PhotoAcute Users Guide

Table of contents

    Image resolution increase beyond camera capabilities
    Expansion of dynamic range
    Depth of field expansion
    Correction of chromatic aberrations
    Noise reduction without losing image details
    Correction of image geometry

First-time usage: step-by-step instruction

How to use
    Loading pictures and managing the pictures list
    Processing options
    Viewing the pictures
    Saving the results
    Recommendations on taking and processing the images

Product registration
    Trial mode limitations
    How to register

What's new in PhotoAcute version 3
    Features added in version 3
    Features to be added in the nearest future
    Features absent in version 3


Visit product website:
Contact PhotoAcute support:
© Almalence Inc. 2007-2011


PhotoAcute is a leading edge tool for enhancing the quality of digital photographs.

PhotoAcute processes sets of photographs taken in continuous mode to produce high-resolution, low-noise pictures. It increases image resolution, removes noise without losing image details, corrects image geometry and chromatic aberrations and expands the dynamic range.

Examples (on site):


^ Index :: ^ Features

Image resolution increase beyond camera capabilities

PhotoAcute produces a combined image from a sequence of continuous photographs, thus acquiring more graphic information than is available from any one photograph. Using sophisticated proprietary algorithms, it combines the individual frames to produce one large- sized and high-quality image. This kind of technique is usually called "super-resolution processing".

Unlike digital zooming and image sharpening, the photographs produced by PhotoAcute do really have higher spatial resolution.

Small, thin and far-away objects, traceries, textures and inscriptions become recognizable.

PhotoAcute super-resolution algorithms are tuned for particular camera/lens models to achieve maximum quality.

original original sharpened superresolution result superresolution result sharpened
source photograph (one of a set): camera resolution was not enough to capture the brickwork pattern strong sharpening does not reveal more details super-resolution applied to the whole set of photographs: the pattern is much more apparent, as if it was captured by a camera with higher resolution sharpening applied to the result of superresolution processing - for comparison with the sharpened original

Usage: To perform Super Resolution processing turn on the Increase Resolution option in the processing options pane.. Superresolution processing depends on a camera profile for the given camera model.

It is highly recommended to use high ISO levels (e.g. 400) for super-resolution processing. Cameras automatically use long exposures when ISO is low, and this leads to handshaking artifacts that can significantly decrease the level of detail of the picture. At the same time, the noise caused by high ISO can be efficiently reduced during super-resolution processing.

More information:
Super Resolution FAQ (on PhotoAcute site)
Measuring the increase of image resolution (on PhotoAcute site)
Read more about Super Resolution at Wikipedia

^ Index :: ^ Features

Expansion of the Dynamic Range (HDR image blending)

By using an advanced weighting technique, PhotoAcute is able to restore shadows and clipped highlights from photographs taken in exposure-bracketing mode. It produces an image that otherwise could only be taken with a camera that had much wider dynamic range.

This feature becomes especially handy for objects photographed on back-lit background (e.g. window, a light snow, direct sunlight), or scenes that have important details in the shadow.

PhotoAcute introduces advanced HDR blending techniques: a precise radiometric alignment for producing consistent HDR images of scenes with moving objects and varying illumination; and "Noise-free HDR" to get rid of the noise in shadow areas of HDR images.

highlights captured, shadows lost shadows captured, highlights lost both shadow and highlight details are visible
highlights captured, shadows lost shadows captured, highlights lost both shadow and highlight details are visible

Usage: Dynamic range expansion is turned on/off with the Blens HDR image option the corresponding checkbox in the processing options pane.

More information:
Read more about dynamic range
Precise radiometric alignment: Produce consistent HDR images of scenes with moving objects and varying illumination. (on PhotoAcute site)
Noise-free HDR: expand dynamic range and get rid of the noise (on PhotoAcute site)

^ Index :: ^ Features

Depth of field expansion (focus stacking)

Focus stacking is a digital image processing technique which combines multiple images taken at different focal distances to give a resulting image with a greater depth of field than any of the individual source images.

The classic way to extend depth of field is to take images using a narrow lens aperture. This solution has two serious disadvantages. Small apertures bring more light diffraction, degrading the image resolution and they reduce the light transmission, forcing the use of longer exposures, which leads to motion blur in the pictures. Also, even using the smallest aperture is sometimes not enough to capture the entire scene sharply.

The alternative way is to take several frames of the same scene with different focal lengths. Each of these images has its own depth of field and they can be merged together, combining focused areas of each image and producing a resulting image with cumulative depth of field.

