.imatest_straylight_24_2_ini_migrator import migrate_ini
migrate_ini("/some/folder/imatest-v2.ini")
In addition to the Python code, there is also a standalone executable (located at <Imatest Master/IT root>/bin/python39/bin for macOS and Linux and <Imatest Master/IT root>/bin/python39/Scriptsfor Windows) named imatest-straylight-24-2-ini-migrator. The application’s interface is as follows:
$ imatest-straylight-24-2-ini-migrator.exe --help usage: imatest-straylight-24-2-ini-migrator [-h] filename Migrate the stray light section of an Imatest INI file from 24.1 to 24.2. positional arguments: filename The path to the INI file. The default INI location is `C:\Users\Ty\AppData\Roaming\Imatest\imatest-v2.ini`. optional arguments: -h, --help show this help message and exit
, which can be invoked with a call such as
imatest-straylight-24-2-ini-migrator "/some/folder/imatest-v2.ini"