Imgcomp: Configuring detection regions

When monitoring a scene using a Raspberry Pi and imgcomp, there are often regions of interest and other regions where motion is not of interest. Vegetation and flags waving in the wind can trigger motion without being an event of interest.

foo1.jpg - foo0.jpg: 0 at ( 0, 0) (time) fill 25-256,25-150 clear 128-256,25-75 Weight map: '-' = ignore, '1' = normal, '#' = 2x weight ---------------------------------------------------------------- ---------------------------------------------------------------- ---------------------------------------------------------------- ---------------------------------------------------------------- ---------------------------------------------------------------- ---------------------------------------------------------------- ---------------------------------------------------------------- -------1111111111111111111111111-------------------------------- -------1111111111111111111111111-------------------------------- -------1111111111111111111111111-------------------------------- -------1111111111111111111111111-------------------------------- -------1111111111111111111111111-------------------------------- -------1111111111111111111111111-------------------------------- -------1111111111111111111111111-------------------------------- -------1111111111111111111111111-------------------------------- -------1111111111111111111111111-------------------------------- -------1111111111111111111111111-------------------------------- -------1111111111111111111111111-------------------------------- -------1111111111111111111111111-------------------------------- -------111111111111111111111111111111111111111111111111111111111 -------111111111111111111111111111111111111111111111111111111111 -------111111111111111111111111111111111111111111111111111111111 -------111111111111111111111111111111111111111111111111111111111 -------111111111111111111111111111111111111111111111111111111111 -------111111111111111111111111111111111111111111111111111111111 -------111111111111111111111111111111111111111111111111111111111 -------111111111111111111111111111111111111111111111111111111111 -------111111111111111111111111111111111111111111111111111111111 -------111111111111111111111111111111111111111111111111111111111 -------111111111111111111111111111111111111111111111111111111111 -------111111111111111111111111111111111111111111111111111111111 -------111111111111111111111111111111111111111111111111111111111 -------111111111111111111111111111111111111111111111111111111111 -------111111111111111111111111111111111111111111111111111111111 -------111111111111111111111111111111111111111111111111111111111 -------111111111111111111111111111111111111111111111111111111111 -------111111111111111111111111111111111111111111111111111111111 -------111111111111111111111111111111111111111111111111111111111 ---------------------------------------------------------------- ---------------------------------------------------------------- ---------------------------------------------------------------- ---------------------------------------------------------------- ---------------------------------------------------------------- ---------------------------------------------------------------- ---------------------------------------------------------------- ---------------------------------------------------------------- ---------------------------------------------------------------- ----------------------------------------------------------------
By default, imgcomp will detect motion over the entire image.

The first way to configure what is of interest is to use the "region" and "exclude" options.

The "region" option specifies a rectangle within which detection is to be performed. Only one region can be specified. However, it's possible to specify areas to ignore within that region using the "exclude" option. For example, the following two options would produce an L shaped region of interest in 1024x768 images.

region = 100-1024,100-600 exclude = 512-1024,100-300

Imgcomp will output an ASCII representation of the happed regions. When operating on large images (as large as the camera will go), this map will cause line wraps in each line, so it will messed up unless you use a small font on a large monitor.

Imgcomp will not output this map until it reads the first image. Prior to the first image, imgcomp does not know what size the acquired images are.


Once the first image is read, if images of a different size are encountered, imgcomp will exit.

 

For more complex regions, specifying individual rectangles to itnore can be cumbersome. So another option imgcomp has is to read an image map indicating which parts of the image to ignore.

Weight map: '-' = ignore, '1' = normal, '#' = 2x weight -------------------------------------------------- -------------------------------------------------- -------------------------------------------------- -------------------------------------------------- -------------------------------------------------- -------------------------------111---------------- -------------------------------1111--------------- -------------------------------1111111111111111111 -------------------------------1111111111111111111 -------------------------------1111111111111111111 ----------111------------------11111111111111----- --------111111----------------111111111111111----- -1111111111111----------------11111111------------ 11111111111111----------------11111111------------ 11111111111111----------------11111111------------ 11111111111111----------------11111111------------ 111###11111111------------------------------------ 111###11111111------------------------------------ 111###11111111------------------------------------ 11111111111111------------------------------------ 11111111111111------------------------------------ 11111111111111------------------------------------ 1111111111111111---------------------------------- 1111111111111111---------------------------------- 1111111111111111---------------------------------- 1111111111111111---------------------------------- 1111111111111111---------------------------------- 1111111111111111111111111------------------------- 111111111111111111111111111----------------------- 11111111111111111111111111111--------------------- 1111111111111111111111111111111------------------- 11111111111111111111111111111111------------------ 1111111111111111111111111111111111---------------- 11111111111111111111111111111111111--------------- 11111111111111111111111111111111111111------------ 1111111111111111111111111111111111111111---------- 111111111111111111111111111111111111111111-------- 1111111111111111111111111111111111111111111-------
For the scene above, I want to ignore the tree (it moves with the wind) the roadway, and the adjoining driveway. So I take an image acquired by imgcomp and paint those regions to ignore with solid blue. Just for demonstration, I also coloured a region in solid red to indicate high interest in this region. Sensitivity in this region will be double. The red and blue need to be fullly saturated colours for imgcomp to use them. That way, the colours in most normal images will not accidentally trigger ignore or double mode.

On startup, imgcomp outputs the map at left.

When using image maps, the image map must be the same height and width as +all subsequent images.


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