The ISO12233:2014 standard defines three test charts. The new Imatest eSFR ISO module performs a highly automated analysis of the new low-contrast (4:1) Edge SFR image and is provided in Imatest Master and Image Sensor 4.0.

ISO 12233: 2014 test chart
CIPA resolution (wedge) test chart	Hyperbolic wedge: 4 vertical directions, 4 horizontal directions and 2 diagonal (45 degrees) directions. The ImatestWedge module with manual area detection supports vertical and horizontal wedges, but does not support diagonal wedges.
Low contrast bevel edge SFR (E-SFR) test card	Contains 9 oblique squares for oblique edge measurement. 4:1 contrast ratio: much lower than the old ISO 12233:2000 chart (>40:1), which can avoid clipping and non-linear problems. For highly automated measurements (including squares, color blocks and wedges near the corners), we recommend that you use the Imatest eSFR ISO test card. These test cards are fully compliant with ISO 12233:2014.
SFR test chart based on sine change	Siemens Star Chart Supported by the Imatest Dot Pattern module. This module supports automatic star map detection and analysis, but only one star map can be detected at a time.
Old ISO-12233 chart	2000 version The old high-contrast ISO 12233 chart shown on the right is referenced in the ISO 12233:2000 standard, but is no longer part of the standard. If the test result needs to be compared with the work before 2014, it can be used as a reference.

Imatest ISO 12233: 2014 Edge SFR chart

There are three types of Imatest eSFR ISO test charts: standard, enhanced and extended. All of these are in line with the standards of the chart shown in the ISO 12233:2014 document.

Standard eSFR ISO chart: 3:2 aspect ratio, no additional functions

Enhanced eSFR ISO test chart: 3:2 aspect ratio, 6 sides plus square,
16 add color blocks, a few add wedge patterns.

Extended eSFR ISO test chart: 16:9 aspect ratio for HD TV and movies (for SLR cameras),
Six squares, 16 additional color blocks, and several additional wedge patterns have been added to the side.

The sharpness comes from the edge of the slanted rectangular boundary. eSFR ISO can handle various camera aspect ratios; when shooting a chart, the viewfinder can extend beyond the left and right sides of the test card or be inside it.

ImatestImatest's standard ESFR test card is very close to the test card shown in the ISO 12233:2014 standard document. On this basis, there are some subtle differences.

1. There are four registered (trusted) marks instead of three. Another black circle above the registration mark in the lower left corner is used to detect the orientation. This change is because the projection transformation used for automatic area detection requires four points. "Asymmetric features of automatic target detection", these features should be placed in the effective area of 4:3 aspect ratio range, but can be conveniently placed according to the use case. "
2. The focus assist patterns in the center of the square are different from the patterns shown in the ISO standard documents (not described in the standard): they are square (this allows more space for the oblique edge area for measuring sharpness), and they Designed to minimize interference with automatic area detection. They have no influence on the measurement results.
3. Use 20 patch OECF grayscale patterns. Said: "The test chart also includes the gray-scale patch used to determine the OECF, while the example chart in Figure C1 uses 16 OECF test gray-scales; it can also replace the 20 gray-scales described in ISO 14524. The enhanced and expanded chart will be Features added to the chart in areas not specified by the ISO standard (but not violated), which are valuable to most users.

Video introduction: eSFR ISO test card structure

eSFR ISO chart type
Chart type	Feature	Detail
Standard	The closest to the chart in the standard file. No added features.	The sharpness cannot be measured at or near the edges of the image. Use only when needed. It is recommended to use enhanced or extended charts for most purposes.
Enhanced	3:2 aspect ratio. Add 6 squares on the side; add a few hyperbolic wedges; add 16 color blocks to the inkjet and 8x10 inch LVT charts produced by Imatest.	Most suitable for 4:3 or 3:2 aspect ratio (camera phones, compact cameras, digital SLR cameras) Includes several hyperbolic wedges with similar ISO (CIPA) visual resolution test chart, supported by Imatest (manual ROI detection) wedge module
Extended	16:9 aspect ratio. Same function as enhanced image.	Suitable for 3:2 or 16:9 aspect ratio (DSLR, HDTV and cinema formats)

eSFR ISO chart printing options
	Options	Detail
Chart aspect ratio	3:2 (standard and enhanced) or 16:9 (extended)	The 3:2 chart (standard and enhanced) is very suitable for SLR cameras (3:2 aspect ratio) and small digital cameras and camera phones (4:3 aspect ratio). The 16:9 (extended) chart is very suitable for HDTV (16:9 aspect ratio) and SLR cameras (3:2 aspect ratio).
Contrast	Only 4:1	The 4:1 contrast ratio is specified in the new ISO 12233:2014 standard.
Grayscale step chart	Include (below the center)	Contains a 20-patch ISO 14524 circular grayscale pattern.
Color chart	16 patches	Included in all inkjet printing enhanced and extended inkjet charts (all sizes) and LVT film (up to 8x10 inches) produced by Imatest. (Not available for reflective photos, not available yet.)
Predistortion	Undistorted (standard), two standard levels of predistortion, custom predistortion	Pincushion pre-distortion can be used for fisheye (strong barrel distortion) lenses. Only suitable for matt surfaces. Please refer to the pre-distortion SFRplus test card for fisheye lenses.
Extra wedges	Standard (4 wedge pairs), Extra wedges	There are 4 pairs of low-frequency and high-frequency wedges in the standard enhanced and expanded images. The version with additional wedges has at least 12 additional high-frequency wedges: 4 near the center and 8 near the corners.
Media (surface)	Matte inkjet Semigloss inkjet Photographic reflection LVT film: color up to 8x10 inches; B&W up to 12x20 inches	Semigloss inkjet printers are slightly sharper and more accurate than grayscale inkjet printing in dark tones (printing density> 1.5), but are more susceptible to glare (specular reflection), especially wide-angle lenses. A matte surface is recommended for wide-angle lenses. Film (reflection and LVT film transmission) is much finer than inkjet: the same size chart can analyze a camera with a much higher resolution.