Using this technique is essential in macro-photography and micro-photography as well as in all situations when the very near and very far objects in the scene have to be captured acutely.

Usage: Turn on the Focus stacking option in the processing options pane.

^ Index :: ^ Features

Correction of chromatic aberrations

Every lens focuses the light of different wavelengths in different positions. This causes chromatic aberration that is seen as "fringes" of color around the image. PhotoAcute corrects this aberration, minimizing the circle of confusion.
The correction is performed automatically, with no need of manual adjustments of any parameters.

source photograph color fringes resultant image
source photograph color fringes resulting photograph

Usage: Color fringing correction is turned on/off with the Fix chromatic aberrations option the corresponding checkbox in the processing options pane.

More information:
Read more about chromatic aberrations

^ Index :: ^ Features

Noise reduction without losing image details

By combining several imagess, PhotoAcute automatically reduces the noise.

The main problem of noise reduction techniques is that the more noise is reduced, the more image details are lost. This becomes extremely apparent in the low light scenes (e.g. night photos or shadowy parts of the scene).

PhotoAcute provides high noise reduction without losing the image details.

source photographs noise reduction PhotoAcute noise reduction
source photograph (one of a set) a photograph processed using the noise reduction utility (one of the leaders on the market) whole set, as processed by PhotoAcute with NO super-resolution

Usage: Noise reduction is performed automatically when stacking the images.

More information:
Read more about noise and its reduction

^ Index :: ^ Features

Correction of image geometry

PhotoAcute corrects geometric distortion caused by the camera optics. This gives photographs the right perspective and a natural look.

Usage: Geometry correction is turned on/off with the Correct geomerty option in the processing options pane. This feature requires availability of a profile for the given camera/lens combination.

First-time usage: step-by-step instruction

1. Take a sequence of photos of a scene

You can switch the camera to a continuous mode or take the photos one by one. RAW format is prefferable, especially for the super resolution.

2. Load the photos in PhotoAcute

Click the Open link in PhotoAcute or drag-n-drop the files to PhotoAcute window.

3. Set processing options and start the processing

Click the Adjust processing options link.
For the first-time usage you can simply select a preset, depending on the nature of the images. E.g., for super resolution processing select "Superresolution, tripod" or "Superresolution, handheld" preset. For processing exposure-bracketed images (dynamic range expansion) select one of "HDR" presets, and so on.
More information on processing options
Once the options are set, click the Process this group link.

4. Examine the result

Once the processing is successfully completed, PhotoAcute switches to the tiled mode, displaying one of the original images and the resulting image side by side.
When you drag one of the images (by mouse), the other one is moved correspondingly. You can drag a single image without moving the other one by pressing [Ctrl] key while dragging ([Shift] key on Mac).

5. Save the result

Select the resulting image in the list and click the Save link.

How to use

^ Index :: ^ How to Use

Loading pictures and managing the pictures list

To load pictures into PhotoAcute Studio, you can either:
• Click the Open link and select the files
• Drag-n-drop the image files from Windows Explorer / Mac Finder.

To remove an image from the list, select it and click the Close link.

Note. Previews of RAW data displayed in PhotoAcute are calculated with default parameters. Have no worries about improper white balance or absence of control over image parameters: PhotoAcute performs a RAW-in-RAW-out processing. You will be able to tweak all parameters of the final result later in your favorite RAW converter.

^ Index :: ^ How to Use

Processing options

There are three groups of processing options (see the screenshot below):
  • Operations (A in screenshot) - what processing is to be performed
  • Camera profile (B) - what camera/lens profile should be used (if needed)
  • Alignment options (C)

  • Processing Options Screenshot


    There are several presets designed for typical situations and purposes of processing. When you select a preset (D), the options are automatically adjusted. You can still adjust the options manually if needed.


    Increase resolution
    Perform superresolution processing. This feature is better used with a proper profile designed for the given camera and lens combination.

    Blend HDR Image
    Blend exposure bracketed images into a High Dynamic Range image. This operation does HDR blending only, with no tone mapping. Then the result can be used in tone mapping workflow.

    Expand Depth of Field
    Stack differently focused images into an image with all areas in focus (Focus stacking).

    Fix chromatic aberrations
    Automatic correction of chromatic aberrations caused by different focusing of the light of different wavelengths.

    Correct image geometry
    Fix geometry distortions specific for the given camera and lens (requires a camera/lens profile).

    Camera profile

    A camera/lens profile is required for superresolution and geometry correction.
    If there is no profile for your camera/lens, you can try using other profiles for superresolution. More information on cameras and lenses support can be found in PhotoAcute FAQ (on site)

    Alignment options

    Camera stability
    Regulates the maximum amount of displacement between the images. Normally, you should just choose between 'tripod' and 'handheld'.

