cvbase 0.5.5

Utils for computer vision research

# Introduction

[](https://pypi.python.org/pypi/cvbase)
[]()
[](https://travis-ci.org/hellock/cvbase)
[](https://codecov.io/gh/hellock/cvbase)


`cvbase` is a miscellaneous set of tools which maybe helpful for computer vision research.
It comprises the following parts.

- IO helpers
- Image/Video operations
- OpenCV wrappers for python2/3 and opencv 2/3
- Timer
- Progress visualization
- Plotting tools
- Object detection utils

Try and start with

```shell
pip install cvbase
```

See [documentation](http://cvbase.readthedocs.io/en/latest) for more features and usage.

## Some popular features
There are some popular features such as progress visualization, timer, video to frames/frames to videos.


- Progress visualization

If you want to apply a method to a list of items and track the progress, `track_progress`
is a good choice. It will display a progress bar to tell the progress and ETA.

```python
import cvbase as cvb

def func(item):
# do something
pass

tasks = [item_1, item_2, ..., item_n]

cvb.track_progress(func, tasks)
```

The output is like the following.

There is another method `track_parallel_progress`, which wraps multiprocessing and
progress visualization.

```python
import cvbase as cvb

def func(item):
# do something
pass

tasks = [item_1, item_2, ..., item_n]

cvb.track_parallel_progress(func, tasks, 8)
# 8 workers
```

- Timer

It is convinient to computer the runtime of a code block with `Timer`.

```python
import time

with cvb.Timer():
# simulate some code block
time.sleep(1)
```

Or try a more flexible way.

```python
timer = cvb.Timer()
# code block 1 here
print(timer.since_start())
# code block 2 here
print(timer.since_last_check())
print(timer.since_start())
```

- Video/Frames conversion

To split a video into frames.

```python
video = cvb.VideoReader('video_file.mp4')
video.cvt2frames('frame_dir')
```
Besides `cvt2frames`, `VideoReader` wraps many other useful methods to operate a video like a list object, like

```
video = cvb.VideoReader('video_file.mp4')
len(video) # get total frame number
video[5] # get the 6th frame
for img in video: # iterate over all frames
print(img.shape)
```

To generate a video from frames, use the `frames2video` method.

```python
video = cvb.frames2video('frame_dir', 'out_video_file.avi', fps=30)
```

- Video editing (needs ffmpeg)

To cut a video.

```python
cvb.cut_video('input.mp4', 'output.mp4', start=3, end=10)
```

To join two video clips.

```python
cvb.concat_video(['clip1.mp4', 'clip2.mp4'], 'output.mp4')
```

To resize a video.

```python
cvb.resize_video('input.mp4', 'resized.mp4', (360, 240))
# or
cvb.resize_video('input.mp4', 'resized.mp4', ratio=2)
```

To convert the format of a video.

```python
cvb.convert_video('input.avi', 'output.mp4', vcodec='h264')
```