Lines Matching +full:light +full:- +full:to +full:- +full:digital
1 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
3 .. _camera-controls:
10 digital) features of a device such as controllable lenses or sensors.
13 .. _camera-control-id:
23 .. _v4l2-exposure-auto-type:
28 enum v4l2_exposure_auto_type -
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41 * - ``V4L2_EXPOSURE_AUTO``
42 - Automatic exposure time, automatic iris aperture.
43 * - ``V4L2_EXPOSURE_MANUAL``
44 - Manual exposure time, manual iris.
45 * - ``V4L2_EXPOSURE_SHUTTER_PRIORITY``
46 - Manual exposure time, auto iris.
47 * - ``V4L2_EXPOSURE_APERTURE_PRIORITY``
48 - Auto exposure time, manual iris.
59 When ``V4L2_CID_EXPOSURE_AUTO`` is set to ``AUTO`` or
66 when ``V4L2_CID_EXPOSURE_AUTO`` control is set to ``AUTO``,
71 Increasing the exposure compensation value is equivalent to
73 light at the image sensor. The camera performs the exposure
76 .. _v4l2-exposure-metering:
81 enum v4l2_exposure_metering -
82 Determines how the camera measures the amount of light available for
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91 * - ``V4L2_EXPOSURE_METERING_AVERAGE``
92 - Use the light information coming from the entire frame and average
93 giving no weighting to any particular portion of the metered area.
94 * - ``V4L2_EXPOSURE_METERING_CENTER_WEIGHTED``
95 - Average the light information coming from the entire frame giving
96 priority to the center of the metered area.
97 * - ``V4L2_EXPOSURE_METERING_SPOT``
98 - Measure only very small area at the center of the frame.
99 * - ``V4L2_EXPOSURE_METERING_MATRIX``
100 - A multi-zone metering. The light intensity is measured in several
109 The unit is undefined. A positive value moves the camera to the
110 right (clockwise when viewed from above), a negative value to the
111 left. A value of zero does not cause motion. This is a write-only
118 a write-only control.
121 When this control is set, the camera moves horizontally to the
125 When this control is set, the camera moves vertically to the default
129 This control turns the camera horizontally to the specified
130 position. Positive values move the camera to the right (clockwise
131 when viewed from above), negative values to the left. Drivers should
132 interpret the values as arc seconds, with valid values between -180
136 This control turns the camera vertically to the specified position.
139 between -180 * 3600 and +180 * 3600 inclusive.
142 This control sets the focal point of the camera to the specified
144 closer to the camera, negative values towards infinity.
149 to the camera, negative values towards infinity. This is a
150 write-only control.
159 when ``V4L2_CID_FOCUS_AUTO`` is set to ``TRUE`` (1) is undefined,
165 disabled, that is when ``V4L2_CID_FOCUS_AUTO`` control is set to
168 .. _v4l2-auto-focus-status:
171 The automatic focus status. This is a read-only control.
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183 * - ``V4L2_AUTO_FOCUS_STATUS_IDLE``
184 - Automatic focus is not active.
185 * - ``V4L2_AUTO_FOCUS_STATUS_BUSY``
186 - Automatic focusing is in progress.
187 * - ``V4L2_AUTO_FOCUS_STATUS_REACHED``
188 - Focus has been reached.
189 * - ``V4L2_AUTO_FOCUS_STATUS_FAILED``
190 - Automatic focus has failed, the driver will not transition from
195 .. _v4l2-auto-focus-range:
200 enum v4l2_auto_focus_range -
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209 * - ``V4L2_AUTO_FOCUS_RANGE_AUTO``
210 - The camera automatically selects the focus range.
211 * - ``V4L2_AUTO_FOCUS_RANGE_NORMAL``
212 - Normal distance range, limited for best automatic focus
214 * - ``V4L2_AUTO_FOCUS_RANGE_MACRO``
215 - Macro (close-up) auto focus. The camera will use its minimum
217 * - ``V4L2_AUTO_FOCUS_RANGE_INFINITY``
218 - The lens is set to focus on an object at infinite distance.
224 zoom unit is driver-specific and its value should be a positive
228 Specify the objective lens focal length relatively to the current
230 telephoto direction, negative values towards the wide-angle
231 direction. The zoom unit is driver-specific. This is a write-only
236 reaches physical device limits or until an explicit request to stop
240 wide-angle direction. The zoom speed unit is driver-specific.
243 This control sets the camera's aperture to the specified value. The
251 write-only control.
255 is set to ``TRUE`` (1), no image can be captured by the camera.