    Spatial alignment
    Regulates the complexity of image deformation. The default '5x5 grid elastic deformation' value should work for most cases. Use higher values for lenses with extreme distortion (e.g., fisheye), for images distorted due to athmosperic disturbances, and so on. Avoid using high values for scenes with moving objects.

    Base image
    The base image for alignment. For the best results this should be an image with less blur and less clipped areas. You can select the image manually or use automatic settings: 'less blurred' for superresolution, 'best exposed' for HDR blending.

    Moving objects
    If 'No processing' is selected - the moving objects will be simply averaged.
    'Take from the base image' - the moving objects are taken from the image selected as the base image.
    'Remove or deghost' - try to remove the moving objects. The objects that cannot be removed smoothly are processed to avoid ghosting artefacts.

    Radiometric alignment
    Radiometric alignment is used to avoid artefacts caused by moving objects and varying illumination of a scene.
    Due to a varying lighting, non-linear sensor response and scene movement, two identical color values in two images can be in fact different in the scene. Color values in an image are related to image irradiance by a nonlinear function. Radiometric alignment is a process of estimating this nonlinear function.
    Read more: Precise radiometric alignment (on site)

    ^ Index :: ^ How to Use

    Viewing the pictures

    On the right pane, either the currently selected image or all the marked images(in Tiled mode) are displayed.

    A thumbnail of the currently selected image is displayed in the bottom of the PhotoAcute window. The red rectangle in the thumbnail designates the area being shown in the right pane. You can drag this rectangle to scroll the image.

    Tiled mode

    PhotoAcute provides you with an easy and effective method of comparing the result with the original images.
    In the 'Results' pane check the 'Tile' box and select the resulting image and one or more of the source images.
    Source photographs are scaled to the size of the resulting image.
    You can drag the images with the mouse. When you drag one of the images, all images move together so that you can easily compare the matching areas of the images.
    Adjust individual images by dragging them and holding the [Ctrl] key pressed ([Shift] key on Mac).
    Use the mouse wheel or scale listbox to change scale.

    Viewing RAW Images

    Previews of RAW data displayed in PhotoAcute are calculated with default parameters. Have no worries about improper white balance or absence of control over image parameters: PhotoAcute performs a RAW-in-RAW-out processing. You will be able to tweak all parameters of the final result later in your favorite RAW converter.

    ^ Index :: ^ How to Use

    Saving the results

    To save the resulting image, select it in the list and click the Save link.


    A watermark is placed in the saved images in trial mode and in case your license does not allow the kind of processing (say, processing RAW images with Lite license - you are able to process and view the result, but a watermark is placed when the result is saved).
    For the detailed description of license types and what features are available with certain license, please go to PhotoAcute Order Page.

    ^ Index :: ^ How to Use


    To open the Settings window, click the Settings link.


    Prompt Save on exit/close
    When you are closing the unsaved image or exiting the program while there are unsaved images, PhotoAcute Studio will display a confirmation window if this option is turned on.

    Confirm saving RAW images in non-RAW formats
    Display a warning when a non-RAW format is selected for saving RAW image.

    Jpeg quality
    This parameter controls the compression rate used when saving the images in JPEG format.
    The higher is the value - the lower is the compression rate.


    Scratch folder
    The Scratch folder is used for storing image data during the processing.


    Use RAW profiles for 16/32 bit images
    Superresolution profiles differ for JPEG and RAW images. For non-RAW 16/32 bit images produced with no JPEG-compression and in-camera processing (say, for a TIFF produces from RAW) it is recommended to use RAW profiles.

    Crop unmatched edges
    Crop the resulting images so that they should not contain the edge areas which do not covered by some of the source images.

    Allow tone mapping
    Turn on the axperimental tone mapping workflow. After switching this option on, restart the application. There will appear a link 'Tone Mapping' next to 'Image Stacking'.

    ^ Index :: ^ How to Use

    Recommendations on taking and processing theimages

    Some basic recommendations:

    RAW, unprocessed images

    Superresolution is intended to work with the images right as they come from the camera, with no processing applied.
    Use superresolution as the first step of your workflow.
    The best results are achieved with RAW images. Use RAW whenever is possible.

    Noise/blur tradeoff

    It is better to take sharper images with higher noise level, than blurry pictures with lower noise.
    Image fusion automatically reduces the noise by averaging it, while it's almost impossible to reduce a shaking blur without losing image detail.
    So, when taking the images handheld under low light conditions use a higher shutter speed and a higher ISO.

