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Questions tagged [exposure]

44 questions
8
votes
0 answers

How to accurately set fast shutter speeds (exposure duration) on an AVCaptureDevice?

I'm working on a camera app for IOS (13). For that I use an AVCaptureSession in conjunction with an AVCaptureVideoPreviewLayer. So far everything works fine. Now I want to let the user choose and set a custom shutter speed (exposure duration) out of…
marcoavol
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6
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1 answer

Can camera2 API tell me the difference between the current exposure and the ideal one?

We're building a camera app, and we want to use manual exposure. We don't want the exposure algorithm to set the ISO and exposure duration; instead we want it to tell us what the difference is between the manual exposure that we set and the correct…
Kartick Vaddadi
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6
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1 answer

Swift: autoFocus/Expose and continuousAutoFocus/Exposure at the same time?

Right now in my camera app I let the user touch anywhere to set the focus and exposure, but how can I get the best of both worlds just like Apple's Camera app? For instance, the user may want to touch to focus on something that is in the…
Chewie The Chorkie
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5
votes
1 answer

camera2 pixel values not linear to sensor exposure time

I tried to approximate raw sensor output with camera2 API using YUV_420_888 image format (raw not supported on my Sony XA1). I put everything to manual and deactivated every correction procedure I could find: …
hirnpilot
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3
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Can I get the Exif data from an Android camera preview without saving to file?

I want to use the Android camera to report lighting and colour information from a sampled patch on the image preview. The camerax preview generates ImageProxy images, and I can get the average LUV data for a patch. I would like to turn this data…
Richard Kirk
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3
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1 answer

How to change camera exposure on android?

I want to perform image processing with OpenCV and android. In the first step, I need to change the camera properties like resolution, exposure, etc. By using OpenCV I only can change the resolution(mOpenCvCameraView.setMaxFrameSize(320,240);) and…
Behzad
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Can be camera exposure change in web app?

Hi i want ask if there is way to change exposure( i only need change brighness) settings throw javascript. Using brightness throw pixels dont help, becouse i want use it to get wavelenght for spectrometer, that works corectly. Problem is when i…
Marek Skokánek
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2 answers

base_margin or init_score for catboost regressor

I would like to use a CatBoost regressor for insurance applications (Poisson objective). As I need to fix the exposure, how can I set the offset of log_exposure? When using xgboost I use "base_margin", while for lightgbm I use the "init_score"…
Giorgio Spedicato
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2
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2 answers

Android Camera2: How to implement an semi-automatic Shutter Speed Priority Mode

Goal Capture images with Android smartphones attached to moving vehicles frequency: 1 Hz reference model: Google Pixel 3a objects of interest: the road/way in front of the vehicle picture usage: as input for machine learning (like RNN) to identify…
hb0
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2
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2 answers

OpenCV Exposure Compensation Without The Need To Stitch Images

I have a bunch of images that have different exposures and I want to stitch them together: OpenCV has a Stitcher example but it relies on matching features between the images and they should overlap with each other. My images are not overlapping…
Cypher
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2
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1 answer

How to change the exposure of the photo in OpenCV

Is there a technique that allows you to change the exposure of a photo? I would like to know if there is a "generic" formula for having different degrees of exposure, for example: 1. Strongly underexposed 2. Underexposed 3. Correct exposure 4.…
Da Nio
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2
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Android Camera API exposureTargetOffset value

Would anyone know where I can find the exposureTargetOffset in Android Camera2 API? iOS developers has this property, but I cannot find it in Android. May be someone know how I can calculate it from current exposure value?
Sergey Yakimchik
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2
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Exposure variable in logistic regression

I have a data frame which contains some characteristics from clients and contracts and 0s and 1s showing whether a fall happened the period between 2008 and 2017. I'm using a binomial model to regress probability of fall on the characteristics. I…
user8558612
2
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0 answers

How to control exposure time with camera API in some Android phones

I use camera.getParameters() to get all camera parameters of the smart phone, and camera.getParameters.set(key, value) to control the target parameters. When I choose MX4 as my test phone, the parameters contain two parameters as follows:…
koma
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2
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1 answer

Android Camera2 - CONTROL_AE_REGIONS not working on Samsung devices

Using Android Camera2, I want to use a region to ignore the top 25% of the image when computing the exposure. I'm using this: // Compute the metering rectangle to ignore the top 25% of the picture: Rect newRect = new Rect(mActiveArraySize.left,…
Tim Autin
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