Discontinuation of 3D features in Photoshop
Photoshop’s 3D features will be removed in future updates. Users working with 3D are encouraged to explore Adobe’s new Substance 3D collection, which represents the next generation of 3D tools from Adobe. Additional details on the discontinuation of Photoshop’s 3D features can be found here: Photoshop 3D | Common questions on discontinued 3D features.
In Photoshop CS6, 3D functionality is part of Photoshop Extended. All features in Photoshop Extended are part of Photoshop. Photoshop does not have a separate Extended offering.
An image stack combines a group of images with a similar frame of reference, but differences of quality or content across the set. Once combined in a stack, you can process the multiple images to produce a composite view that eliminates unwanted content or noise.
You can use image stacks to enhance images in number of ways:
To reduce image noise and distortion in forensic, medical, or astrophotographic images.
To remove unwanted or accidental objects from a series of stationary photos or a series of video frames. For example, you want to remove a figure walking through an image, or remove a car passing in front of the main subject matter.
Image stacks are stored as Smart Objects. The processing options you can apply to the stack are called stack modes. Applying a stack mode to an image stack is a non-destructive edit. You can change stack modes to produce different effects; the original image information in the stack remains unchanged. To preserve changes after you apply the stack mode, save the result as a new image, or rasterize the Smart Object. You can create an image stack manually or using a script.
For best results, images contained in an image stack should have the same dimensions and mostly similar content, such as a set of still images taken from a fixed viewpoint, or a series of frames from a stationary video camera. The content of your images should be similar enough to allow you to register or align them to other images in the set.
An image stack must contain at least two layers.
You can also combine images using a script (File > Scripts > Load Files into Stack).
To make the Background layer selectable with the All Layers command, you must first convert it to a regular layer.
For noise reduction, use the Mean or Median plug‑ins.
For removing objects from the image, use the Median plug‑in.
The output is a composite image the same size as the original image stack. You may need to experiment with different plug‑ins to get the best enhancement for a particular image.
To change the rendering effect, choose a different Stack Mode from the submenu. Stack rendering is not cumulative—each render effect operates on the original image data in the stack and replaces previous effects.
Stack modes operate on a per-channel basis only, and only on non-transparent pixels. For example, the Maximum mode returns the maximum red, green, and blue channel values for a pixel cross section and merges them into one composite pixel value in the rendered image.
Rendering plug-in name |
Result |
Comments |
---|---|---|
Entropy |
entropy = - sum( (probability of value) * log2( probability of value) ) Probability of value = (number of occurrences of value) / (total number of non-transparent pixels) |
The binary entropy (or zero order entropy) defines a lower bound on how many bits would be necessary to losslessly encode the information in a set. |
Kurtosis |
kurtosis = ( sum( (value - mean)4 ) over non-transparent pixels ) / ( ( number of non-transparent pixels - 1 ) * (standard deviation)4 ). |
A measure of peakedness or flatness compared to a normal distribution. The kurtosis for a standard normal distribution is 3.0. Kurtosis greater than 3 indicates a peaked distribution, and kurtosis less than 3 indicates a flat distribution (compared to a normal distribution). |
Maximum |
The maximum channel values for all non-transparent pixels |
|
Mean |
The mean channel values for all non-transparent pixels |
Effective for noise reduction |
Median |
The median channel values for all non-transparent pixels |
Effective for noise reduction and removal of unwanted content from the image |
Minimum |
The minimum channel values for all non-transparent pixels |
|
Range |
Maximum minus the minimum of the non-transparent pixel values |
|
Skewness |
skewness = (sum( (value - mean)3 ) over non-transparent pixels ) / ( ( number of non-transparent pixels - 1 ) * (standard deviation)3 ) |
Skewness is a measure of symmetry or asymmetry around the statistical mean |
Standard Deviation |
standard deviation = Square Root(variance) |
|
Summation |
The sum channel values for all non-transparent pixels |
|
Variance |
variance = (sum( (value-mean)2 ) over non-transparent pixels ) / ( number of non-transparent pixels - 1) |
Because an image stack is a Smart Object, you can edit the original images that make up the stack layers at any time.
To preserve rendering effects on an image stack, convert the Smart Object to a regular layer. (You can copy the Smart Object before converting, in case you want to later re‑render the image stack.)
You can use the Statistics script to automate creating and rendering an image stack.
Files you select are listed in the dialog box.
Photoshop combines the multiple images into a single multilayered image, converts the layers into a Smart Object, and applies the selected stack mode.
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