Night Photo 2.0 is an application that allows you to take long exposure photos. It has these basic advantages:
- it is possible to see the nascent image (unlike any other camera - nothing is visible during the exposure) - so it is not needed to set the exposure time in advance
- 4 picture taking modes allowing to take long exposure photos at night but also during the day
- allows to control many camera parameters (resolution, ISO, EV, White balance, ...)
- has timer (to delay the shooting) and "start/stop" control over Bluetooth
- usage of the application requires higher maturity level: photography knowledges - long exposure photos are adding up the noise - the lower illumination the greater noise, a minimum level of illumination is required, knowledges about working with camera parameters to reduce noise, ...
- application runs with the OpenCV library: first test with OpenCV Manager if your device supports this library
- the best results are achieved by fixing the device on a tripod
How does Night Photo 2.0 work?
Every of the 4 modes is basically working on the principle of "addition" of images. The device measures the intensity of the light reaching each pixel of its sensor and displays the total amount of the light measured during the exposition (in the form of image on the screen) in every step of the measurement. According to the light conditions sometimes the measured light intensity is too high (the pixels are overburnt - white) or too low (the pixels are black) and to obtain the best possible result the application comes with 4 different shooting modes (depending on shooting during the day or at night):
Night Photo Mode
This mode should be used during photographing at night. The addition of the images is shown on the display without any changes. The whole amount of light measured with the sensor is shown.
Every sample image is added to the overall measurement with a weight the way that the total light intensity results in minimum overburnt pixels. The weights of the overall measurement and the actual sample are computed depending on the total number of samples processed.
This mode should be used during the day and it is possible to photograph moving objects leaving their paths on the image.
High Range Mode
This mode is similar to Weighted Mode, but the sum of the samples is computed with 64-bit precission (instead of 8-bit). The ascent image is recomputed in every step (to 8-bit) according to actual minimal and maximal values of the measurement accumulator. This produces overburnt pixels only if they reach the overall maximal value of the accumulator.
This mode is useable during the day as well as at night.
Parametric High Range Mode
This mode works as High Range Mode, but it is possible to change the parameters of the overall measurement. It is possible to change the Sensitivity by which the intensity value of every pixel is added to the 64-bit measurement accumulator.
It is also possible to select the minimal and maximal value (in percent) - a range - that is considered at the conversion to 8-bit image.
It means that for example if the measurement is taken during low light conditions, the setting of minimal and maximal values to <0, 10>% of the overall measurement, will produce an image with reinforced dark details. Please note that these images usually contains high level of noise, because the low intesity light often can not be measured with the sensor and the measurement is loaded with noise.
The other example is photographing during high light levels: setting the minimal and maximal values to <90, 100>%, will produce a final image where only the details with highest intesities will be shown in an normal 8-bit image intensity range.