Imatest eSFR ISO module

The new Imatest eSFR ISO module uses the new version of ISO 12233: 2014 E-SFR (Edge SFR) test chart. Image quality factors include:

· Sharpness: Expressed as spatial frequency response (SFR), also known as modulation transfer function (MTF).
Noise: Measured from the gray scale near the center of the chart, including all types of noise calculated by Multicharts and Multitest (standard pixel noise, chrominance noise, scene reference noise, sensor (raw) noise and ISO-15739 visual noise). SNR (signal to noise ratio) can also be expressed in dB or dB.
· Lateral chromatic aberration
· Distortion (has less detail than the distortion module). SFRplus distortion and field of view measurement details.
· Tonal response (less details compared with Stepchart, no noise statistics).
· When used with an eSFR ISO chart with optional color patterns, the color accuracy is located above the center of the test card.
· When inputting incident light, ISO sensitivity (based on saturation and standard output sensitivity).
· The starting point of aliasing and moiré measured from the four pairs of wedges in the enhancement and expansion chart has the same spatial frequency range as the separate ISO 12233:2014 wedge chart. The numbers and results are the same as the Wedge module.

All chart functions-slanted edges, gray patches, color blocks and wedges will be positioned automatically.

eSFR ISO has two modes:

· Interactive/setup mode (by pressing Rescharts or eSFR ISO settings in the main window of Imatest to run), allows you to select settings and interactively check the results in detail.
· Automatic mode (press eSFR ISO Auto to run in the main window of Imatest), which can run automatically without other user input. The ROI will be set automatically according to the settings saved in the interactive/setting mode. In this way, images of different sizes and frames can be analyzed without changing the settings. The automatic mode is suitable for large batches of files and is especially useful for automatic testing, where the frame may vary from image to image.

The ISO 12233:2014 edge SFR test chart is better than the old ISO 12233:2000 test card

Note: The old ISO 12233:2000 standard and chart shown on the right are referenced in the new ISO 122433:2014 standard, but it is no longer an official part of the standard. The new standard specifies three graphs, one of which is a slope (Edge SFR or E-SFR) graph with a much lower contrast ratio (4:1; as shown in the figure on the right).

Compared with the old ISO 12233 chart:

· The new eSFR ISO chart is much less wasteful, especially in the enhanced and extended versions. Approximately 90% of the old ISO test card area is of no value to computer analysis.
· You can use enhanced and expanded charts to generate detailed results of sharpness (MTF) on the image surface. The old ISO chart cannot be realized because there are not enough edges and their position distribution is not very good.

ISO 12233: 2014 Edge SFR chart

· Automatic area detection, based on the location conditions you enter. This makes the eSFR ISO charts and modules very suitable for automated testing: with the old ISO charts, as long as the image frame changes, even if it changes slightly, the region of interest (ROI) must be carefully selected.
· 4:1 contrast edges are less likely to be cut than the edges in the old ISO chart, and the contrast ratio is specified at ≥40:1. The camera works in a more linear area, so the results are more consistent and accurate-not affected by overexposure, underexposure, incorrect gamma estimation or excessive software sharpening. The 4:1 contrast edge is also more representative of the real edge that affects the perceived image sharpness.

· eSFR ISO can measure additional image quality factors, including lateral chromatic aberration, distortion, gamma (contrast), tone response, and color accuracy (in a chart with color patterns).

· The old ISO 12233:2000 chart does not contain information that can be used to measure gamma (the average slope of the Log object vs. the log exposure curve, that is, the contrast), which is required for the image linearization calculated by the MTF. Accurate gamma measurement is particularly important for high-contrast targets. In the eSFR ISO chart, the gamma can be derived from individual squares (which have a known 4:1 contrast) or gray-level chart.

Compared with the SFRplus diagram:
· The mapping of MTF on the image surface has less details.
· Since there is no distortion bar and there are fewer distortion measurement functions, the accuracy of distortion measurement is slightly worse (especially for standard graphs).
· You can use detailed noise analysis (including all types of noise measured in Multicharts and Multitest).
· Wedge analysis (including initial aliasing and moiré) can be used. The standard chart has 4 pairs of added wedges. A version of the chart has at least 12 additional wedges (4 near the center and 8 near the corners).