256 Common means to enforce privacy are mechanical obturation of the
258 restricted to these methods. Devices that implement the privacy
262 Switch the band-stop filter of a camera sensor on or off, or specify
263 its strength. Such band-stop filters can be used, for example, to
264 filter out the fluorescent light component.
266 .. _v4l2-auto-n-preset-white-balance:
271 enum v4l2_auto_n_preset_white_balance -
272 Sets white balance to automatic, manual or a preset. The presets
273 determine color temperature of the light as a hint to the camera for
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284 * - ``V4L2_WHITE_BALANCE_MANUAL``
285 - Manual white balance.
286 * - ``V4L2_WHITE_BALANCE_AUTO``
287 - Automatic white balance adjustments.
288 * - ``V4L2_WHITE_BALANCE_INCANDESCENT``
289 - White balance setting for incandescent (tungsten) lighting. It
290 generally cools down the colors and corresponds approximately to
292 * - ``V4L2_WHITE_BALANCE_FLUORESCENT``
293 - White balance preset for fluorescent lighting. It corresponds
294 approximately to 4000...5000 K color temperature.
295 * - ``V4L2_WHITE_BALANCE_FLUORESCENT_H``
296 - With this setting the camera will compensate for fluorescent H
298 * - ``V4L2_WHITE_BALANCE_HORIZON``
299 - White balance setting for horizon daylight. It corresponds
300 approximately to 5000 K color temperature.
301 * - ``V4L2_WHITE_BALANCE_DAYLIGHT``
302 - White balance preset for daylight (with clear sky). It corresponds
303 approximately to 5000...6500 K color temperature.
304 * - ``V4L2_WHITE_BALANCE_FLASH``
305 - With this setting the camera will compensate for the flash light.
306 It slightly warms up the colors and corresponds roughly to
308 * - ``V4L2_WHITE_BALANCE_CLOUDY``
309 - White balance preset for moderately overcast sky. This option
310 corresponds approximately to 6500...8000 K color temperature
312 * - ``V4L2_WHITE_BALANCE_SHADE``
313 - White balance preset for shade or heavily overcast sky. It
314 corresponds approximately to 9000...10000 K color temperature.
318 .. _v4l2-wide-dynamic-range:
322 feature allows to obtain clear images in situations where intensity
328 .. _v4l2-image-stabilization:
335 sensitivity to light. The numbers are expressed in arithmetic scale,
342 ``V4L2_CID_ISO_SENSITIVITY_AUTO`` control is set to a value other
346 .. _v4l2-iso-sensitivity-auto-type:
351 enum v4l2_iso_sensitivity_type -
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360 * - ``V4L2_CID_ISO_SENSITIVITY_MANUAL``
361 - Manual ISO sensitivity.
362 * - ``V4L2_CID_ISO_SENSITIVITY_AUTO``
363 - Automatic ISO sensitivity adjustments.
367 .. _v4l2-scene-mode:
372 enum v4l2_scene_mode -
373 This control allows to select scene programs as the camera automatic
375 camera determines best exposure, aperture, focusing, light metering,
378 behavior in each mode is subject to the camera specification.
381 to ``V4L2_SCENE_MODE_NONE`` to make sure the other possibly related
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396 * - ``V4L2_SCENE_MODE_NONE``
397 - The scene mode feature is disabled.
398 * - ``V4L2_SCENE_MODE_BACKLIGHT``
399 - Backlight. Compensates for dark shadows when light is coming from
401 * - ``V4L2_SCENE_MODE_BEACH_SNOW``
402 - Beach and snow. This mode compensates for all-white or bright
403 scenes, which tend to look gray and low contrast, when camera's
404 automatic exposure is based on an average scene brightness. To
406 frames. The white balance may also be adjusted to compensate for
408 * - ``V4L2_SCENE_MODE_CANDLELIGHT``
409 - Candle light. The camera generally raises the ISO sensitivity and
411 close subject in the scene. The flash is disabled in order to
412 preserve the ambiance of the light.
413 * - ``V4L2_SCENE_MODE_DAWN_DUSK``
414 - Dawn and dusk. Preserves the colors seen in low natural light
418 * - ``V4L2_SCENE_MODE_FALL_COLORS``
419 - Fall colors. Increases saturation and adjusts white balance for
422 * - ``V4L2_SCENE_MODE_FIREWORKS``
423 - Fireworks. Long exposure times are used to capture the expanding
424 burst of light from a firework. The camera may invoke image
426 * - ``V4L2_SCENE_MODE_LANDSCAPE``
427 - Landscape. The camera may choose a small aperture to provide deep
428 depth of field and long exposure duration to help capture detail
429 in dim light conditions. The focus is fixed at infinity. Suitable
431 * - ``V4L2_SCENE_MODE_NIGHT``
432 - Night, also known as Night Landscape. Designed for low light
434 out bright objects. The camera generally sets itself to a
435 medium-to-high ISO sensitivity, with a relatively long exposure
438 * - ``V4L2_SCENE_MODE_PARTY_INDOOR``
439 - Party and indoor. Designed to capture indoor scenes that are lit
442 low light conditions.
