Image transformation filters

Sharpness and Blur

Sharpness describes the clarity of detail in a photo, and can be a valuable creative tool for emphasizing texture. Proper photographic and post-processing technique can go a long way towards improving sharpness, although sharpness is ultimately limited by your camera equipment, image magnification and viewing distance.

The unsharp mask filter is commonly used for sharpening images. Three parameters are used for this task: radius, amount, and threshold. For downsized images, a typical improvement could be use an unsharp mask of 0.3 radius and 0.7-1.5 amount to make up the blurring introduced by the resize operation. With such a small radius value, one does not have to worry about halo artifacts.

Web images are commonly downsized to adjust their size to the visualization device. When downsizing we must minimize the possibility of aliasing and moirè. Sometimes, pre-blur can be used to minimize moiré artifacts. A little blur before downsize can improve results, but a too high can lead to softening in the final image.

The gaussian blur filter allows you to eliminate any detail smaller than what you know is impossible to capture at a lower resolution. If you do not have a problem with moiré artifacts, then there is no need to pre-blur. For instance, if an image is downsized by 1/4 its original size, any repeating pattern smaller than 4 pixels cannot be resolved. A radius of 2 pixels (for a total diameter of 4 pixels) can be used.

Image enhancement

building wall house architecture original

Original building wall house image

house color balanced

Parameters: f=cbalance

Description: Applies a simplest color balance..


house intensity balanced

Parameters: f=ibalance

Description: Applies a simplest intensity balance.


house tone mapped

Parameters: f=retinex

Description: Applies a retinex tone mapping.


house sharpen

Parameters: f=sharpen

Description: Applies a sharpen filter to the image.

Image effects

beach bungalow original

Original beach bungalow image

beach blur filter

Parameters: f=blur

Description: Applies a Gaussian blur filter to the image.


beach pixelate filter

Parameters: f=pixelate

Description: Applies a pixelizer filter to the image.


beach grayscale filter

Parameters: f=grayscale

Description: Converts the image to grayscale.


beach desaturate filter

Parameters: f=desaturate

Description: Desaturates the image.


beach brighten filter

Parameters: f=brighten

Description: Applies a brighten effect to the image.


beach contrast filter

Parameters: f=contrast

Description: Applies a contrast effect to the image.

beach sepia filter

Parameters: f=sepia

Description: Applies a sepia effect.


beach sunlight filter

Parameters: f=sunlight

Description: Applies a sunlight effect to the image.


beach lumo filter

Parameters: f=lumo

Description: Applies a lumo effect to the image.


beach country filter

Parameters: f=country

Description: Applies a country effect to the image.

beach cartoonify filter

Parameters: f=cartoonify

Description: Applies a cartoonify effect to the image.


beach sketch filter

Parameters: f=sketch

Description: Applies a sketch effect to the image.

beach crossprocess filter

Parameters: f=crossprocess

Description: Applies the crossprocess film effect filter.


beach velviaesque filter

Parameters: f=velviaesque

Description: Applies the velviaesque film effect filter.


beach proviaesque filter

Parameters: f=proviaesque

Description: Applies the proviaesque film effect filter.


beach portraesque filter

Parameters: f=portraesque

Description: Applies the portraesque film effect filter.

Chaining filters

Filters can be pipelined using the separator |. This can be useful to chain different effects. For example:

https://abraia.me/images?url=https://abraia.me/images/random.jpg&f=lumo|desaturate|darken
random example

Random example without any filter

random example with filters

Random example with a chain of filters

Actions

Actions are an experimental feature to provide a powerful content-based edition tool. They are going to be developed to enable smart actions like adaptive watermarking. For instance, changing the text color based on the background color, or using the negative space to place the watermark.

Anonymization

Taking advantage from Abraia face detection features you can easily anonymize any picture with just one command.

Anonymized couple picture

https://abraia.me/images/pexels-photo-289224.jpeg?w=500&atn=blur-faces

Meme

Action to easily create MEMES with just a simple url.

Meme action example

https://abraia.me/images/whale.jpeg?w=500&h=500&atn=meme&txt1=Hello!&fmt=jpg&txt2=Bye!

Caption

Action for a basic watermarking. Overlay the picture bottom with a semitransparent rectangle and centers the text inside it.

Caption action example

https://abraia.me/images/random.jpg?w=500&atn=caption&txt=Simple test