    For the consumer cameras there is yet another reason to use a high ISO when performing super-resolution.
    Most consumer cameras have built-in sharpening that is turned on at low ISO. This sharpening is very simple and imprecise. Unwanted artifacts (over-sharpening halos) and the loss of some details may appear in the final result.

    Product registration

    ^ Index :: ^ Product Registration

    Trial mode limitations

    In the trial mode PhotoAcute allows you to use all the image processing features.
    The trial mode is time-unlimited.
    The only limitation of the trial mode is that a watermark is placed in saved images. The watermark does not affect the image histogram, providing the possibility of examining the resulting images before purchasing the software.

    ^ Index :: ^ Product Registration

    How to register

    PhotoAcute license can be purchased online:

    Once the order is processed, you will be provided with a registration code. To register, launch PhotoAcute, click the Registration link, then the Enter registration code link. Enter the registrartion code and click Ok

    What's new in PhotoAcute version 3

    ^ Index :: ^ What's new in PhotoAcute version 3

    Features added in version 3

    64 bit OS support.

    PhotoAcute can utilize all the available memory, allowing to process larger images.

    Batch mode.

    Now you do not need to load each set of images, adjust the processing options and wait for processing to be finished to process the next set.
    Load all the images and process them in a batch.

    Faster UI.

    No need to wait for loading of the images, you can adjust the processing options and even start the processing while the images are being loaded.
    In the batch mode only the thumbnails of the images are loaded.
    RAW images are loaded faster as no conversion to DNG is performed.

    Adobe DNG Converter is not used for loading RAW images anymore.

    Loading RAW images is now less complicated and faster.

    Better handling of moving objects.

    When the moving objects cannot be removed they are de-ghosted to avoid any artefacts.

    Better handling of bayer patterns.

    The super resolution algorithm was improved to avoid grid artefacts with certain bayer patterns.

    Better locale support.

    No more problems with loading or saving the files with path/name containing non-latin1 characters.

    Licensing and Regitration.

    Single registration code for any license. One registration code for the versions for all OSs. No separate user name and registration code, the user data is embedded in the code.

    Experimental Tone Mapping workflow.

    PhotoAcute was always good at merging exposure bracketed photos into HDR images, but there was no exposure fusion and tone mapping features for creating viewable and printable LDR images.
    Version 3 introduces the tone mapping and the exposure fusion. This feature is in an experimental state now and is turned on in Settings/Advanced.

    ^ Index :: ^ What's new in PhotoAcute version 3

    Features to be added in the nearest future

    • Automatic updates.
    • Full tone mapping workflow.
    • Output of individual aligned images.
    • Manual fusion control: masks and shifts editor.

    ^ Index :: ^ What's new in PhotoAcute version 3

    Features absent in version 3

    A lot of features were introduced in PhotoAcute 3. At the same time some features available in version 2 are not available in version 3:
    • Command line switches. As the application now has a batch mode, there is no much sense in command line operation anymore.
    • Output of individual aligned images. This feature will be added in future.
    • Auto cropping of sample images for superresolution profiling. This will be added in future. Now the version 2 should be used for preparing the samples.
    • 'Wide shifts' alignment option. This option was excluded as it was practically unusable for normal photos, rather leading to confusingly wrong results sometimes.
    • 'Mask precision' option. The alignment algorithm was changed so that it should use only 'medium' setting.
    • 'Brightness equalization' option.
    • Loading frames from video files.
    Anyway, if you need some feature of version 2, you can install and use that version. Any registered user of PhotoAcute 3 will be provided with the registration codes for PhotoAcute 2 upon request.


    resolution, spatial resolution
    The resolution (commonly means spatial resolution) of a camera determines how small the image details it can capture are.
    The higher the resolution, the more details the image contains (smaller details are apparent), and the larger the size of the pictures that can be printed.
    Read more about image resolution at
    Read about effective resolution measurement at

    Super-resolution is the method of enhancing the resolution of an image or of an optical system.
    This can be done by either acquiring more graphic information (e.g. taking and merging several images of the same object) or by reconstructing the details lost due to the faultiness of the optical system (applying knowledge of the optical system's properties).
    PhotoAcute Studio uses both ways to achieve the maximum image quality. It also enhances the dynamic range and the tonal range as well as the spatial resolution.
    Read more about superresolution at Wikipedia

    noise, noise reduction
    Image noise is the additional signal generated by the electrical activity in the sensor.
    Noise is mostly visible on uniform surfaces (like blue skies) and in shadow areas.
    Noise increases with sensitivity (ISO), exposure and temperature.