443 * - ``V4L2_SCENE_MODE_PORTRAIT``
444 - Portrait. The camera adjusts the aperture so that the depth of
445 field is reduced, which helps to isolate the subject against a
447 the scene and focus on them. The color hue is adjusted to enhance
449 * - ``V4L2_SCENE_MODE_SPORTS``
450 - Sports. Significantly increases ISO and uses a fast shutter speed
451 to freeze motion of rapidly-moving subjects. Increased image noise
453 * - ``V4L2_SCENE_MODE_SUNSET``
454 - Sunset. Preserves deep hues seen in sunsets and sunrises. It bumps
456 * - ``V4L2_SCENE_MODE_TEXT``
457 - Text. It applies extra contrast and sharpness, it is typically a
458 black-and-white mode optimized for readability. Automatic focus
459 may be switched to close-up mode and this setting may also involve
460 some lens-distortion correction.
470 by setting the corresponding lock bit to 1. The camera then retains
475 requests to lock it and should return no error. An example might be
477 ``V4L2_CID_AUTO_WHITE_BALANCE`` control is set to ``FALSE``. The
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487 * - ``V4L2_LOCK_EXPOSURE``
488 - Automatic exposure adjustments lock.
489 * - ``V4L2_LOCK_WHITE_BALANCE``
490 - Automatic white balance adjustments lock.
491 * - ``V4L2_LOCK_FOCUS``
492 - Automatic focus lock.
498 The unit is undefined. A positive value moves the camera to the
499 right (clockwise when viewed from above), a negative value to the
509 .. _v4l2-camera-sensor-orientation:
512 This read-only control describes the camera orientation by reporting its
517 as a position relative to the device's intended usage orientation. For
518 example, a camera installed on the user-facing side of a phone, a tablet or
519 a laptop device is said to be have ``V4L2_CAMERA_ORIENTATION_FRONT``
521 is said to be have ``V4L2_CAMERA_ORIENTATION_BACK`` orientation. Camera
522 sensors not directly attached to the device, or attached in a way that
523 allows them to move freely, such as webcams and digital cameras, are said to
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533 * - ``V4L2_CAMERA_ORIENTATION_FRONT``
534 - The camera is oriented towards the user facing side of the device.
535 * - ``V4L2_CAMERA_ORIENTATION_BACK``
536 - The camera is oriented towards the back facing side of the device.
537 * - ``V4L2_CAMERA_ORIENTATION_EXTERNAL``
538 - The camera is not directly attached to the device and is freely movable.
541 .. _v4l2-camera-sensor-rotation:
544 This read-only control describes the rotation correction in degrees in the
545 counter-clockwise direction to be applied to the captured images once
546 captured to memory to compensate for the camera sensor mounting rotation.
548 For a precise definition of the sensor mounting rotation refer to the
550 bindings file 'video-interfaces.txt'.
552 A few examples are below reported, using a shark swimming from left to
553 right in front of the user as the example scene to capture. ::
555 0 X-axis
556 0 +------------------------------------->
567 Y-axis
569 Example one - Webcam
574 images are meant to be displayed in landscape mode (width > height) on the
577 The camera is typically mounted upside-down to compensate the lens optical
579 V4L2_CID_CAMERA_SENSOR_ROTATION control is 0, no rotation is required to
580 display images correctly to the user.
582 If the camera sensor is not mounted upside-down it is required to compensate
585 result rotated when captured to memory. ::
587 +--------------------------------------+
597 +--------------------------------------+
599 A software rotation correction of 180 degrees has to be applied to correctly
602 +--------------------------------------+
612 +--------------------------------------+
614 Example two - Phone camera
616 It is more handy to go and swim with sharks with only your mobile phone
619 to be displayed in portrait mode (height > width) to match the device screen
623 aligned to the device longer side, upside-down mounted to compensate for
626 The images once captured to memory will be rotated and the value of the
630 +-------------------------------------+
640 +-------------------------------------+
642 A correction of 90 degrees in counter-clockwise direction has to be
643 applied to correctly display the image in portrait mode on the device
646 +--------------------+
661 +--------------------+
665 This control may be changed to a menu control in the future, if more
674 control and are left to the programmer.