wiki:v2:video_api
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wiki:v2:video_api [2018/09/21 16:28] pixycam |
wiki:v2:video_api [2018/10/10 20:06] (current) jfrench added protocol reference link |
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| pixy.video.getRGB(50, 75, &r, &g, &b); // get red, green, blue values at location x=50, y=75 | pixy.video.getRGB(50, 75, &r, &g, &b); // get red, green, blue values at location x=50, y=75 | ||
| </code> | </code> | ||
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| + | See also the [[wiki:v2:general_api|Pixy2 General API]], [[wiki:v2:ccc_api|Color Connected Components API]], and [[wiki:v2:line_api|Line tracking API]] for other functionality. | ||
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| + | For a byte-level reference to the protocol, check out the new [[wiki:v2:protocol_reference|Pixy2 Serial Protocol - Packet Reference]] | ||
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| - | It is recommended to take a look at the _video\_get\_rgb example in the Arduino Pixy2 library._ | + | Take a look at the _video\_get\_rgb_ example in the Arduino Pixy2 library. |
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| + | Note, full frame-grabs are only supported through the USB interface and [[wiki:v2:building_the_libpixyusb_example_on_linux|libpixyusb]], not through the SPI, I2C or UART serial interfaces (i.e. Arduino). [[wiki:v2:building_the_libpixyusb_example_on_linux|Libpixyusb]] includes a frame-grab example called [[https://github.com/charmedlabs/pixy2/tree/master/src/host/libpixyusb2_examples/get_raw_frame|get_raw_frame]]. It uses a special function called getRawFrame() that isn't part of the video API. We could add this, but where would a 65K-byte raw frame fit in Arduino memory? :( | ||
| ==== Member functions ==== | ==== Member functions ==== | ||
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| - | The optional saturate argument when set to true (default) will scale all RGB values such that the greatest of three values is maximized (saturated) at 255. When set to false, the unmodified RGB values are returned. | + | The optional saturate argument when set to true (default) will scale all RGB values such that the greatest of the three values (r, g and b) is maximized (saturated) at 255. When set to false, the unmodified RGB values are returned. |
| - | getRGB() actually takes a 5x5 section of pixels centered at the x, y location and performs an average of all 25 pixels to obtain a representative result. | + | Instead of using just one pixel, getRGB() takes a 5x5 section of pixels centered at the x, y location and performs an average of all 25 pixels to obtain a representative result. Locations on the edge or close to the edge of the image are allowed, but will result in fewer pixels being averaged. |
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| - | . | + | Note, [[wiki:v2:pixymon_overview|PixyMon]] displays the x, y mouse location in image coordinates in the lower right corner of the main window to help determine the coordinates to request from getRGB(). |
wiki/v2/video_api.1537547295.txt.gz · Last modified: 2018/09/21 16:28 by pixycam
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