    The main problem of noise reduction is that due to the impossibility of exact division of image data between useful signal and noise, noise reduction leads to the loss of image details. This becomes most apparent in low-lit areas of the image, where details are indistinguishable from noise and the noise reduction removes both the noise and those details.
    The noise reduction feature of PhotoAcute Studio is based on combining several photographs of the same scene, and it reduces the noise while leaving the image details.
    Read more about the image noise at
    Read more about the noise reduction at

    chromatic aberrations
    Every lens, to a greater or lesser extent, focuses the light of different wavelengths onto different focal planes and magnifies it differently. This causes, correspondingly, so-called "Longitudinal Chromatic Aberrations" and "Lateral Chromatic Aberrations". Chromatic aberrations are visible as the fringes of color at the contrast edges.
    Read more about chromatic aberrations at

    dynamic range
    The dynamic range (or luminosity range) of the scene is the ratio between the largest and the smallest values of luminosity in the scene. The dynamic range of a sensor is the ratio between the largest and the smallest signal it can generate. When the dynamic range of the camera is not enough to capture the dynamic range of the scene, shadow or/and highlight details are lost (clipped).

    The exposure determines the amount of light received by the sensor. It is the combination of the duration (shutter speed) and the width (aperture) of diaphragm opening.
    Read more about exposure at

    sensitivity, ISO
    ISO indicates the camera's sensitivity to light. The higher the sensitivity, the less light is needed to capture the scene. High ISO allows you to take photographs in low-light conditions and using faster shutter speed to avoid handshaking artifacts. However, since the higher sensitivity is achieved by amplifying the sensor's output, it leads to an increase of the noise.
    PhotoAcute Studio greatly suppresses the noise when processing a set of continuous photographs, thus eliminating the problem of high ISO and letting you use it for low-light scenes, thereby capturing and taking sharp photographs with fast shutter speed.
    Read more about sensitivity at

    continuous mode, burst mode, sequential mode
    Continuous mode (also called burst or sequential mode) is the camera mode whereby the images are taken immediately one after another.
    Different cameras provide different speeds for taking continuous photographs (frames per second or "fps") and maximum number of photographs in one sequence.
    Some cameras are capable of taking and saving continuous photographs only in JPEG format, while others are capable of taking continuous photographs in RAW.
    A number of modern mobile phones support continuous mode.
    Read more about continuous mode at

    exposure bracketing
    Exposure bracketing is a technique of taking several photographs of the same scene with different exposures.
    Bracketing is used when it is difficult to obtain a good image from a single shot, e.g. when the scene has both very dark and very light areas (the dynamic range of the scene is much wider than the dynamic range of the camera).
    Photographs taken in exposure bracketing mode can also be combined into one image with both dark and light areas normally exposed (the dynamic range of the image, thereby, becomes wider than the camera can capture).
    Read more about exposure bracketing at

    depth of field, focus stacking
    Depth of field (DOF) is the distance in front of and beyond the subject that appears to be in focus (sharp).
    Focus stacking is a digital image processing technique which combines multiple images taken at different focus distances to give a resulting image with a greater depth of field than any of the individual source images.
    Read more about depth of field at
    Read more about focus stacking at

    interpolation, nearest neighbor, bicubic
    Interpolation is the method used to scale the image to a different size.
    Nearest neighbor is the method of interpolation, which simply enlarges each pixel (when upscaling the image) or throws some pixels away (when downscaling the image). This method is very fast, but it produces rough, pixelized images.
    Bicubic interpolation computes each pixel color as a weighted average of the nearest 16 pixels. This method provides smoother edges but it is slower than the nearest neighbor method.

    profile, camera profile
    Two PhotoAcute Studio features - super-resolution processing and geometry correction are tuned for particular camera/lens models.
    To apply these features for processing certain photographs, the application needs information about the properties of the camera model which was used to take these photographs.
    This information is stored in the so-called camera profiles. The camera profile is a .dll/.bundle file, which is placed into PhotoAcute Studio installation folder and loaded automatically at the application startup.
    More information on cameras and lenses support can be found in PhotoAcute FAQ (on site)

    The image data in RAW format contain the image information as it comes from the sensor. Compared to the JPEG format, the RAW format provides more graphic data that can be used for applying sophisticated processing and thus producing high quality pictures.
    Read more about RAW at

    Visit product website:
    Contact PhotoAcute Studio support:
    © Almalence Inc. 2007-2011